Podcasts about long qt

Dr. Amit Goyal, along with episode chair Dr. Dinu Balanescu (Mayo Clinic, Rochester), and FIT leads Dr. Sonu Abraham (University of Kentucky) and Dr. Natasha Vedage (MGH), dive into the fascinating topic of channelopathies with Dr. Michael Ackerman, a genetic cardiologist and professor of medicine, pediatrics, and pharmacology at Mayo Clinic, Rochester, Minnesota. Using a case-based approach, they review the nuances of diagnosis and treatment of channelopathies, including Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia (CPVT), and long QT syndrome. Dr. Sonu Abraham drafted show notes. Audio engineering for this episode was expertly handled by CardioNerds intern, Christiana Dangas. The CardioNerds Beyond the Boards Series was inspired by the Mayo Clinic Cardiovascular Board Review Course and designed in collaboration with the course directors Dr. Amy Pollak, Dr. Jeffrey Geske, and Dr. Michael Cullen. CardioNerds Beyond the Boards SeriesCardioNerds Episode PageCardioNerds AcademyCardionerds Healy Honor Roll CardioNerds Journal ClubSubscribe to The Heartbeat Newsletter!Check out CardioNerds SWAG!Become a CardioNerds Patron! Pearls and Quotes - Channelopathies One cannot equate the presence of type 1 Brugada ECG pattern to the diagnosis of Brugada syndrome. Clinical history, family history, and/or genetic testing results are required to make a definitive diagnosis. The loss-of-function variants in the SCN5A gene, which encodes for the α-subunit of the NaV1.5 sodium channel, is the only Brugada susceptibility gene with sufficient evidence supporting pathogenicity. Exertional syncope is an “alarm” symptom that demands a comprehensive evaluation with 4 diagnostic tests: ECG, echocardiography, exercise treadmill test, and Holter monitor. Think of catecholaminergic polymorphic ventricular tachycardia (CPVT) in a patient with exertional syncope and normal EKG! ICD therapy is never prescribed as monotherapy in patients with CPVT. Medical therapy with a combination of nadolol plus flecainide is the current standard of care. Long QT syndrome is one of the few clinical scenarios where genetic testing clearly guides management, particularly with respect to variability in beta-blocker responsiveness. Notes - Channelopathies 1. What are the diagnostic criteria for Brugada syndrome (BrS)? Three repolarization patterns are associated with Brugada syndrome in the right precordial leads (V1-V2): Type 1: Prominent coved ST-segment elevation displaying J-point amplitude or ST-segment elevation ≥2 mm, followed by a negative T wave. Type 2/3: Saddleback ST-segment configuration with variable levels of ST-segment elevation. It is important to note that only a type 1 pattern is diagnostic for Brugada syndrome, whereas patients with type 2/3 patterns may benefit from further testing. The Shanghai score acknowledges that relying solely on induced type 1 ECG changes has limitations. Therefore, one cannot equate the presence of a type 1 Brugada ECG pattern alone to the diagnosis of Brugada syndrome. The score suggests incorporating additional information—such as clinical history, family history, and/or genetic testing results—to achieve a definitive diagnosis. 2. What is the significance of genetic testing in Brugada syndrome? There are 23 alleged Brugada syndrome susceptibility genes published with varying levels of evidence. However, only one gene mutation, the loss-of-function variants in the SCN5A gene encoding for the α-subunit of the NaV1.5 sodium channel, is considered to have sufficient evidence. The overall yield of BrS genetic testing is 20%. The presence of PR prolongation (>200 ms) along with type I EKG pattern increases the yield to 40%. On the contrary, in the presence of a normal PR interval, the likelihood of SCN5A positivity drops to

We sit down with Andy as she shares the emotional journey of losing her son, Xavier. Andy's Writing (The Gift to be Healed) Like A River - Book Amazon Affiliate Link Support The Pod on Patreon In October 2023, Xavier suffered a cardiac arrest caused by Long QT syndrome, an electrical issue with the heart. Despite efforts to revive him, Xavier's condition was dire. Andy recounts the heartbreaking experience of seeing her son in a coma and the difficult decision to remove him from life support after he failed to progress through the phases of consciousness. Xavier's story is a poignant reminder of the fragility of life and the strength of a mother's love. Join us as we explore Andy's story, from the initial shock to the profound grief, and the steps she's taking towards healing.

Welcome to my podcast. I am Doctor Warrick Bishop, and I want to help you to live as well as possible for as long as possible. I'm a practising cardiologist, best-selling author, keynote speaker, and the creator of The Healthy Heart Network. I have over 20 years as a specialist cardiologist and a private practice of over 10,000 patients. Doctor Warrick Bishop discusses various topics from a cardiology conference, including long QT syndrome and how stress testing can help evaluate it. He highlights that only 32% of patients with high blood pressure have it adequately controlled. Doctor Bishop also notes the complexities of managing pregnant patients with mechanical heart valves, as anticoagulation treatment needs careful monitoring. The podcast provides insights from medical experts on important cardiovascular issues like blood pressure management and risks during pregnancy, helping listeners understand heart health.

Pyotr Platonov, MD, PhD, FESC, FHRS, tar hand om patienter med hjärtsjukdomar och klar genetisk koppling. Han presenterar en studie som visar på att det är mot förmodan ett relativt stort antal patienter som är mutationsbärare som har normala QT-tide. PP-ELI-SWE-2803

How do you cope when your body fails? Today we talk to my nephew who despite a broken heartbeat is thriving, his motto never give up We tend to think of heart attacks happening to 40-50 year adults yet today we talk to my nephew, the super resilient Chris Allenby who survived multiple heart failures before he completed primary school. I can still remember our shock when we heard he had Long QT, also known as SADS-Sudden Adult Death Syndrome. Now in his 30s, very little was known about his heart condition and there were even fewer survivors. We talk about how it has changed both his life and that of the family. Follow: @allenbychristopher on instagram #heartattack #sads #heartfailure #anxiety #depression #longQT #realtalk #mentalhealth #unexpectedturnspod #unexpectedturns #trains

The fetal heart rate is controlled by various integrated physiological mechanisms, most importantly by a balance of parasympathetic and sympathetic nerve impulses. Intrapartum, fetal bradycardia may be in direct response to an evolving or acute hypoxic event, including tachysystole, uterine rupture, or placental abruption. Antepartum, excluding acute events like maternal trauma which could lead to an acute hypoxic episode, most fetal brady arrhythmias will be nonhypoxia related. We recently evaluated and cared for a patient at 23 weeks gestation with the incidental finding during her routine prenatal visit of a fetal HR of 90. This was confirmed by bedside ultrasound, and then noted to be in the 70s on reexamination in L&D. There was no fetal hydrops, no evidence of maternal injury, no maternal connective tissue disease, normal amniotic fluid, and a normal fetal movement seen on ultrasound. What are the possible causes of antepartum fetal bradyarrhythmia? What's the work-up? What is the fetal Long QT syndrome? And when is delivery recommended? Listen in and find out.

Delaney Middlebrook is the fourth guest in the “Minnesota Chronicles”, a special series from my time in Minnesota for the Boys State High School Tourney. Delaney shared an incredible story, filled with so much challenge, so many tales of overcoming those difficulties, and she shares how she has become the wonderful human I was able to meet for a bit. From asking to play hockey at 4, and making a promise to never quit to her father (Chris Middlebrook), to learning about her Long QT syndrome, to playing six years of high school hockey. She was not done there. Delaney played four years of D1 hockey at two different schools, and then followed that up with some pro experience in Europe. Enjoy! https://www.beautyunis.com/ https://www.thegardensicehouse.com/ https://otpsteamboat.com/ https://4starautorepair.com/ https://www.yampavalleybank.com/

Name/Class: Pepcid) Anti-Ucler Agent / H2-Receptor AntagonistDescription: Famotidine is a histamine-2 blocker. It works by decreasing the amount of acid the stomach produces.Indications: Upper GI Bleed, Anaphylaxis.Contraindications: Hypersensitivity, Long QT syndrome.Precautions: Asthma, COPD.Dosage/Route: 20mg IV

Dr. Annika Winbo phones up to talk about her research into Long QT syndrome. Whakarongo mai! 

Dr. Henry Colecraft is the John C. Dalton Professor of Physiology and Cellular Biophysics at Columbia and the inventor of engineered deubiquitinases, a breakthrough innovation that rescues proteins marked for destruction by many genetic diseases including cystic fibrosis, Long QT syndrome, and potentially many others. He shares what it's like to launch his new startup with a huge Series A investment from prominent venture capitalists; the critical role that graduate students and postdocs play in university innovation; and how Sherlock Holmes inspired him to become a scientist.

Katherine Standefer discusses her book Lightning flower and living with the genetic heart condition that lead to the books conception.

CardioNerd (Amit Goyal), cardioobstetrics series co-chair Dr. Natalie Stokes, Cardionerds Duke University CardioNerds Ambassador and episode lead fellow, Dr. Kelly Arps, join Dr. Andrea Russo, Director of Electrophysiology and Arrhythmia Services at Cooper Medical School of Rowan University and immediate past president Heart Rhythm Society, for a discussion about pregnancy and arrhythmia. Stay tuned for a message from Dr. Sharonne Hayes about WomenHeart. Audio editing by Gurleen Kaur. Claim free CME for enjoying this episode! Dr. Russo's disclosures: Johnson and Johnson, Medtronic, Inc., Boston Scientific Corporation, Kestra, Medilynx, Up-to-Date, and ABIM. Abstract • Pearls Notes • References • Guest Profiles • Production Team CardioNerds Cardio-Obstetrics Series PageCardioNerds Episode PageCardioNerds AcademyCardionerds Healy Honor Roll CardioNerds Journal ClubSubscribe to The Heartbeat Newsletter!Check out CardioNerds SWAG!Become a CardioNerds Patron! Episode Abstract Pregnant patients may have exacerbation of underlying arrhythmic syndromes or unmasking of previously undiagnosed arrhythmic syndromes. Management of atrial and ventricular tachyarrhythmias should proceed with increased urgency in pregnant patients due to risk of adverse hemodynamic events in the mother and fetus. Cardioversion of atrial and ventricular arrhythmias is safe in pregnancy. Preferred antiarrhythmic agents in pregnant patients include metoprolol, propranolol, verapamil, flecainide, propafenone, sotalol, procainamide, and lidocaine. Management of arrhythmias in pregnancy should include collaboration with obstetrics and maternal-fetal medicine teams. Pearls Pre-conception counseling is a shared decision making process; include obstetrics and maternal-fetal medicine colleagues in challenging cases. Have a high sense of urgency for acute arrhythmias in pregnancy due to risk of impaired fetal perfusion. Goals of acute arrhythmic management should include rapid treatment while avoiding hypotension. In scenarios when beta blockers are indicated, metoprolol and propranolol are first choice. Avoid atenolol as this drug has the highest risk of fetal bradycardia and intra-uterine growth retardation in the class. Lidocaine or procainamide should be first line for ventricular arrhythmias in pregnancy. Amiodarone is potentially teratogenic and should not be used in pregnant patients unless all other options have been exhausted. Show notes 1. What are the expected electrophysiologic changes associated with pregnancy? Increase in resting heart rate which peaks in third trimesterPR shorteningECG axis shift leftward and upwardNon-specific ST and T wave changes These changes, along with increased cardiac output and volume with increased stretch in all chambers, increase the risk of re-entrant arrhythmias in those who are predisposed. ↑ atrial volume -> ↑ stretch -> ↑ ectopy -> ↑ risk for re-entrant arrhythmias 2. What is the approach to pre-conception counseling for patients with known arrhythmias or arrhythmic syndromes? Anticipate frequency and potential severity of adverse arrhythmic outcomes during pregnancy and post-partum periodConsider available options for rhythm control and anticoagulation therapy, as appropriate, during the pre-conception, pregnancy, and post-partum periodsConsider catheter ablation prior to pregnancy, particularly for curable arrhythmias such as Wolff-Parkinson-White (WPW) and AVNRT   Offer genetic counseling about hereditary risk to fetus for inherited arrhythmias such as Brugada syndrome and Long QT syndrome 3. What is the management of SVT in pregnancy? Consider the increased risk of tachyarrhythmias in pregnancy: Typically benign arrhythmias can lead to more rapid decompensation in mother due to increased baseline cardiac output. Typically benign arrhythmias can lead to rapid danger to the fetus due to maternal hypotension and shortened diastolic ...

For this week's Feature Discussion, please join authors Igor Klem, Pasquale Santangeli, Mark N.A. Estes III, and Associate Editor Victoria Delgado as they discuss, in a panel forum, the articles: " The Relationship of LVEF and Myocardial Scar to Long-Term Mortality Risk and Mode of Death in Patients with Non-Ischemic Cardiomyopathy," "Prognostic Value of Non-Ischemic Ring-Like Left Ventricular Scar in Patients with Apparently Idiopathic Non-Sustained Ventricular Arrhythmias," and "Cardiac Magnetic Resonance Imaging in Nonischemic Cardiomyopathy: Prediction Without Prevention of Sudden Death." Dr. Carolyn Lam: Welcome to Circulation on the run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-hosts. I'm Dr. Carolyn Lam, Associate editor from the National Heart Center and Duke National University of Singapore. Dr. Greg Hundley: And I'm Dr. Greg Hundley, Associate editor, Director of the Pauley Heart Center in Richmond, Virginia. Well Carolyn, this week we've got another sort of double feature with a forum and our focus is going to be on myocardial scar that's observed with late gadolinium enhancement during cardiovascular magnetic resonance and the two author groups we'll be discussing the impact of that scar on the development of ventricular arrhythmias. But before we get to that, how about we grab a cup of coffee and jump into the other articles in the issue? Would you like to go first? Dr. Carolyn Lam: I certainly would. Although I have to say, can't wait for the double feature. I love those, and this is right up your alley too. All right. But first, the first paper I want to talk about provides new randomized trial information regarding the benefits of catheter ablation in atrial fibrillation in patients who also have heart failure. Now, this is a sub-study of the CABANA trial. Dr. Greg Hundley: So Carolyn, remind us a little bit about the CABANA trial first. Dr. Carolyn Lam: I thought you might ask. Well, CABANA randomized 2,204 patients with atrial fibrillation who were 65 years or older or less than 65 with one or more risk factors for stroke at, it was huge at 126 sites, and they were randomized to ablation with pulmonary vein isolation or drug therapy. Now of these, 35% of 778 patients had New York Heart Association Class II or higher at baseline, and really formed the subject of the current paper. Although this sub-study was not specifically designed to evaluate patients with heart failure with preserved ejection fraction, about 91% of the patients with a clinical diagnosis of heart failure participating in CABANA for whom such data on injection fraction were available, really had an ejection fraction of above 40% and fully 79% had an ejection fraction above 50%. So excitingly, this is really majority talking about, have HFpEF. Now, what did they find well in patients with New York heart Association Class II or III heart failure at trial entry, most of whom did not have a reduced ejection fraction. Dr. Carolyn Lam: There was substantial clinical outcome benefits with the ablation over drug therapy with a 36% relative reduction in the primary composite endpoint of death, disabling stroke, serious bleeding or cardiac arrest. Benefits were evident for both all-cause mortality and atrial fibrillation reduction. However, the effects on heart failure hospitalization were small and not significant. Authors also caution that these results should not be viewed as practice changing until they are reproduced in a confirmatory trial of ablation in the same population. And this is beautifully discussed in an editorial by Lynda Rosenfeld and Alan Enriquez from Yale University School of Medicine. Dr. Greg Hundley: Oh, wow. Thanks Carolyn. Well, my first paper comes from the world of basic science and it's from Professor Thomas Braun, from the Max Planck Institute for Heart and Lung Research. So Carolyn, vascular smooth muscle cells show a remarkable phenotypic plasticity allowing acquisition of contractile or synthetic states, but critical information is missing about the physiological signals that promote formation and maintenance of contractile vascular smooth muscle cells in vivo. So BMP-9 and BMP-10 are known to regulate endothelial quiescence after secretion from the liver and right atrium. And these investigators are studied the role of BMP-9 and 10 for controlling formation of contract, all vascular smooth muscle cells. Dr. Carolyn Lam: Greg, talking about vascular smooth muscle cells always reminds me of their role in pulmonary hypertension, am I right? Dr. Greg Hundley: Yes, Carolyn. So these investigators found that in mouse models, BMP-9 and BMP-10 act directly on vascular smooth muscle cells for induction and maintenance of their contractile state, and surprisingly the effects of BMP-9 and 10 in vascular smooth muscle cells are mediated by different combinations of BMP type 1 receptors in a vessel bed specific manner. And therefore, just as you suggest, Carolyn, these results may offer new opportunities to manipulate blood pressure in the pulmonary circulation. Dr. Carolyn Lam: Thank you, Greg. Well, my next paper provides the first proof of principle of gene therapy for complete correction of Type 1 Long QT syndrome. Dr. Greg Hundley: Ah, so tell us a little bit about Type 1 Long QT syndrome, Carolyn. Dr. Carolyn Lam: Okay. Well Type 1 long QT syndrome is caused by loss of function variants in the KCNQ1 and coded potassium channel alpha sub-unit. And that is essential for cardiac repolarization providing the slow delayed rectifier current. Now no current therapies target the molecular cause of this Type 1 long QT syndrome. Well, this study from Dr. Michael Ackerman colleagues from Mayo Clinic Rochester really established a novel dual component suppression and replacement KCNQ1 gene therapy approach for Type 1 long QT syndrome. And it's the type that contains the KCNQ1 short hairpin RNA to suppress endogenous expression and a codeine altered short hairpin RNA immune copy of this KCNQ1 for gene replacement. Dr. Carolyn Lam: So this very novel approach rescued the prolonged action potential duration in inducible pluripotent STEM cell cardiomyocytes derived from four patients with unique Type 1 Long QT syndrome, causative, KCNQ1 variants. So it's super cool. Just go have a look. Dr. Greg Hundley: Well, thanks Carolyn. Dr. Carolyn Lam: I want to also tell you about other things in the mail bag. We have ECG Challenge by Dr. Dai on “Severe Arrhythmia Caused by a Chinese Herbal Liqueur. What's the Diagnosis?” I'm not going to tell you. You have to go see. We have Dr. Karen Sliwa writing a beautiful Joint Opinion paper from the World Heart Federation and American College of Cardiology, American Heart Association, and European Society of Cardiology on "Taking a Stand Against Air Pollution, the Impact on Cardiovascular Disease." Dr. Greg Hundley: Well, thanks Carolyn. So I've got a couple other articles. First Professor Yacoub has a global rounds describing and working towards meeting the challenges of improving cardiovascular health in Egypt. Those are really interesting features to learn about cardiovascular care worldwide. Next there's an In Depth article by Professor Thum entitled, "Therapeutic and Diagnostic Translation of Extracellular Vesicles in Cardiovascular Diseases, Roadmap to the Clinic." And then finally, a Research Letter from Dr. Bottá entitled, "Risk of Coronary Artery Disease Conferred by Low Density Lipoprotein Cholesterol Depends on Apologetic Background." Well, Carolyn, what a great issue and how about now we proceed on to that double feature? Dr. Carolyn Lam: Oh, I can't wait. Thanks Greg. Dr. Greg Hundley: Well, listeners, we are here for a really exciting feature discussion today that's going to focus on imaging, in particular magnetic, resonance imaging, and some new findings in that era and how those findings may pertain to ventricular dysrhythmias. With us today, we have Dr. Igor Klem from Duke University who will be discussing a paper, Dr. Pasquale Santangeli from University of Pennsylvania, our own associate editor, Dr. Victoria Delgado from Leiden and an editorialist, Dr. Mark Estes from UPMC in Pittsburgh. Welcome to all of you. Well, Igor, we're going to start with you. Could you tell us what was the hypothesis for your study and what was your study population in study design? Dr. Igor Klem: Yes. Good morning, Greg and thanks for the invitation. We wanted to know if you have a patient who you diagnosed with non ischemic cardiomyopathy based on clinical grounds and you refer him for a cardiac MRI study with contrast, what is the additional information that you get from the MRI study? And so we wanted to compare, and that's primarily related to the findings on scar imaging with late gadolinium enhancement. And we wanted to compare that to one of the most robust clinical parameters in cardiology, which is left ventricular ejection fraction, and in particular using a cutoff of 35%, which somehow in our clinical management has sort of as established as a break point for many clinical decisions. Dr. Igor Klem: And so we created a registry among three centers of patients who undergo a cardiac MRI study, where we found an LVEF of less than 50% and we followed them for a number of outcomes. One is all caused death. And then we wanted to separate a little bit the events into those who have cardiac mortality to look at a little epidemiology because in those patients, we have two major adverse events: one as heart failure related mortality. One is arrhythmia related mortality. Dr. Greg Hundley: And how many subjects did you include? Dr. Igor Klem: We included about a thousand patients from three centers and coming to the major findings of our study, we found that both left ventricular ejection fraction, as we know, is a robust marker of all cause mortality and cardiac death. And so it was the presence of myocardial scar on cardiac MRI. But the major difference was in relation to the arrhythmic events. We founded left ventricular ejection fraction in particular, when we use the 35% cutoff actually had very little predictive power to inform us who is at risk of arrhythmic events. In contrast, there was a very strong and robust relationship or multiple statistical methods to stratify patients who are at risk for sudden cardiac death, appropriate ICD shock, as well as arrhythmic cardiac death. Dr. Greg Hundley: Very good. Well, Pasquale understand you also performed a research study utilizing cardiovascular magnetic resonance. Could you describe for us your hypothesis as well as what was your population and your study design? Dr. Pasquale Santangeli: Thank you, Greg. And of course, thanks to the editor for the interest in our paper. I need to thank also the first call authors Daniele Muser and Gaetano Nucifora for putting together a registry of 70 institutions throughout the U.S., Europe, and Japan and the our hypothesis came from a clinical need. We do know that patients with idiopathic ventricular re we ask, which includes not sustain a weakness like PVCs or non-sustained VT. Very few of them, but there is a group of them that have a higher risk of ending malignant and up comes in terms of your ethnic events over follow-up. And prior studies have shown that by doing an MRI and showings and the detecting scar related announcement, there is an increase with how we make events of a follow-up. However, if you do look at those studies late, an answer's been reported in up to 70% of these patients, which you never view is a highly practical way of re-stratifying these patients, because you have a risk factor that is present 70% of those, then it's hard to use it for clinical decision-making. Dr. Pasquale Santangeli: So in this registry, which you put it again at 686 patients with panel data idiopathic, not sustained ventricular arrhythmias, which were defined by a normal WBC gene status, a normal echocardiogram and a normal stress test. We looked at whether there is a specific pattern of late announcement. So how basically I believe lands, and it looks on the MRI, they may predict better or outcomes over follow-up. And again, we use a composite and Pauline the full cost mortality, but associated cardiac arrest due to ventricular fibrillation or a hemodynamically unstable BP, or in a subgroup of patients that underwent ICD therapy. We also looked at, I approve SED shocks. Dr. Pasquale Santangeli: The groups were divided in three different categories. The first one, which is a larger group of 85% of patients and no late announcement. The second group, the one with late announcement, which represents the remaining 50% of 15% of patients, we divided it into a ring light pattern, which was defined as that word says, as a ring like distribution of the lead announcement in the mid-market segments, which involves a three consecutive continuous segments in a short axis view. It looks like really at least half the ring or three-quarters of the ring. Dr. Pasquale Santangeli: And the other group is the one that had the leader announcement without a ring light pattern. And it's interesting that the third and the latest announcement was not that similar between the ring light and the one without ring light late announcement. What we did find though for our follow-up the patient with a ring light pattern, a significantly higher rate of the primary composite endpoint, which happened in the median follow-up about 61 months so it was quite long. And the composite outcome occurred in 50% of patients in the ring light group versus 19% in the no ring light a positive announcement group and a 0.3%. So really, really rare in patients. So then concluded that of course, late announcement does provide some information in general, particularly the type of announcement that increases the risk significantly. Probably although this has to be confirmed prospective fashion patient with a ring light pattern may benefit from other forms of interventions, including potentially defibrillator therapy in a prophylactic fashion. Dr. Greg Hundley: Very nice. So now listeners, we're going to turn to our associate editor. One of the imaging experts here at Circulation, Dr. Victoria Delgado. Victoria, you see a lot of papers come across your desk and as an imaging expert, what attracted you to these two papers? And what do you think are their significance? Dr. Victoria Delgado: Thank you, Greg. I think that these two papers are important because right now, if we follow the clinical guidelines, we decide implantation. For example, of an ICD based on the ejection fraction, and we see that in many patients based on ejection fraction, they may not benefit ever from an ICD because they don't have arrhythmias. What other patients who do not meet the criteria often injection fraction below 35%. They may have still arrhythmias. So the article by Igor highlights the relevance of the amount of burden of late government Huntsman with CMR, in patients with non ischemic cardiomyopathy, which are sometimes very challenging patients on how to decide when we implant an ICD or not. We need sometimes to base the decision on genetics. Dr. Victoria Delgado: If we have an on the other hand, the paper of Pasquale, these were patients with normal echocardiogram. So what patient, having arrhythmias where we don't see on echocardiogram, that is the first imaging technique that we usually use to evaluate these patients. We don't see anything, but CMR can give us more information in terms of structural abnormalities and particularly not only the burden of scar, but also the pattern of the scar. And we have seen in other studies that for example, not only for ICD implantation, but for ventricular tachycardia ablation. The characteristics of that scar and some areas where these are short of panel that can be targeted for that ventricular tachycardia ablation can lead to much more precise treatment if you want of these patients. Dr. Greg Hundley: Thank you, Victoria. So it sounds like listeners we're hearing late gadolinium enhancement, regardless of EF could be forecasting, future arrhythmic events. And then also the pattern of late gadolinium enhancement, where contiguous segments in a ring-like fashion may also offer additional prognostic information. Well, now we're going to turn to our editorialists and as you know, listeners at Circulation, we'll bring in an editorialist to really help put things together and uniquely here today, we have Dr. Mark Estes, who is really not an imager per se, but like many of us uses the information from imaging to make clinical decisions. Mark, how do you see this late gadolinium enhancement as perhaps a new consideration for placement of devices? Dr. N.A. Mark Estes: Greg, that's one of the key questions. There's no doubt, not only based on these two studies, which extend our prior information about LGE and patients with valid and non ischemic cardiomyopathies that scar burden is important in predicting not only total mortality, but arrhythmic events. All of the criteria that were used in the original ICD studies, which include the definite, the Skuid half Danish and made it our it trials use only ejection fraction and functional status, no imaging. These are legacy trials. Now, many of them, a decade or more older. And the treatment of advanced heart failure has progressed to the point that the total mortality is dramatically lower than it was at the time of these studies. In some instances down to 4 or 5% per year. The studies are important in that they identify a subgroup of patients with low ejection fractions, less than 35%, who might qualify for ICDs, who are unlikely to benefit. Dr. N.A. Mark Estes: They also identify a group of patients with preserved ejection fraction greater than 35%, less than 50 in whom the risk of sudden death may be substantial. And it extends prior observations about patchy, mid Meyer, cardio wall fibrosis, subendocardial, subepicardial and important ways. But the key issue here, and it was alluded to with Pasquale's comments about prospective validation, is that when one has a risk stratifier and identifies a high risk population that has to be linked to an unequivocal therapy, it improves survival. And we don't have that link quite yet. Dr. N.A. Mark Estes: Prospective randomized trials are unlikely to be done in the low ejection fraction because they would probably be considered unethical. Given the trials that have shown the benefit you can't randomize to defibrillator versus an implantable loop recorders. I think the future really lies in risk stratification for people with preserved ejection fractions greater than 35%, less than 50 using LG in that patient population. Currently, I think the best information we can give to clinicians is to stick with the AHA guidelines, which is PF less than 35% with dilated, nonischemic class II symptoms who have had optimal medical therapy for at least three months using perhaps in that patient population LGE for shared decision-making in patients about the magnitude of the risk. And I think that's as far as we can go pending future studies, and there is one which we can discuss later on the CMR study at just that preserved ejection fraction LGE randomizing to defibrillator versus ILR. Dr. Greg Hundley: Thank you, Mark. So listeners just really quickly, let's go back to each of our experts and ask them, you know, in 20 seconds, Igor, Pasquale, Victoria, and Mark, what's the next study that needs to be performed in this space? Igor, we'll start with you. Dr. Igor Klem: Well, number one, following on Mark's comment on the less than 35% population, I think that it's unlikely that they're randomized clinical trial is ethical in this population, but we may consider a wealth of registry data by now that shows that there is a subgroup of patients who have a lower risk or lower benefit from an ICD. I think in the preserved ejection fraction above 35%, maybe up to 45%, 50%. That's an interesting study that's coming up. Maybe there's more trials that can provide us that robust information that we need today in order to change the guidelines to risk stratify, not based on the LVF, but on the presence of scar or maybe subgroups of scar. Dr. Greg Hundley: Pasquale? Dr. Pasquale Santangeli: Yes. So I think of course, one of the major studies is the one already alluded by this, which is a prospective study that links as specific therapy like ICD or even additional risk factors like we've been using program's stimulation some of these patients to further risk for the five to see what they can benefit. Dr. Pasquale Santangeli: Based another one that I think is important for the study that we did is a mechanistic more study to understand why the ring light pattern was there, as opposed to other patterns. We do believe we think that some of these patients may have an initial form of lb dominant arrhythmogenic paramount. There wasn't really a detective before and ran. Now, if we actually extending our study and have a registry to try to screen also the family members or patients with ring light pattern to understand whether there is a familiar component to it, because really we do not see this type of pattern that commonly and it'd been associated with lb dominant. Magnetic kind of alpha in some others, small studies. Dr. Pasquale Santangeli: So that's the other part to dig in a little bit more into the field type for these patients to understand why one pattern versus another happens and whether that gets main to, to explain why there's a higher risk in one population versus another. Dr. Greg Hundley: Victoria. Dr. Victoria Delgado: Yeah. Following what has been said. I think that from the imaging point of view, we are always criticizing in a way that we increase the burden or the cost of healthcare. But I think that these studies or any randomized study where MRI or echo is used in order to design a therapy and show the value of using that imaging technique to optimize the health care costs is important. So I will not add much on which sort of populations, but probably patients within non ischemic cardiomyopathy with preserved ejection fraction that do not fulfill the recent scores, for example, in hypertrophic cardiomyopathy to be implanted with an ICD. But probably if we see a lot of scar on a AGE where specific patterns that can help to decide which are the patients that have benefited from an ICD implantation, for example. Dr. Greg Hundley: Thank you. And finally Mark. Dr. N.A. Mark Estes: But I think all the major points have been hit here. And unfortunately we have a bit of a dilemma. And that dilemma is that these legacy trials for ICDs, which selected based on low ejection fraction and functional class II were done at a time when contemporary heart failure treatment was not as good as it currently is pharmacologically. And it's been reflected with a lower total mortality. When the mortality in this patient population gets down to the 4 and 5% per year, it's unlikely that any intervention for prevention of sudden death is going to impact on that total mortality. Dr. N.A. Mark Estes: So I do think that the registries hold a lot of promise, giving us insights into the subgroup of patients that previously would have been selected for defibrillators who may not have as much benefit or who may benefit the most. And I think that they will play an important part in perhaps refining the risk stratification with greater sensitivity and specificity in the patient population, less than 35%. I think the CMR guide trial is going to be a critical trial and looking at ICDs in the patient population between 35 and 50%, but we need to be mindful of one thing. And that in the Danish trial, they get a sub study looking at about 240 patients using LGE. And they found that ICD in patients with LGE that was positive, did not make a difference in survival or total mortality. So again, we need to get the data. I think the best clinical practice has come out of the best clinical evidence. You'll clearly be limitations to what we can do, but I think in the future, we'll have much better data to make these judgment calls. Dr. Greg Hundley: Very good. Well listeners, we want to thank our panelists, Dr. Igor Clem, Pasquale, Santangeli, Victoria Delgado, and Dr. Mark Estes for this wonderful discussion related to magnetic resonance imaging, late gadolinium enhancement, and how it may be useful in identifying those at risk for future arrhythmic events. On behalf of both Carolyn and myself, want to wish you a great week and we will catch you next week on the run. Dr. Greg Hundley: This program is copyright of the American Heart Association, 2021.  

Listen as Dr. Gary Dhillon presents on Long QT syndrome and pearls for anesthesiologists and intensivists. Initial publication: February 9, 2021. Please visit: www.openpediatrics.org OPENPediatrics™ is an interactive digital learning platform for healthcare clinicians sponsored by Boston Children's Hospital and in collaboration with the World Federation of Pediatric Intensive and Critical Care Societies. It is designed to promote the exchange of knowledge between healthcare providers around the world caring for critically ill children in all resource settings. The content includes internationally recognized experts teaching the full range of topics on the care of critically ill children. All content is peer-reviewed and open access-and thus at no expense to the user. For further information on how to enroll, please email: openpediatrics@childrens.harvard.edu

We're rebroadcasting one of our earlier episodes in honor of the long-awaited publication of The Mirror & the Light, author Hilary Mantel's final chapter of the trilogy she began with her peerless, Booker Prize-winning novels, Wolf Hall and Bring Up the Bodies. We found this story in her often wicked short story collection The Assassination of Margaret Thatcher.  “The Long QT” features a standard, modern-day dilemma that delivers an entirely unexpected sort of fright at the end. Host Aparna Nancherla chats with champion open water swimmer, Lynne Cox, a real life survivor of the disorder Mantel's story is based upon. Read by actress Joanne Whalley.

Here is the JournalFeed Podcast for the week of April 6-10, 2020. We cover LOCO2 - liberal vs conservative oxygen in ARDS; cefepime-associated neurotoxicity; a point/counterpoint on need for POCUS credentialing; and a better way to spot long QT. Special thanks to Lara Fesdekjian for writing theme music!

Dr Paul Wang:                   Welcome to the monthly podcast, On the Beat for Circulation: Arrhythmia and Electrophysiology. I'm Dr Paul Wang, editor in chief, with some of the key highlights from this month's issue.                                                 In our first paper, in a single‐center observational cohort study, Owen Donnellan and Associates compared arrhythmia recurrence rates in morbidly obese patients who underwent prior bariatric surgery, with those of non-obese patients following atrial fibrillation ablation. In addition to morbidly obese patients who did not undergo bariatric surgery, they matched 51 morbidly obese patients' body mass index, 40 kilograms per meter squared, who had undergone prior bariatric surgery in a two to one manner with 102 non-obese patients, and 102 morbidly obese patients without bariatric surgery on the basis of age, gender, and timing of atrial fibrillation ablation. From the time of bariatric surgery to ablation, bariatric surgery was associated with a significant reduction in BMI. 47.6 to 36.7 and reduction in systolic blood pressure, 145 to 118, P < 0.001.                                                 During a mean follow up of 29 months following ablation, recurrent arrhythmia occurred in 10 out of 51 or 20 patients in a bariatric surgery group, compared to 25 out of 102 patients, 24.5% in a non-obese group, and 56 out of 102 or 55% in the non-bariatric surgery morbidly obese group. No procedural complications were observed in the bariatric surgery group. In our next paper, Martin Andreas and Associates examined whether noninvasive, low-level, transcutaneous electrical stimulation of the greater auricular nerve reduced the risk of postoperative atrial fibrillation, in a pilot of patients undergoing cardiac surgery. After cardiac surgery, electrodes were applied in the triangular fossa of the ear. Stimulation, amplitude 1-million-amp frequency, one Hertz for 40 minutes, followed by a 20-minute break, was performed for up to two weeks after cardiac surgery. Patients were randomized into sham, N equals 20 or treatment group, N equals 20, for low- level, transcutaneous electrical stimulation. Patients receiving low-level, transcutaneous stimulation had a significant reduced incidence of postoperative atrial fibrillation. Four out of 20, compared to controls 11 out of 20. P equals 0.02.                                                 The median duration of postoperative atrial fibrillation was comparable between the treatment group and control group. No effect on low-level stimulation on CRP or IL-6 levels was detectable. In our next paper, Kazuki Iso and Associates examine whether the vagal response phenomenon is common to patients without atrial fibrillation. Continuous, high- frequent stimulation of the left atrial ganglion and plexus was performed in 42 patients, undergoing ablation for atrial fibrillation. In 21 patients undergoing ablation for left-sided accessory pathway, the high frequency stimulation, 20 Hertz at 25 milliamps of 10 millisecond pulse duration, was applied for five seconds at three sites within the presumed anatomical area of each of the five major left atrial ganglion plexus, for a total of 15 sites per patient. The authors define vagal response to high frequency stimulation, as prolongation of the R interval by > 50% in comparison to the mean pre-high-frequency stimulation RR interval, average over 10 beats.                                                 In active ganglion plexus areas, is areas in which vagal response was elicited. Overall, more active ganglion plexi or GP areas were found in the atrial fibrillation group patients, than in the non-atrial fibrillation group patients. And in all five major GPS, the maximum R interval during high-frequency stimulation was significantly prolonged in atrial fibrillation patients. After multivariate adjustment, association was established between the total number of vagal response sites and the presence of atrial fibrillation. The authors concluded that the significant increase in vagal responses elicited in patients with atrial fibrillation, compared to responses in non-atrial fibrillation patients, suggests that the vagal responses is to hypercan stimulations, reflect an abnormally increased ganglion plexi activity, specific to atrial fibrillation substrates.                                                 In our next paper, Vidal Essebag and Associates combine the data from the Bruise Control One and Two studies to evaluate the effect of concomitant antiplatelet therapy on clinically significant hematomas, and to understand the relative risk of clinically significant hematomas in patients treated with DOAC versus continued Warfarin. The Bruise Control study demonstrated that perioperative Warfarin continuation, reduced clinically- significant hematomas by 80%, compared to Heparin bridging. 3.5% versus 16%. Bruise Control Two observed a similarly low risk of clinically-significant hematomas when comparing continued versus interrupted direct oral anticoagulant. 2.1% in both groups. A total of 1,343 patients were included in Bruise Control One and Bruise Control Two, the primary outcome for both trials with clinically-significant hematomas. There are 408 patients identified as having continued either a single or dual antiplatelet agent at the time of device surgery. Anti-platelet use versus non-use was associated with clinically-significant hematomas in 9.8% versus 4.3%. P less than 0.001 and remained a strong independent predictor with multi-variate adjustment. Odds ratio 1.965, however, multivariate analysis adjusting for anti-platelet use, there was no significant difference in clinically-significant hematomas observed between direct oral anticoagulant use, compared with continued Warfarin.                                                 In our next paper, Markus Rottmann and associates examine the relationship between activation slowing during sinus rhythm, and vulnerability for reentry, and correlated the areas with components of the circuit. In a porcine model of healed infarction, of 15 swine, nine had inducible ventricular tachycardia, 5.2 per animal. While in six swine, VT could not be induced despite stimulation from four RV and LV sites at two drive trains in six extra stimuli down to refract refractoriness. Infarcts with ventricular tachycardia had a greater magnitude of activation slowing, during sinus rhythm, a minimal endocardial activation velocity cutoff, less than 0.1 meters per second. Differentiated inducible from non-inducible infarctions. P equals 0.15. Regions of maximal endocardial slowing during the sinus rhythm corresponded to the VT isthmus. Area under the curve equals 0.84 while bystander sites exhibited near normal activation during sinus rhythm. VT circuits were complex, with 41.7 exhibiting discontinuous propagation with intramural bridges of slow conduction in delayed quasi -simultaneous endocardial activation. Regions forming the VT isthmus borders had facts or activation during sinus rhythm, while regions forming the inner isthmus were activated faster during ventricular tachycardia.                                                 In our next paper, Mary Rooney and Associates sought to define the prevalence of subclinical atrial fibrillation in a community-based elderly population, and to characterize subclinical atrial fibrillation and the incremental diagnostic yield of four versus two weeks of continuous ECG monitoring. They conducted a cross-sectional analysis within the community- based, multi-centered observational atherosclerosis risk in communities. Erik Study, using visit five, 2016 to 2017 data. The 2,616 Erik Study participants who wore a lead-less ambulatory ECG monitor for up to two weeks were age 79 years, 42% men and 26% black. In its subset, 386 participants without clinically-recognized atrial fibrillation wore the monitor twice, each time for two weeks. They characterize the prevalence of subclinical atrial fibrillation, atrial fibrillation detected without clinically recognized atrial relation. Over two weeks of monitoring and the diagnostic yield of four versus two weeks, the authors found that the prevalence of subclinical atrial relation was 2.5%. the prevalence of subclinical each relation was 3.3% among white men, 2.5% among white women, 2.1% among black men and 1.6% among black women.                                                 Subclinical A Fib was mostly intermittent, 75%. Among those with intermittent subclinical atrial fibrillation, 91% had an AF burden of less than or equal to 10%, during the monitoring period. In a subset of 386 patients without clinical atrial fibrillation, 78% more subclinical atrial fibrillation was detected by four weeks versus two weeks of ECG monitoring. In this study, the prevalence of subclinical A Fib was lower than previously reported. And monitoring beyond two weeks provided substantial incremental diagnostic yield.                                                 In our next study, Rafael Ramirez and Yoshio Takemoto and Associates investigated arrhythmic mechanisms of Ranolazine in sheet models, in paroxysmal and persistent atrial fibrillation. Paroxysmal atrial fibrillation was maintained during acute stretch and persistent atrial relation was induced by long-term atrial tachypacing. Isolated Langendorff-perfused sheet parts were optically mapped. In paroxysmal atrial fibrillation, Ranolazine 10 micromolar reduced dominance frequency from 8.3 to 6.2 Hertz. P less than 0.01, before converting to sinus rhythm, decreased singularity point density for 0.07 to 0.039 and left atrial epicardium and prolonged atrial fibrillation cycling. Road or duration tip trajectory in variants of Afib cycle lengths were unaltered. In persistent atrial fibrillation, Ranolazine reduced dominance frequency, prolonged atrial fibrillation cycle length, increased the variance of atrial fibrillation cycling and had no effect on singularity point density, and failed to convert atrial fibrillation to sinus rhythm. Doubling the Ranolazine concentration or supplementing with Dofetilide failed to convert persistent atrial fibrillation to sinus rhythm.                                                 In computer simulations or rotors, reducing the sodium current decreased dominant frequency, increased tip meandering, and produce vortex shedding upon wave interaction with un-excitable regions. Thus, the authors concluded that paroxysmal atrial fibrillation and persistent atrial relation respond differently to Ranolazine. Cardioversion in the paroxysmal atrial fibrillation can be attributed partly to decrease dominant frequency and singularity point density and prolongation of atrial fibrillation cycling. In persistent atrial fibrillation, increased dispersion of atrial-like cycle length and likely vortex shedding, contributes to rotor formation, compensating for any rotor loss, and may underline the inefficacy of Ranolazine to terminate persistent atrial fibrillation.                                                 In our next paper, Pyotr Platonov and Associates assess the risk of atrial fibrillation and its relationship to Long-QT syndrome genotype, and the long-term prognosis in Long-QT syndrome patients. Genotype- positive patients with Long-QT syndrome. 784 with LQT1. 746 with LQT2, and 233 with LQT3, were compared with 2043 genotype-negative family members. In patients followed from birth to 60 years, LQT3 patients had an increased risk of atrial fibrillation compared to genotype-negative family members. Hazard ratio 6.62. While neither LQT1 or LQT2 demonstrated increased atrial fibrillation risk. After the age of 60 years, LQT2 patients had significant lower risk of atrial fibrillation compared with genotype-negative controls. Hazard ratio of 0.07. Atrial fibrillation was a significant predictor of cardiac events in LQT3 patients, through the age of 60. Hazard ratio, 5.38. The authors concluded that there's an increased risk of early-age atrial fibrillation in LQT3 patients and a protective effect of LQT2 genotype, resulting in a decreased risk of atrial fibrillation after the age of 60.                                                 In our next paper, Julia Ramírez and Associates evaluated the cardiovascular prognostic value of T-waves morphology restitution in 55,222 individuals undergoing an exercise stress test in the UK biobank, and identify any genetic contribution. They found that 1,743 or 3.2% of individuals had a cardiovascular event. T-wave morphology restitution during recovery from exercise was significantly associated with cardiovascular events. Hazard ratio 1.11. Independent of clinical variables and other ECG markers, T-wave morphology restitution during recovery from exercise was also associated with all-cause mortality. Hazard ratio 1.1. And ventricular arrhythmias, hazard ratio 1.16. They identified 12 genetic loci, in total for T-wave morphology restitution during exercise, in T wave morphology restitution during recovery, of which nine are associated with another ECG marker. Individuals with the top 20% of T-wave morphology restitution during recovery, genetic risk scores, were significantly more likely to have a cardiovascular in the full UK biobank. 5.3% than individuals in the bottom percent, a 20% hazard ratio of 1.07.                                                 We have two other research letters in a special report. Wassim Mosleh, Sharma Kattel report that Galectin-3 is a predictor of mortality after cardiac arrest. In the next research letter, Jerry Jez and Associates report on remotely-navigated ablations in ventricular myocardium, that result in acute lesion-size, comparable to force sensing manual navigation. In a special report, Sohaib Virk and Saurabh Kumar report on a meta-analysis of remote magnetic versus manual catheter navigation for atrial fibrillation ablation. That's it for this month. We'll hope that you'll find the journal to be the go-to place for everyone interested in the field. See you next time. This program is copyright, American Heart Association 2019.  

Darren Sudman, co-founder and CEO of Simon's Heart, discussed the non-profit's work in discovering hidden heart conditions and preventing deaths from Sudden Cardiac Arrest in children.  He related the story of son, Simon, who died at three months.  Unlike most cases of Sudden Infant Death Syndrome, the Sudmans learned what took their child's life - a genetic condition, Long QT.  Long QT syndrome  is a heart rhythm condition that can cause chaotic heartbeats that could trigger a sudden fainting spell or seizure. In some cases, it causes sudden death.  They also discovered that Simon's mother had the same condition.  They learned that apparently healthy children can have the condition, and that it's only when a youth athlete dies on the court or playing field that it's discovered.  The Sudmans formed Simon's Heart to raise awareness of the symptoms and to advocate for heart screenings for young athletes.  Simon's Heart works with school districts to offer free CKGs and other tests to kids before they participate in sports.  He explained that it takes a district of 2-3,000 students to organize a clinic as only 10% of parents take advantage of the offer. Mr. Sudman noted that many deaths, including drownings or single car accident deaths, could be undiagnosed cardiac incidents and he calls for better reporting to help researchers and to help survivors check other family members for a hidden defect.  He urges everyone to learn CPR, but notes you don't need a certificate to save a life, rudimentary chest compressions can keep someone alive until real help arrives.  Toward this Sion's Heart has created a ‘jukebox' of 100 beat per minute songs to help with emergency CPR.   They also have instructions to help communities, churches or groups crowd fund raise for AEDs which can be installed in a gym, rec center or school for as little as $900.    To learn more about Simons Heart go to simonsheart.org. See omnystudio.com/listener for privacy information.

In today’s episode, I interview Rachel March. Rachel shares the birth of her little boy and her twin girls. Falling pregnant at 21 Rachel admired she knew very little about pregnancy and birth she just knew she wanted to have a baby. None of her friend’s had had kids it was all very unknown. Rachel’s pregnancy was considered high risk due to the fact that she was born with a condition called Long QT syndrome. This condition affects Rachel’s heart and hearing. Rachel lost her job at 25 week due to unfair dismissal due to her pregnancy, a case she fought and won, however, it was a very stressful time. After having her little boy Rachel developed postnatal depression which she took medication for and saw a psychologist. To hear more about Rachel’s story tune into this weeks episode.

In Episode 135 of Keto Talk, Jimmy and Dr. Will Cole answer your questions about Age Considerations With Keto, Unexpected Weight Gain, Long QT, Intense Nausea, And Retaining Breast Enhancement Fat While Keto and more! HOT TOPICS: With the popularity of keto at an all-time high, it seems strange that the food companies keep pumping out new incarnations of crappy carbage How can you get a Freestyle Libre flash blood glucose monitor prescribed by a physician without being diagnosed as a Type 2 diabetic? Can going keto be a part of the healing process from Grave’s Disease? What role does keto specifically play in helping to “blow out the SIBO” as Will as described it on a previous episode? Why would skin get more sensitive and even develop eczema once you get keto-adapted? What role does a low-carb, high-fat, ketogenic lifestyle play in dealing with the inflammatory condition known as hyperhomocystinemia? HEALTH HEADLINES: Finnish Doctor Persecuted For His Book: A Life Without Drugs Keto diet: High in fat and popularity, but is it healthy and sustainable? Inside the Rise of Keto: How an Extreme Diet Went Mainstream 12 Keto-Friendly Foods That Aren't As Low-Carb As You Think The keto diet was accidentally discovered in 1862 by a funeral director who lost 52 pounds on a diet of cordial and meat STUDY: Fasting Appears to Reset "Crucial" Clock on Aging-Related Diseases  – DIRECT LINK TO PAPER: Fasting Imparts a Switch to Alternative Daily Pathways in Liver and Muscle Jimmy and Will answer your questions: - Are there age and gender specific considerations with keto to be aware of? Hi Jimmy and Will, Several months ago my elder sisters (71 and 72 years old) started keto after seeing how well it worked for me (I'm quite a bit younger at 57). They're well on their way to their weight loss goals but they've recently noticed there might be some age-related and gender-related considerations for women who are 70+ years of age. Would you guys talk about some of these things they should be thinking about? Thank you! Carolyn – What can be done about unexpected weight gain while in nutritional ketosis? Are my hypothyroid and pain medications making things more challenging for me? Dear Jimmy and Dr. Cole, I listen regularly to Keto Talk and I'm grateful for all of your valuable information. I’m 5’6” tall and weigh 179 pounds as a 61 years old woman and have been keto for a couple of years. I started eating this way when my family doctor suggested I may be pre-diabetic with a fasting blood glucose of 101. My blood ketones remain in the 1.5-2.0 range, so I know I’m burning fat. Initially I lose 55 pounds, but for some strange reason I gained back 10 pounds. Although I have a function medicine medical doctor, she’s no fan of me trying longer fasts because of my hypothyroid issues which I take Armour thyroid for. I’ve tried changing things up in the way I’m doing keto, including a protein sparing modified fast with significantly less fat than I typically eat and carnivore. These did help me lose some weight, but both gave me problems and the weight I lost came right back on with my regular keto diet. I am currently preparing for a women's mini-triathlon (1.5 mile kayak, 11-mile bike, and 3.1 mile walk or run) which takes place in February. I did this last year in a fasted state and did great! I feel like that's not going to be the case this time around. I'd like to at least remain keto but I’m thinking being mostly carnivore is where I feel my best. I will add that my doctor prescribed me Gabapentin 100mg for me to take at night to help with pain that interferes with my sleep. Do I need to add in additional carbs to what I’m doing to help with these issues or should I be concerned? Thanks, Colleen – Are there any specific alterations to keto for people dealign with the condition known as Long QT? Hi Jimmy and Dr. Cole, I am a huge fan of your podcast and listened to all of them in double time so I could digest all the information faster (I especially liked the Poopcast and now I refer to Will as Dr. Pooptacular!). In the earlier episodes I was listening to, Dr. Nally mentioned that Long QT is a reason to be monitored by your doctor when starting keto. This piqued my interest since I deal with this condition. I have an implanted heart monitor that checks for abnormal rhythms 24/7, so I’m assuming that would catch any issues. Are there any specific precautions I should be taking with long QT and keto (mine is the incredibly rare genetic variant, Long QT type 10, which has to do with a sodium channel pathway and is most similar to Type 3 of the more commonly known types). Signed, your healthiest chronically ill Ketonian, Jess – How can someone overcome intense nausea while on a ketogenic diet? Hi Jimmy and Will, I am a naturopath in Australia and I have been keto for a few months. I had a fairly easy adaptation but my partner is now having a lot of nausea. He started a couple of weeks ago and got into ketosis in about 48 hours with blood ketones around 1.2. He was doing so well until I made the mistake of giving him some cake I had made with almond and coconut flour. He almost immediately started feeling sluggish and experienced mental fatigue and fogginess as his blood ketones crash to under 0.5. He was able to get back into ketosis again, but the nausea and other side effects have been relentless ever since. We’ve been adding in more salt to try to help, but nothing is helping so far. I feel like I broke the momentum he had on his keto and would love any suggestions about how to help him get back on track again. He came to keto from a mostly fruit-based diet for a year prior to this. I feel my partner has so much to gain from eating this way coming from a history of chronic fatigue! Thanks for your help, Jodi KETO TALK MAILBOX –  Are there concerns with the inability to retain transferred breast enhancement fat for someone who is eating a ketogenic diet? Hello Jimmy and Dr. Cole, I am looking to have liposuction to transfer the fat to my breasts for a natural breast enhancement after going through breastfeeding and experiencing a nice weight loss thanks to keto. Will ketosis compromise my body’s ability to retain the fat that is transferred as it needs to establish a new blood supply to be able to live in the new location. I am currently at my goal weight and am no longer losing weight. My initial thought is that since ketosis is a healthy state for the body to be in, it should not be a problem. But what say you?  

Jane Ferguson:                Hello, welcome to Getting Personal: Omics of the Heart, Episode 22. This is a podcast from Circulation: Genomic and Precision Medicine, and the AHA Council on Genomic and Precision Medicine. I am Jane Ferguson and it's November 2018.                                            Our first article comes from Carlos Vanoye, Alfred George and colleagues from Northwestern University Feinberg School of Medicine and is entitled, High Throughput Functional Evaluation of KCNQ1 Decrypts Variance of Unknown Significance.                                            So a major growing problem in clinical genomics is that following the identification of a variant that is potentially linked to a disease phenotype, without further interrogation, it's really hard to make sense of the functional significance of that variant. Right now, the large number of variants of unknown significance lead to confusion for patients and clinicians alike. To allow for accurate diagnoses and the best treatment plans, we need a way to be able to screen variants to assess their function in a fast and cost-effective manner.                                            In this paper, the authors decided to focus in the KCNQ1 gene, a cardiac ion channel, which can affect arrhythmias. They aim to assess whether a novel high-throughput functional evaluation strategy could identify functional mutations, as well as an in vitro electrophysiological approach. Which is effective, but expensive and time-consuming. Their approach capitalized on an existing automated electrophysiological recording platform that had originally had been developed for drug discovery essays.                                            They selected 78 variants in KCNQ1 and assessed their function using the High-Throughput platform, which coupled high efficiency, cell electroporation with automated plain or patch clamp recording. They compared the results to traditional electrophysiological essays and find a high rate of concordance between the two methods. Overall, they were able to reclassify over 65% of the variants tested, with far greater efficiency than traditional methods.                                            While this method will not work for all genes and phenotypes, the authors have demonstrated an efficient method for functional interrogation of variants. Which may greatly accelerate discovery and conditions such as Long QT or other congenital arrhythmias.                                            The next paper, Nocturnal Atrial Fibrillation Caused by Mutations in KCND2 Encoding Poor Forming Alpha Subunit of the Cardiac KV 4.2 Potassium Channel, comes from Max Drabkin, Ohad Birk, and colleagues at Soroka University Medical Center in Israel. This paper also focuses on cardiac ion channels and the role of mutations in atrial fibrillation.                                            In a family with early-onset peroxisomal AF across three generations, whole XM sequencing revealed a variant in KCND2 encoding the KV 4.2 Potassium Channel, which segregated consistent with autosomal dominant heredity. This variant resulted in a replacement of a conserved [inaudible] residue with an arginine. To investigate functional consequences of this novel variant, they conducted experiments in xenopos laevis oocytes and found that there is decreased voltage depended channel and activation and impaired formation of the KV 4.2 Homotetramer and the KV 4.2, KV 4.3 Heterotetramer.                                            Overall, this study shows that a novel mutation in a conserved Protein kinase C Phosphorylation site within the KV 4.2 Potassium Channel underlies the phenotypes observed in a family of peroxisomal atrial fibrillation. The targeting Atrial KV 4.2 might be an effective therapeutic avenue.                                            Next up, Michael Levin and Scott Damrauer and colleagues from the University of Pennsylvania published an article entitled, Genomic Risks Stratification Predicts All-Cause Mortality After Cardiac Catheterization.                                            They were interested in understanding the utility of polygenic risk scores for disease prediction. They constructed a genome Y genetic risk score for CAD and applied it to individuals from the Penn Medicine Bio-bank who had undergone Coronary angiography and genotyping.                                            They included over 139,000 variants for the 1,500 ancestry subjects who were included and classified them as high or low polygenic risk. Individuals who were classified as high polygenic risk were shown to have higher risk of All-Cause mortality than low polygenic risk individuals despite no differences in traditional risk factor profiles. This was particularly evident in individuals with high genetic risk but no evidence of angiographic CAD.                                            Adding the polygenic risk score to a traditional risk assessment model was able to improve prediction of five year All-Cause mortality. Highlighting the utility of a polygenic score and underscoring traditional risk factors do not yet fully capture mortality risk.                                            The next article entitled, "Bio-marker Glycoprotein Acetyls is Associated with the Risk of A Wide Spectrum of Incident Diseases and Stratifies Mortality Risk in Angiography Patients" comes from Johannes Kettunen, Scott Ritchie, Peter Würtz and colleagues from the University of Oulu Finland.                                            GlycA is a circulating biomarker that reflects the amount of Glycated proteins in the circulation. It has been associated with cardiovascular disease, Type 2 Diabetes, and all-cause mortality. In this paper, the authors used electronic health record data from over 11,000 adults from the finish general population previously included in the "FINRISK" and "Dilgom" studies and they tested for a associations between GlycA and 468 different health outcomes over an 8-12 year follow up. They report new associations between GlycA and multiple conditions including incident alcoholic liver disease, chronic renal failure, glomerular diseases, chronic obstructive pulmonary disease, inflammatory polyarthric disease and hypertension.                                            These associations held true even after adjusting for CRP suggesting that GlycA represents an independent biological contributor to inflammation and disease. Their findings highlight potential utility for GlycA as a biomarker of many diseases and underscore the importance future functional and mechanistic studies to understand how GlycA is linked to disease risk.                                            Our last original research article entitled, "Tissue Specific Differential Expression of Novel Jeans and Long Intergenic Non-coding RNAs in Humans with Extreme Response to Endotoxic glycemia comes from Jane Ferguson, Murdock Riley, and colleagues from Vanderbilt University, Columbia University, and the University of Pennsylvania. That first author is none other than me, so I'm not unbiased reader of this particular manuscript, but I'd like to tell you a little bit about it anyway.                                            We were interested in understanding the transcriptional changes that occur in tissues during acute inflammation. As part of the genetics of evoked responses to Niacin and Endotoxemia, or gene study, we recruited healthy individuals and performed an inpatient endotoxin challenge where we administered a low dose of LPS and looked at the systemic inflammatory response. Individuals vary greatly in the degree of their inflammatory response to LPS and we identified high and low responders, men and women, of African and European ancestry, who had responses in the top or bottom 10% for cytokines and fever.                                            We conducted RNA seek and adipose tissue in 25 individuals and CD-14 positive monosites for 15 individuals in pre and two or four hours post LPS samples. We found that the differences in transcriptional response between high or low responders are mostly explained by magnitude rather than discrete sets of genes.                                            So some core genes were altered similarly, in both groups, but overall the high responders mounted a large transcription of response to LPS or low responders rather than mounting an anti-inflammatory response actually just barely responded on the transcription level. We saw clear tissue specificity between manosites and adipose tissue we identified several long non-coding RNAs that were up or down regulated in response to LPS and validated these independent samples one of these link RNAs which we have now named Monosite LPs induced link RNA regulator vile six or Mahler Isle six, with highly regulated by LPs and monosites but not in adipose tissue.                                            We [inaudible] THP-1 monosites and find a significant effect on iOS six expression suggesting that this is a novel link RNA that regulates Isle six expression in manosites potentially through a cd-86 dependent pathway. Overall our data revealed tissue specific transcriptional of changes that correlate with clinical inflammatory responses and highlight the role of specifically incarnate and inflammatory response.                                            Next up is a research letter entitled "Reduced Sodium Current in Native Cardiomyocytes of a Regatta Syndrome Patient Associated with Beta Two Central Mutation" published by Constance Schmidt, Felix Wiedmann, Ibrahim El-Battrawy, Dierk Thomas, and co-authors from University Hospital Heidelberg. They obtained cardiomyocytes from a patient with Regatta Syndrome previous whole XM sequencing had implicated a variant in the Beta Two Syntrophin or "SNTB2" gene as potentially causal in this individual. Expression analysis showed lower SNTB2 expression and atrial tissue of the affected individual compared with controls.                                            They performed electrophysiology on the Microcytes and found reduced peak sodium density and reduced late sodium current. They co-express wild type or mutant SNTB2 in heck 293 T cells and [inaudible] with the cardiac sodium channel NAV-1.5 and found a significant effect on binding which adversely affected sodium currents. This study nicely demonstrates the functional effect of this SNTB2 mutation underlying Regatta Syndrome in this patient.                                            A second research letter comes from A.T. van den Hoven and Jolien Roos- Hesselink and colleagues from Erasmus University Medical Center in the Netherlands and is entitled "Aortic Dimensions and Clinical Outcome in Patients with SMAD three mutations, they were interested in understanding how the Aortic dilation comment individuals with SMAD three mutations compared to individuals with other syndrome and causes of Aortic dilation.                                            In 28 patients with SMAD three mutations, there were significant growth in the Sinotubular Junction the ascending Aorta on the diaphragm over an average of 10 years of follow up at reads far higher population averages but lower than might be seen in other syndromes, such as [inaudible]. Intensive management and preventive surgery and many of the patients prevented any mortality in this group.                                            Rounding out this issue is a clinical letter entitled "Concealed Arrhythmogenic  Right Ventricular Cardiomyopathy in Sudden unexplained Cardiac Death events from Jodie Ingles, Chris Semsarian, and colleagues from the University of Sydney, Australia. They report on for clinical cases where individuals presented in early adulthood with unexplained cardiac arrest, which was later found to be attributable to mutations in the PKP2 gene. PKP2 or, Plakophilin 2, encodes an integral component of the Desmosome, which is important and Cell-Cell adhesion. Further PKP2 is involved in transcriptional activation of genes controlling intracellular calcium cycling. This gene has been implicated arrhythmogenic right ventricular cardiomyopathy in individuals with cardiac structural abnormalities. These four cases where unrelated individuals were all fans to have loss of function variants and PKP2 underlying sudden cardiac death or events, despite structurally normal hearts. This prompts questions on the clinical management of such cases of concealed ARVC.                                            That's all from us for November, thanks to all of you out there listening. We'll be back in December for the final episode of 2018.                                            This podcast was brought to you by Circulation Genomic and Precision Medicine and the American Heart Association Council on Genomic and Precision Medicine. This program is copyright American Heart Association 2018.                                             

Dr Paul Wang:                   Welcome to the monthly podcast On the Beat, for Circulation: Arrhythmia, and Electrophysiology. I'm Dr Paul Wang, editor-in-chief, with some of the key highlights from this month's issue.                                                 In our first paper, Elizabeth Saarel and associates describe the analysis of athletes in the ICD sports registry. The authors found that over a median follow-up of 42 months of 129 young athletes, and a mean age of 16 years, there were 35 athletes, or 27%, that received a total of 38 shocks. Long QT syndrome and hypertrophic cardiomyopathy were the most common diagnoses. While shocks related to competition and practice were not uncommon, there were no serious adverse sequelae. Lead malfunction rates were similar to previously reported in an unselected pediatric ICD populations. There were no occurrences of death, arrest, injury related to arrhythmia during sports. There was one ventricular tachycardia ventricular fibrillation storm during competition.                                                 In our next paper, Kedar K. Aras and associates theorize that the tissue volume to wavelength volume ratio is important in determining ventricular fibrillation sustainability. They perform panoramic optical mapping of coronary perfused human left ventricular wedge preparations, which were subjected to acts of potential duration changes produced by IK,ATP agonist pinacidil and antagonist glybenclamide. They found that pinacidil and escalating concentrations progressively decreased the volume wavelength in ventricular fibrillation became sustained when the tissue volume to wavelength ratio was above the safety factor, K equals 4.4. In addition, ventricular fibrillation was only sustained when the ventricular volume exceeded the critical wavelength volume defined by the product of pacing cycle wave length in the longitudinal transverse and transmural directions.                                                 In our next paper Thomas Deneke and associates examine the ability of a novel infrared thermal probe to predict endoscopically detected thermal esophageal lesions post atrial fibrillation ablation. They studied six patients undergoing their first pulmonary vein isolation, using radio frequency point by point catheter ablation in the HEAT-AF study; 12 or 19% of patients had endoscopically detected thermal esophageal lesions. The peak esophageal temperature Tpeak was significantly higher, 56.3 degrees Celsius versus 45.7 degrees Celsius. P less than 0.0001 in patients with endoscopically detected thermal esophageal lesions compared to those without lesions. Logistical regression analysis demonstrated Tpeak was a statistically significant predictor, P equals 0.0008 pf endoscopically detected thermal esophageal lesions with an odds ratio of 1.52.                                                 In our next paper Dian Cheng and associates examine a novel algorithm incorporating right precordial and posterior leads to discriminate between left ventricular outflow tract and right ventricular outflow tract foci. The V3R to V7 index was prospectively tested in consecutive patients at four centers. In 94 patients of the validation cohort with 79% RVOT foci, a QS pattern in lead V3R exclusively recorded in right ventricular outflow tract foci, while an S wave in V3 was exclusively recorded in left ventricular outflow tract foci. The V3R to V7 index of LVOT origin was significantly great than that of RVOT 1.05 versus 0.28 P, less than 0.001 with a V3R to V7 index of greater than equal to 0.85 predicting an LVOT origin with 87% sensitivity and 96% specificity. With the V3R to V7 index of 0.85 or greater RVOT origin could be excluded with 98.6% accuracy.                                                 In the next paper Jim Cheung and associates examine the in-hospital outcomes, cause, and thirty-day readmissions following catheter ablation of MI associated ventricular tachycardia. The authors use a nationwide readmissions database to evaluate 4109 admissions for catheter ablation of MI associated ventricular tachycardia occurring between 2010 and 2015. The index admission in-hospital mortality rate was 2.7% and the procedural complication rate after ventricular tachycardiablation was 11.5%. Pulmonary hypertension, lung disease, obesity and coagulopathy were independent predictors of mortality. Following discharge after VT ablation the thirty-day readmission rate was 19.2%. With the median time to readmission of 10.0 days, in an in-hospital mortality of 2.9%. Cardiac causes accounted for 74% of readmissions. With ventricular tachycardia accounting for 41% of admissions and congestive heart failure accounting for 14% of readmissions. Pulmonary hypertension, congestive heart failure, smoking, chronic pulmonary disease, and prolonged index hospitalization were significant independent predictors of thirty-day readmission. After adjustment thirty-day readmissions were associated with a 38.9% increase in cumulative hospitalization costs.                                                 In the next paper Tomofumi Nakamura and associates examine the relation of hemorrhagic and thromboembolic events with anticoagulations strategy in the setting of epicardial axis procedures for ventricular arrhythmia mapping and ablation. In 355 patients oral anticoagulants were stopped perioperatively in heparin administered prior to the procedure. The patients were divided to three groups per the anticoagulations strategy. Group 1, no heparin was administered before pericardial access, Group 2, heparin was administered in reverse before pericardial access, and Group 3 heparin was administered and not reversed. Significant pericardial bleeding defined is greater than 80 milliliter occurred in 46 cases or 13% and did not differ among the three groups. Unintentional cardiac puncture in left ventricular chest infraction less than [inaudible 00:07:32] 35% were independently associated with pericardial bleeding with an odd ratio of 16.4 or 2.28. Of 38 procedures with unintentional cardiac puncture there were no differences in pericardial bleeding for different anti-coagulant strategies. Thromboembolic events occur in 5 patients, 1 coronary embolism, 1 stroke, 2 deep vein thrombosis, and 1 fatal pulmonary embolism and 1 thrombus on a temporary ventricular assist device.                                                 In the next paper, Elisabeth Mouws and associates examine whether the combination of lines of conduction block with multiple wave fronts at the pulmonary vein area may result in increased arrhythmogenicity and susceptibility to atrial fibrillation. The author performed intra-operative high-density epicardial mapping of pulmonary vein area and is 450 sites with an intra-electrical distance of 2 milliliters which performed during sinus rhythm in 327 patients. With and without preoperative intra-fibrillation. Excitation of the pulmonary vein area occurred via multiple consecutive wave fronts in the vast majority, 81% of patients. In total 561 wave fronts were observed which propagated through the septal or paraseptal regions tore the pulmonary vein area in 82%. Substantial dissociation of consecutive wave fronts was observed with delta activation times of 10.6 milliseconds. No difference was observed in delta activation times of consecutive wave fronts during sinus rhythm between patients with and without atrial fibrillation. In excitation-based risk factor model including conduction delay of greater equal to 6 millimeters conduction block of greater than or equal to 6 millimeters and conduction delay conduction block of 16 millimeters or greater, wave fronts vie the posterior inferior and posterior superior in multiple opposing wave fronts demonstrated a 5-fold risk of atrial fibrillation when multiple risk factors were present.                                                 In our final paper Yoshitaka Kimura and associates examine the prognostics significance of PR interval prolongation on adverse cardiac events. They studied 176 patients with repaired tetralogy of flow with a median age of 17.4 years then they evaluated their correlation with right ventricular volume and function measured by cardiac magnetic resonance and the significance as a risk factor of adverse cardiac events were ventricular arrhythmias, atrial arrhythmias, heart failure, hospitalization, complete AV block, and all cause death. First degree AV block was noted 25 patients or 14% during a median follow-up of 10 years there was a progressive prolongation of PR interval 2.0 milliseconds per year. Importantly there were significant correlations between PR interval prolongation and right ventricular enlargement or right ventricular disfunction. In contrast, patients who underwent pulmonary valve replacement, N equal 23, significant shortening of PR interval was noted, 204 versus 176 milliseconds, P equals 0.007. Cox regression analysis showed that the first degree AV block was an independent risk factor for ventricular arrhythmias hazard ratio 5.479, in complete heart block, hazard ratio 27.67, and it had a tendency for heart failure hospitalization, hazard ratio 3.3. In addition PR interval prolongation greater than 2 millisecond per year was also a significant risk factor for ventricular arrhythmias regardless of the presence or absence of first degree AV block in enrollment.                                                 That's it for this month. We hope that you will find the journal to be the go to place for everyone interested in the field. See you next time.

Dr Carolyn Lam:                Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.                                                 Is there a unique lipoprotein profile for incident peripheral artery disease as opposed to coronary or cerebral vascular disease? Well, you're just gonna have to wait for our feature discussion to find out. That's coming right up after these summaries.                                                 Our first original paper this week tells us that gene variance known to be associated with idiopathic and peripartum cardiomyopathy are also associated with preeclampsia. First and corresponding author Dr Gammill from University of Washington and colleagues studied 181 participants with confirmed preeclampsia from the Preeclampsia Registry in BioBank. Saliva samples were collected for DNA isolation and whole exome sequencing was performed to detect rare variants in 43 genes known to be associated with cardiomyopathy.                                                 Results were compared with data from two controlled groups, unrelated women with a gynecological disorder, sequence using the same methods and instruments, as well as published variant data from 33,000 subjects in the Exome Aggregation Consortium.                                                 The results showed that women who developed preeclampsia are more likely to carry protein altering mutations in genes associated with cardiomyopathy, particularly, the TTN gene which encodes the sarcomeric protein titin. Thus, detecting these gene variants may allow more specific diagnosis, classification, counseling and management of women at risk.                                                 Prior trials have shown that nonsteroidal anti-inflammatory drugs or NSAIDS confer cardiovascular risk. Now this has been postulated to be due to enhanced formation of methyl arginines in the kidney that would limit the action of nitric oxide throughout the vasculature. However, the next original paper in this week's journal suggests that this may not be correct. First author, Dr Ricciotti, corresponding author, Dr FitzGerald from University of Pennsylvania Perelman School of Medicine and colleagues, used multiple genetic and pharmacological approaches to disrupt the COX 2 pathway in mice and analyze plasma from patients taking NSAIDS.                                                 However, they did not observe an increase in methyl arginines. In contrast, they did observe an increase in plasma asymmetric dimethylarginine or EDMA in mice-rendered hypertensive by infusion of angiotensin II at a dose that also caused renal impairment. After a four week washout period following the infusion of angiotensin II, blood pressure, creatinine, and ADMA levels all fell back to normal levels.                                                 Celecoxib-treated mice also exhibited increased ADMA and plasma creatinine in response to infusion of angiotensin II and their levels also returned to normal thereafter. Thus, it seems likely that the previous reported elevations in ADMA reflected renal dysfunction rather than a direct consequence of COX 2 deletion or inhibition. The authors end by suggesting that the most plausible mechanism by which NSAIDS confer a cardiovascular risk, is by suppression of COX 2 derived cardioprotective prostaglandins such as Prostacyclin rather than by enhanced formation of methyl arginines.                                                 The next original paper identifies new targets with the potential to prevent vascular malformations in patients with hereditary hemorrhagic telangiectasia. Co-corresponding authors, Dr Ola and Eichmann from Yale University School of Medicine and colleagues looked at SMAD4, which is a downstream effector of transforming growth factor-beta/bone morphogenetic protein family ligands that signal via activin-like kinase receptors.                                                 The authors generated a tamoxifen inducible postnatal endo-fetal specific SMAD for a mutant mouse and showed that SMAD4 prevented flow-induced arterial venous malformations by inhibiting casein kinase II. The uncovered pathways provided novel targets for the treatment of vascular lesions in hereditary hemorrhagic telangiectasia related juvenile polyposis patients carrying SMAD4 mutations.                                                 The next original paper provides important data for the accurate diagnosis of long QT syndrome. Long QT syndrome can be a challenging diagnosis partly because the optimal method for QT assessment is not unequivocally established. QT experts advocate manual measurements with a tangent or threshold method.                                                 In today's paper, first and corresponding author, Dr Vink from Academic Medical Center University of Amsterdam and colleagues, aimed to assess similarities and differences between these two methods of QT interval analysis among 1,484 patients with a confirmed pathogenic variant in either KCNQ1, KCNH2 or SNC5A genes from 265 families. Both QT measurement methods yielded a high inter and intra reader validity and a high diagnostic accuracy.                                                 Using the same current guideline cutoff of QTC interval 480 milliseconds, both methods had similar specificity but yielded a different sensitivity. QTC interval cutoff values for the QT measured by the tangent method was lower compared to that measured by the threshold method. Plus, values were different depending on the correction for heart rate, age, and sex.                                                 The authors provided an adjusted cutoff values specified for method, correction formula, age, and sex. In addition, a freely accessible online probability calculator for long QT syndrome at www.QTcalculator.org has been made available as an aid in the interpretation of the QT interval.                                                 The next original paper demonstrates for the first time that thrombin mediated signaling may play a role in diet-induced atherogenesis. Co-first authors, Dr Raghavan and Singh, corresponding author Dr Rao from University of Tennessee Health Science Center and colleagues, used a mouse model of diet-induced atherosclerosis and molecular biological approaches and explored the role of thrombin and its G protein coupled receptor signaling in diet-induced atherosclerosis.                                                 They found that thrombin-induced CD36 expression and foam cell formation required protease activated receptor 1, G alpha 12, Pyk2, GAB 1, and protein kinase C theta dependent activating transcription factor 2 activation. Thus, inhibition of thrombin G protein coupled receptor signaling could be a promising target for the development of new drugs in reducing the risk of diet-induced atherogenesis.                                                 The next study provides insights into the long- term association of LDL cholesterol with coronary heart disease mortality in individuals at low tenure risks of atherosclerotic cardiovascular disease. First and corresponding author, Dr Abdullah, from VA North Texas Medical Center and UT Southwestern Medical Center and colleagues studied more than 36,000 subjects in the Cooper Clinic Longitudinal Study cohort who are at low tenure estimated risk of atherosclerotic cardiovascular disease. In other words, a low tenure risk of less than 7.5%. They've followed these patients for more than two decades.                                                 Results showed that LDL cholesterol and non-HDL cholesterol at or above 160 milligrams per deciliter were independently associated with a 50 to 80% increased relative risk of cardiovascular disease mortality. The associations between LDL cholesterol and cardiovascular disease mortality were more robust when follow up was extended beyond the traditional 10 year estimated risk period.                                                 The associations remain significant in those with an estimated tenure atherosclerotic cardiovascular disease risk of less than 5%. These data suggests that LDL cholesterol levels at or above 160 milligrams per deciliter in individuals deemed to be at low tenure atherosclerotic cardiovascular risk are associated with worse long term cardiovascular disease mortality. These findings, along with other observational data and data extrapolated from clinical trials, support further consideration of appropriate LDL cholesterol thresholds for lipid lowering interventions in individuals categorized as low short-term risk.                                                 The final paper this week uncovers a novel therapeutic target for the prevention and treatment of thoracic aortic aneurysms. First author, Dr Nogi, corresponding author Dr Shimokawa from Tohoku University Graduate School of Medicine and colleagues, used genetically modified mice to show a pathogenic role of the small GTP binding protein, GDP dissociation stimulator in the development of angiotensin 2 induced thoracic aortic aneurysms and dissection. Down regulation of this protein contributed to dysfunction of aortic smooth muscle cells and hence oxidative stress, and matrix metalloproteinase activities in the pathogenesis of thoracic aortic aneurysms and dissection.                                                 Local over expression of this small GTB binding protein GDP dissociation stimulator around the thoracic aorta inhibited aortic dilatation and rupture in deficient mice. And that wraps it up for this week's summaries. Now for our feature discussion.                                                 Atherosclerosis has been considered a systemic process, meaning that when we see a disease in one vascular bed, we assume that that's a risk marker for disease in other vascular territories, and that they share pathophysiology, they share risk factors. However, if we think about it, the prior studies have all been sort of focusing on coronary and cerebral vascular disease, but today's feature paper changes that a bit because it addresses a key knowledge gap in peripheral artery disease risk, and interestingly suggests that there may be a unique lipid profile that's related to peripheral artery disease.                                                 This is gonna be an exciting discussion and I have the first author, Dr Aaron Aday from Vanderbilt University Medical Center currently. We have our editorialist, Dr Parag Joshi from UT Southwestern, and our associate editor, Dr Anand Rohatgi from UT Southwestern. Welcome gentlemen and Aaron, could we start with you sharing about your study? Dr Aaron Aday:                 So, as you mentioned, a lot of the previous epidemiologic data on atherosclerosis have been primarily in coronary artery disease and stroke, and when we looked at peripheral artery disease or PAD, there seemed to be some subtle differences. So for instance, total cholesterol on HTL cholesterol seemed to be the strongest risk factors for future peripheral artery disease and in terms of LDL cholesterol, the data are somewhat mixed. Some have found a weak association, some have actually found no association. And so building on that, we wanted to see if using nuclear magnetic resonance spectroscopy, we could elucidate more details about the litho protein pathways associated with peripheral artery disease.                                                 And we did this in the women's health study which is a prospective cohort study of women free of cardiovascular disease, the baseline, they were aged 45 and older. And what we've found in terms of the standards with their profiles, we again found that there was no association between LDL cholesterol and future peripheral artery disease, whereas certain standard lipid measures like HDL cholesterol were strongly associated with PAD, and then using the Endemol spectroscopy tool, we found that actually, small LDL particles and total LDL particles were concentrations of both of those markers, were strong risk factors for future PAD and other measures like total HDL particle concentration were even more strongly associated with future PAD than coronary artery disease.                                                 So essentially the signature associated with future peripheral artery disease, had some important differences than that for a composite of coronary artery disease and stroke. Dr Carolyn Lam:                Aaron thanks for that. That's beautifully described and just so intriguing. Parag, could you tell us how should we be thinking about results like this? Dr Parag Joshi:                   It's a great paper and it really highlights a new and unique approach in that we ... Peripheral artery disease as an isolated incident event is fairly understudied I guess we could say and so, this is a really nice paper to start choosing out some of the risk factors for that. I think overall, when we think of peripheral arterial disease in general, I think historically, we've thought of it as similar pathophysiology, you know LDL particles and perhaps other particles depositing in the arterial space. But this does highlight some important differences that might exist and I think one of those seems to be that maybe this is more a signature of elevated remnant lipoproteins or triglyceride rich remnant lipoproteins, small dent LDL particles, low HDL, that sort of metabolic syndrome type patterns that we look at as a high risk factor that may be more contributory to peripheral artery disease than coronary disease, or at least more specific to peripheral artery disease.                                                 I guess one of my main questions about that from your work Aaron is, how can we be sure this isn't just a pre-clinical marker of diabetic patients which we know have this type of pattern? Dr Aaron Aday:                 Sure, it's certainly a possibility. I think what's notable in the cohort, at least a time enrollment. And there was a very little diabetes and actually there was a much greater prevalent of metabolic syndrome. So in my mind, it may be more of a metabolic syndrome specific marker rather than necessarily down the diabetes pathway, but it's certainly something that needs to be explored further. Dr Parag Joshi:                   I wonder whether women's health studies such a healthy cohort that I wonder if this is picking up some signal before the answer to diabetes or as you said, metabolic syndrome, you know which certainly suggests an insulin resistance pattern and we know the association of diabetes with peripheral artery disease is stronger and so I wonder if this may be a sort of earlier way of picking that up. Dr Aaron Aday:                 It may be. I think one thing to notice is the outcome of peripheral artery disease that we're using. So it is symptomatic disease. So, we're not picking up a lot of ulcers that are developing in the future, it's more the claudication and then people who've undergone revascularization. Certainly diabetics have both of those as well but I think that may suggest it's not fully unexplained by developing diabetes than peripheral artery disease further down the line. Dr Parag Joshi:                   Yeah that's a great point. Dr Carolyn Lam:                Yeah great questions, great thoughts. Anand, what about you? Did you have questions too? Dr Anand Rohatgi:            I think from my perspective and thinking about it for circulation and its readership, we found this really interesting for several reasons. Number one, I think is, as you all have discussed, peripheral arterial disease just is not as well characterized and you can see that here in over 25,000 people, add about a 100 a bed, so I think in younger folk, it takes a lot of people to study, to be able to really understand kind of the pathophysiology of peripheral arterial disease.                                                 The other thing that they think they really shed some light on is how this is happening in women in particular and in women, of course as we know have been understudied in all cardiovascular diseases, but in particular, diseases like this which are less common. It's really insightful to see that these lipid abnormalities in women are contributing to peripheral arterial disease more so than your typical LDL cholesterol management and interestingly enough, most of the women who had PAD events in this study, did not have other cardiovascular events.                                                 They really just had PAD events exclusively and I thought that was really intriguing, and the use of this advanced lipoprotein testing, this NMR modality has been very useful in terms of biology and research, and I think that's the case here where we really go under the hood Carolyn, as you said, and get kind of deep dive, the lipid metalobles on abnormalities. And I think Parag and Aaron hit the nail in the head that this is really capturing an insulin resistance of phenotype and what I really liked about this is, instead of studying people who are 70, 80 years old and a lot of things are sort of clustering, a lot of diseases are clustering and they're manifesting all at the same time, it's very hard to tease apart the effective age.                                                 Here, we captured women in their 50s and middle aged, just as they have kind of gone through menopause and this adverse metabolite's phenotype starts to rise in women. And then we could follow them over time and see what the natural history of that is, and the women who have this phenotype go on to have this devastating consequence, this peripheral arterial disease. One of the questions I had then, Aaron for you is, what do you think the implications are from these findings? Does it mean that in terms of diagnostics, we should be doing more advanced testings looking at LDL and HDL type particles with NMR or some other mortality? Does it change therapies with new therapies beings studies right now? What do you think the implications are from your work? Dr Aaron Aday:                 That's important right. I think you mentioned this and I see the inter marked tool in this study, is really a way to try to dig further into the biology of peripheral artery disease as a form of atherosclerosis. I think that we already know patients who are extremely high risk or PAD, those are patients with diabetes, smoking history, metabolic syndrome et cetera., and as you can see in a patient population in 28,000 middle aged women who are pretty healthy, we only had just over a 100 PAD events.                                                 So, I think even if you were to scale this up in terms of cost, I'm not sure that that would necessarily be a viable option for patients, but I think it does suggest that truly focusing on LDL in a very high-risk patient population, meaning patients with PAD, or we may not be fully addressing their risk. And so I think this is a need to highlight that important gap, think about other therapeutic options and we'll soon have ongoing trials, triglyceride low in therapy that may be particularly beneficial in this patient population and so that's how I see this being used. Dr Anand Rohatgi:            That makes a lot of sense and particular because in middle aged women like this, your standard risk score algorithms will not really capture that they're at increased risk, even if they smoke, just because they're women and they're younger and so, I think this really is a call to arms to more refined risk assessment in these women. Dr Parag Joshi:                   Aaron, do you think there's actually a difference in the biology in the peripheral arteries compared to the coronary and cerebral vascular beds, or is there data to kind of look at that or maybe histopathological data to look at that? Dr Aaron Aday:                 We know there's a lot of overlaps, so I don't wanna suggest that PAD is not a former atherosclerosis. I think one limitation is that the primary animal model for PAD is the hyperCKemia model. That doesn't fully recapitulate what's happening in a limb with PAD and so I think that has been one limitation in understanding the biology. But I think what we're starting to see in some clinical trials that have come out in the last couple of years or starting to see a somewhat different signal for therapies in patients with PAD so for instance, in 48, we actually saw that there was a greater benefit to LDL lower [inaudible 00:21:00] inhibitors than for coronary disease. We now have the compass trial results, again, more events, higher risk among these patients but for their benefit, add on River Oxodine therapy, we've seen lymph events or lymph signals in the SGLP2 inhibitor trials. So, I think we're starting to get a sense that there may be something else on top of the traditional ascariasis biology that may be a potential target on down the road. Dr Parag Joshi:                   I think it's really a fascinating biological question of how these different territories might actually differ in their pathophysiology. I think it's a really a nice time to look at this. Also I think, Anand and Aaron both mentioned ongoing trials. The omega 3 fatty acid trials I think reduce it, will be soon to be presented and hopefully published in the next month or so. It would be nice to see if they evaluate peripheral events in that group, I'm sure they will. Dr Carolyn Lam:                Indeed, these have been just such great thoughts and discussion. Nothing really much to add there. I suppose I could say something cheeky like for the first time, and I never thought I'd say it on the podcast, I feel kind of bad that there are no men included in this trial but anyway, I just learnt so much from this. I just wanna thank you gentlemen for a great discussion.                                                 Thank you, listeners, for joining us today and don't forget to tune in again next week to Circulation on the Run.

Quinidine Syncope: There and Back Again - A long QT Tale (Oct 2015) by Oregon 1-800-222-1222

What is Long QT syndrome? Dr. Anil Gehi describes this genetic condition, the different types of Long QT, and the treatments.

What is Long QT syndrome? Dr. Anil Gehi describes this genetic condition, the different types of Long QT, and the treatments.

Dr. Paul Wang:           Welcome to the monthly podcast On the Beat for Circulation Arrhythmia and Electrophysiology. I'm Dr Paul Wang, editor-in-chief, with some of the key highlights for this month's issue. We'll also hear from Dr. Suraj Kapa reporting on new research from the latest journal articles in the field.                                                 In our first article, Barry Maron associates report on the long term clinical course of hypertrophic cardiomyopathy patients following ICD therapy for ventricular arrhythmias. They studied a cohort of 486 high-risk hypertrophic cardiomyopathy patients with ICDs from eight international centers. Of these 486 patients over 6.4 years, 94 patients or 19% experienced appropriate ICD interventions, terminating VT or VF. Of the 94 patients receiving appropriate ICD therapy, 87 were asymptomatic or only mildly symptomatic at the time of appropriate ICD interventions. Of these 87 patients, 74 or 85% remained in classes one or two without significant change in clinical status of the subsequent 5.9 years up to 22 years. Among the 94 patients, there was one sudden death in three patients who died from non arrhythmic hypertrophic cardiomyopathy related processes. Post ICD intervention, freedom from hypertrophic cardiomyopathy, mortality was 100% at one year, 97% at five years, and 92% at 10 years, distinctly lower than the risk of ischemic or non ischemic cardiomyopathy in ICD trials.                                                 Hypertrophic cardiomyopathy patients with ICDs interventions reported the heightened anxiety and expectation of future shocks. However, they did not affect general psychological well-being or quality of life. The authors concluded that in hypertrophic cardiomyopathy, unlike ischemic heart disease, prevention of sudden death with ICD therapies unassociated with a significant increase in cardiovascular morbidity and mortality, nor transformation into heart failure deterioration, ICD therapy does not substantially impair overall psychological and physical well-being. In our next article, Abdulla Damluji and associates examined the cost of hospitalizations for cardiac arrest using the US nationwide inpatient sample from 2003 to 2012. Using the log transformation of inflation adjusted costs the authors examined 1,387,396 patients who were hospitalized after cardiac arrest. They had a mean age of 66 years. Inpatient procedures included coronary angiography in 15%, PCI in 7%, intra-aortic balloon pump in 4.4%, therapeutic hypothermia in 1.1%, and mechanical circulatory support in 0.1% of patients.                                                 Notably the rates of therapeutic hypothermia increased from 0 in 2003 to 2.7 in 2012, p less than 0.001. Both hospital charges inflation adjusted costs linear increased over time. In a multi-variant analysis predictors of inflation adjusted costs included large hospitals size, urban teaching hospital, and length of stay. Among co-morbidities, atrial fibrillation or fluid and electrolytes imbalance were the most common associated with cost. The authors found that during the period between 2003 and 2012 post cardiac arrest, hospitalizations had a steady rise and associated healthcare costs likely related to increase length of stay, medical procedures and systems of care.                                                 In our next paper, Peter Huntjens and associates examined intrinsic interventricular dyssynchrony as a predictor of human dynamic response to cardiac resynchronization. The authors use a cardiovascular computational model CircAdapt to characterize the isolated effect of intrinsic interventricular or intraventricular activation on resynchronization therapy response that is the change in LV dP/dt max. The simulated change in LV dP to dt max had a range of 1.3 to 26.5% increased considerably with increasing inter ventricular dyssynchrony. In contrast, the isolated effect of intra ventricular dyssynchrony was limited with the change in the LV dP/dt max range and the left ventricle from 12.3 to 18.3% in the right ventricle from 14 to 15.7%.                                                 Secondly, electrocardiographic imaging derived activation characteristics of 51 CRT candidates were used to create individual models of ventricular activation in CircAdapt. The model predicted change in LV dP/dt max was close to the actual value in left bundle branch block patients with 2.7% difference between measured and simulated when only intrinsic interventricular dyssynchrony was personalized. Among non left bundle branch block patients a change in LV dP/dt max was systematically over predicted by CircAdapt with a 9.2% difference between measured and simulated. Adding intra ventricular activation to the model did not improve the accuracy of response prediction. The authors found that computer revealed intrinsic interventricular dyssynchrony is the dominant component of the electrical substrate driving the response to CRT.                                                 In the next paper Kenji Kuroki and associates examined the use of voltage limit adjustment of substrate mapping and fast Fourier transform analysis of local ventricular bipolar electrograms during sinus rhythm to predict VT isthmuses. They performed these studies and nine post infarction patients who underwent catheter ablation for total of 13 monomorphic ventricular tachycardias. Relatively higher voltage areas on electroanatomical map or defined as high voltage channels, which were further classified as full or partial if the entire or more than 30% of the high voltage channel was detectable. 12 full high voltage channels were identified in seven of nine patients. Relatively higher fast Fourier transform areas were defined as high frequency channels, which were located on seven of 12 full high voltage channels. Five VT isthmuses or 71% were included in the seven full high voltage channels positive in high frequency channel positive sites.                                                 While no VT isthmuses were found in five full high voltage channel positive but high frequency channel negative sites, high frequency channels were identical to 9 out of 16 partial high voltage channels. Eight VT isthmuses or 89% were included in nine partial high voltage channel positive in high frequency channel positive sites, whereas no VTs isthmuses were found in the seven partial high voltage channel positive and high frequency channel negative sites.                                                 All high voltage channel positive in high-frequency channel positive sites predicted VT isthmus with a sensitivity of 100% and specificity of 80%. The authors concluded that based on this small series that combined use of voltage, limited adjustment and fast Fourier transform analysis may be useful method to detect VT isthmuses.                                                 In the next study, John Whitaker and associates examined the use of lesion index, LSI index, a proprietary algorithm combining contact force, radio-frequency application duration, and RF current. Cardiac CT was used to assess atrial tissue thickness. Ablation lines two to three per animal were created in the right atrium in seven mini pigs with point lesions using 25 watts of energy. Two weeks after the ablation, serial sections of targeted atrial tissue or examine histologically to identify gaps and transmural ablation. LSI guidelines had a lower incidence of histological gaps. Four gaps in the 69 catheter moved or 5.8% compared to ablation using LSI plus two millimeter lines in which there is seven gaps in 33 catheter moves or 21.2% and using LSI plus four millimeter lines in which there are 15 gaps in 23 moves or 65.2% p less than 0.0. The change in LSI was calculated retrospectively is a distance between two adjacent lesions above the mean LSI of the two lesions. Changing LSI values of 1.5 or less were associated with no gaps in transmural ablation.                                                 The authors concluded that in this mod of chronic atrial ablation delivery of uninterrupted transmural linear lesions may be facilitated using LSI to guide catheter movement. When change in LSI between adjacent legions is 1.5 millimeters or lower, no gaps in atrial linear lesions should be expected.                                                 In our next paper, Matthew Bennett and associate examined whether their response to antitachycardia pacing in patients with ICD could further discriminate ventricular from super ventricular arrhythmias in patients receiving ATP in the RAFT trial. The RAFT trial randomized 1,798 patients with New York Heart Association class two or three heart failure, left ventricular ejection fraction less than or equal to 30%, in QRS duration 120 millisecond or greater, to an ICD plus or a minus cardiac resynchronization. Beginning with 10,916 ATP attempts for 8,150 tachycardia episodes in 924 patients, the author's excluded tachycardias where ATP terminated the episode or were the specific etiology tachycardia was uncertain. In this study, they analyzed 3,676 ATP attempts delivered to 2,046 tachycardia episodes in 541 patients. The authors found that a shorter difference between the post pacing interval is PPI minus TCL, was more likely to be associated with VT than SVT, mean of 138.1 milliseconds for VT and 277.4 milliseconds for SVT p, less than 0.001. A PPI minus TCL value of less than or equal to 300 milliseconds had a sensitivity in 97.4% and a specificity of 28.3% for VT.                                                 The authors concluded that specifically the PPI minus TCL following antitachycardia pacing may help distinguish ventricular from supraventricular arrhythmias.                                                 In the next study, Shailee Shah and Amr Barakat and associates examined the outcomes after repeat AF ablation. The authors examined 137 patients out of a total of 10,378 patients undergoing Afib ablation who had had initial long-term success defined from recurrent arrhythmias for greater than 36 months off anti-arrhythmic drugs in subsequent underwent repeat ablation for recurrent atrial fibrillation. The median arrhythmia free period that define long-term success was 52 months. In redo-ablations reconnection of at least one of the pulmonary veins was found in 111 or 81% of patients. Additional non PV ablations were performed in 127 or 92.7% of patients. After a mean follow-up of 17 months, 103 patients or 75% were arrhythmia-free, 79 off anti-arrhythmics, and 24 on arrhythmics. The authors found that repeat ablations with re-isolation to the point of veins and modifying the atrial substrate had a good success rate.                                                 In the next article Qiongling Wang and associates hypothesized that genetic inhibition of CaMKII oxidation in a mouse model of Duchenne muscular dystrophy can alleviate abnormal calcium homeostasis thus preventing ventricular arrhythmias. The authors tested whether the selective loss of oxidation of the CaMKII effects ventricular arrhythmias in the mouse model of Duchenne muscular dystrophy. Genetic inhibition of ox-CaM kinase II by knocking replacement of the regulatory domain methionines with valines, which we'll call MMVV, prevented ventricular tachycardia in the mdx mice. Confocal calcium imaging of ventricular myocytes, isolated from the mdx MMVV mice revealed normalization of intra-calcium release events compared to myocytes from the mdx mice. Abnormal action potentials as assessed by optical mapping mdx were also alleviated by genetic inhibition of ox-CaMK II. Knockout of the NADPH oxidase regulatory sub-unit P 47 Fox normalized elevated ox-CaMK II, repaired intracellular calcium hemostasis and rescued inducible ventricular arrhythmias in the mdx mice. The authors concluded that inhibition of ROS or ox-CaMK II protects against pro-arrhythmic intracellular calcium handling, preventing ventricular arrhythmias in a mouse model of Duchenne muscular dystrophy.                                                 In the next article, Kyohei Marume and Teruo Noguchi and associates examined whether the combination of QRS duration of 120 milliseconds or greater in late gadolinium enhancement is a precise prognostic indicator for the primary endpoint of all cause death and a composite of sudden cardiac death or aborted sudden cardiac death in 531 patients with dilated cardiomyopathy. They also analyzed the association between the combination of late gadolinium enhancement and increased QRS duration in these end points among patients with a class one indication for implantable defibrillator. The author's divided study patients in three groups according to late gadolinium enhancement in QRS duration. Two negative indices that is late gadolinium enhancement negative and narrow QRS, one positive index with either late gadolinium enhancement positive or wide QRS or two positive indices late gadolinium positive and wide QRS and followed them for 3.8 years. Multiple variable Cox regression analysis identified to positive indices as significant predictors of all cause death. A hazard ratio of 4.29 p equals 0.026. Among the 317 patients with a class one indication for ICD, the five year event rate of sudden cardiac death or aborted sudden cardiac death was lowest in the two negative indices groups, 1.4%. With propensity score matching cohorts the two negative indices group had a significant lower event rate of sudden cardiac death or aborted sudden cardiac death than to two other groups hazard ratio 0.2, p equals 0.046.                                                 The authors concluded that the combination of late gadolinium enhancement in wide QRS provides additional prognostic stratification compared to late gadolinium enhancement status alone.                                                 In the next study, Matthew Sulkin and associates examined whether a novel local impedance measurement on an ablation catheter identifies catheter tissue coupling and is predictive of lesion formation. The author's first studied explanted hearts, 10 swine, and then in vivo 10 swine, using an investigational electro anatomical mapping system that measures impedance from an ablation catheter with mini electrodes incorporated into the distal electrode. Rhythmia and Intellanav, Boston Scientific.                                                 Explanted tissue was placed in a warmed 37 degree celsius saline bath mounted on a scale, and the local impedance was measured 15 millimeters away from the tissue to five millimeters of catheter tissue compression at multiple catheter angles. Lesions were created for 31 and 50 watts from 5 to 45 seconds for an N of 70. During in vivo valuation of the local impedance measurements of the myocardium 90 and blood pool 30 were guided by intracardiac ultrasound while operators were blinded to the local impedance data. Lesions were created with 31 and 50 watts for 45 seconds in the ventricle with an n of 72. The local impedance of myocardium, which was 119.7 ohms, was significantly greater than in blood pool 67.6 ohms the p of less than 0.01. Models that incorporate local impedance drop to predict lesion size had better performance that models incorporate force time integral r squared of 0.75 versus r squared of 0.54 and generator impedance drop r squared of 0.2 versus r squared of 0.58. Steam pops displayed a significantly higher starting local impedance and a larger change in local impedance compared to successful RF applications, p less than 0.01.                                                 The authors concluded that local impedance recorded for miniature electrodes provides a valuable measure of catheter tissue coupling and the change in local impedance is predictive of lesion formation during RF ablation.                                                 In the next paper, Boaz Avitall and associates found that the rising impedance recorded from a ring electrode placed two millimeters from the cryoballoon signifies ice formation covering the balloon surface and indicates ice expansion. The authors studied 12 canines in a total of 57 pulmonary veins, which were targeted for isolation. Two cryoapplications were delivered per vein with a minimum of 90 and a maximum 180 second duration. Cryoapplications was terminated upon reaching a 500 ohm change from baseline. Animals recovered 38 plus or minus six days post procedure, and the veins were assessed electrically for isolation. Heart tissue was histological examined. Extra cardiac structures were examined for damage. Pulmonary vein isolation was achieved in 100% of veins if the impedance reached 500 ohms in 90 to 180 seconds. When the final impedance was between 200 and 500 ohms within 180 seconds of freeze time, pulmonary vein isolation was achieved in 86.8%. For impedance of less than 200 ohms pulmonary vein isolation was achieved in 14%. No extra cardiac damage was recorded. The authors found that impedance rise of 500 ohms at less than 90 seconds with a freeze time of 90 seconds resulted in 100% pulmonary vein isolation.                                                 In our final papers Sally-Ann Clur and associates examined left ventricular isovolumetric relaxation time as the potential diagnostic marker for fetal Long QT Syndrome. Left ventricular isovolumetric contraction time, ejection time, left ventricular isovolumetric relaxation time, cycle length, and fetal heart rate were measured using pulse doppler wave forms in fetuses. Time intervals were expressed as percentage of cycle length, and the left ventricular myocardium performance index was calculated. Single measurements were stratified and compared between Long QT Syndrome fetuses and controls. Receiver operator curves were reformed for fetal heart rate in normalized left ventricular isovolumetric relaxation time. A linear mixed effect model including multiple measurements was used to analyze fetal heart rate, the left ventricular iso volume metric relaxation time, and the left ventricular myocardial performance index. There were 33 Long QT fetuses in 469 controls. In Long QT fetuses the left ventricular isovolumetric relaxation time was prolonged in all groups, p less than 0.001, as was the left ventricular isovolumetric relaxation time.                                                 The best cutoff to diagnose Long QT syndrome was the normalized left ventricular isovolumetric relaxation time greater than equal to 11.3 at less than or equal to 20 weeks, giving a sensitivity in 92% and a specificity of 70%. Simultaneous analysis of the normalized left ventricular isovolumetric relaxation time and fetal heart rate improved the sensitivity and specificity of Long QT Syndrome, AUC of 0.96. The normalized left ventricular isovolumetric relaxation time, the left ventricular myocardial performance index, and fetal heart rate trends differed significantly between Long QT Syndrome fetuses and controls throughout gestation.                                                 The authors concluded that left ventricular volumetric relaxation time is Prolonged QT fetuses. Findings of a prolonged normalize left ventricular isovolumetric relaxation time, and sinus bradycardia can improve the prenatal detection of fetal Long QT Syndrome.                                                 That's it for this month, but keep listening. Suraj Kapa will be surveying all journals for the latest topics of interest in our field. Remember to download the podcasts On the Beat. Take it away Suraj. Suraj Kapa:                          Thank you, Paul and welcome back to On the Beat were we will be summarizing hard-hitting articles across the entire electrophysiologic literature. Today we'll be starting within the realm of atrial fibrillation where we're review an article within the realm of anticoagulation and stroke prevention. Quon et al. published in last month's issue of JACC cardiac electrophysiology on anticoagulant use and risk of ischemic stroke and bleeding in patients with secondary atrial fibrillation. It is well known that use of anticoagulation in atrial fibrillation can reduce overall thromboembolic outcomes. However, its role in secondary atrial fibrillation is unclear. Thus, the authors sought to evaluate the effects anticoagulant use on stroke and bleeding risk. Amongst those where atrial fibrillation occurred in the setting of acute coronary syndrome, pulmonary disease, or sepsis. Amongst around 2300 patients evaluated retrospectively there was no evidence of a lower incidence of ischemic stroke among those treated with anticoagulants compared to those who are not.                                                 However, anticoagulation was associated with a higher risk of bleeding in those with new onset AF associated with acute pulmonary disease. The authors suggest as a result that there is unclear overall benefit for long-term anticoagulation in patients with presumed secondary atrial fibrillation. The difficulty in assessing this is how to define secondary atrial fibrillation. However, in many studies patients who developed in the setting of acute illness still had a high risk of developing quote unquote clinically significant AF in long-term follow-up. However, this was not necessarily absolute as many patients not necessarily develop AF that could be considered clinically significant. Thus, the clinical question that arises is: how long should we treat a patient with anticoagulation when they have presumed secondary atrial fibrillation. These data seem to suggest that there may be no net overall benefits. In other words, all-comers with secondary atrial fibrillation should not necessarily be forever treated with anti-coagulation. However, this slightly requires clinical trials to evaluate further.                                                 Next we delve into the realm of cardiac mapping and ablation where we view an article by Gaita et al. entitled 'Very long-term outcome following transcatheter ablation of atrial fibrillation. Are results maintained after 10 years of follow-up?', published in Europace last month. While pulmonary vein isolation is a widely accepted approach for treatment of atrial fibrillation, most reported studies review outcomes in terms of freedom of AF over a relatively short time period, generally two to five years. However longer term follow up is inconsistently reported. Gaita et al. sought to review 10 year outcomes amongst 255 patients undergoing ablation in a single center. They noted 52% remainder arrhythmia-free amongst a mixed cohort of both paroxysmal and persistent patients while 10% progressed to permanent atrial fiBrillation. They found that absence of increases in blood pressure, BMI, and fasting glucose was protective against an arrhythmia recurrence.                                                 These findings suggest that in a relatively small cohort of patients limited to a single center that even long-term outcomes after pulmonary vein isolation are generally quite good, exceeding 50%. However, future freedom from atrial fibrillation is heavily tied to control of other risk factors. In other words, if a patient is going to have poor control of diabetes, blood pressure, or gain weight, the benefit of their pulmonary vein isolation over long-term follow-up is likely less. These data thus highlight both the potential long-term benefit of PVI, but also the importance of counseling patients regarding the need for continued management and control of future and existing risk factors.                                                 Staying within the realm of atrial fibrillation we next review an article by Weng et al. entitled 'Genetic Predisposition, Clinical Risk Factor Burden, and Lifetime Risk of Atrial Fibrillation' published in last month's issue of circulation. The probability of detecting atrial fibrillation in patients based on clinical factors and genetic risk is unknown. Weng et al. sought to clarify whether a combination of clinical and polygenic risk scores could be used to predict risk of developing atrial fibrillation over long-term followup in the Framingham Heart Study. Amongst 4,600 individuals, 580 developed incident atrial fibrillation and had an overall lifetime risk of developing atrial fibrillation of 37%. Those are the lowest risk tertile based on clinical risk factor burden and genetic predisposition had a lifetime risk of 22% versus 48% in the highest. Furthermore, a lower clinical risk factor burden was associated with delayed atrial fibrillation onset. In order to identify patients with atrial fibrillation, before negative sequelae such as stroke occur, patient and physician understanding of risk and monitoring needs is necessary. The fact is that it will be great to identify every single patient who has atrial fibrillation before they have a negative sequela of that atrial fibrillation such as ischemic stroke.                                                 However, performing continuous monitoring of all patients with potential negative sequelae of atrial fibrillation is extraordinarily difficult. The reason is it's excessively costly. We cannot monitor the entire population irrespective of whatever the risk factors are. However, if we're able to identify the highest risk cohorts early on before the atrial fibrillation onsets, this may offer opportunities for use of newer cheaper monitors. The work by Weng et al. suggests one such possible approach combines clinical and polygenic risk scores. Actionability of these data, however, remains to be seen and further validation other cohorts is necessary to clarify generalized ability.                                                 The next article we review is published in last month's issue of the Journal of American College of Cardiology by Lopes at al. entitled 'Digoxin and Mortality in Patients With Atrial Fibrillation. Lopes et al. sought to evaluate the impact of the Digoxin on mortality in patients with atrial fibrillation and the association with the Digoxin serum concentration and heart failure status. They value this association in over 17,000 patients. At baseline 32% were receiving Digoxin. Baseline Digoxin use did not associate with risk of death, but even in these patients a serum concentration of greater than 1.2 nanograms per milliliter was associated with a 56% increase in mortality risk. For each .5 nanogram per milliliter increase in oxygen concentration the hazard ratio increased by 19% for overall mortality. This was irrespective of heart failure status. Furthermore, in patients who are newly started in Digoxin over the follow-up period, the risk and death and sudden death was higher. These data suggests a significant risk associated with Digoxin use for management of atrial fibrillation irrespective of heart failure status. Furthermore, serum valleys above 1.2 require close consideration of dose de-escalation. Whether there is any optimal dose, however, from the study is unclear. These data amongst a host of prior data strongly suggest again strategic use of Digoxin  principally for the management of atrial fibrillation.                                                 Moving on within the realm of atrial fibrillation, we review an article published in last month's issue of Circulation Research by Yan et al. entitled Stress Signaling JNK2 Crosstalk with CaMKII Underlies Enhanced Atrial Arrhythmogenesis. In this more acellular based study the mechanism underlying atrial arrhythmogenesis associated with aging was evaluated. Yan et al. sought to figure out whether the stress response JNK in calcium mediated arrhythmias might contribute to atrial arrhythmogenesis in aged transgenic mouse models. They demonstrated significant increased activity of JNK2 and aging atria, those furthermore associated with rhythmic remodeling. This association was mediated through CaMKII and ryanodine receptor channel function, with activation of the former leading to increased calcium leak mediated by the ladder. This in turn related to increase atrial fibrillation likelihood. Identifying novel targets for atrial fibrillation therapy is critical. Given atrial fibrillation is a complex disease process related to a multitude of risk factors it can be assumed that the contribution of any single factor may be mediated through distinct mechanisms.                                                 Aging in particular as well regarded, but considered to be non-modifiable risk factor for atrial fibrillation. Identifying genes or pathways, the immediate aging associated fibrillation, may take the risk of aging as no longer a non-modifiable thing. The finding of the significance of JNK2 and associate downstream effects with AF risks and aging hearts may hold potential in offering unique therapeutic targets.                                                 Finally, within the realm of atrial fibrillation, we're viewing article by Chen et al. in last month's issue of the Journal of the American Heart Association entitled Association of Atrial Fibrillation With Cognitive Decline and Dementia Over 20 Years: The ARIC-NCS Study. Multiple studies have suggested a significant association between atrial fibrillation risk of dementia. However, these studies have limited time follow-up and were often done and predominantly white patients. Thus, the authors sought to use the data from ARIC, the Atherosclerosis Risk in Communities Neurocognitive Study, to assess the risk of cognitive decline associated with atrial fibrillation. Amongst over 12,000 participants, a quarter of whom are black and half of whom are white, they noted 2100 patients developed atrial fibrillation and 1,150 develop dementia over a 20 year follow up period.                                                 There was a significantly greater risk of cognitive decline amongst those who developed atrial fibrillation. In turn incident atrial fibrillation for the follow-up period was associated with a higher risk of dementia even after adjusting for other clinical and cardiovascular risk factors such as incidents that ischemic stroke. These data further strengthened prior evidence of a direct link between atrial fibrillation and risk of cognitive decline and dementia. Understanding this long-term risk raises the need to additionally identify approaches to prevent this occurrence, which in turn is dependent on understanding the underlying mechanisms. The finding that the risk of cognitive decline dementias independent of ischemic stroke events raises concern that either subclinical micro-embolic events or other factors may be playing a role in this risk and in turn raises question as to how best to prevent them. Until better understood, however, the question of whether the association is causal remains to be seen.                                                 Changing gears yet again, we now delve into the realm of ICDs, pacemakers and CRT. Published in last month, issue of Heart Rhythm Tarakji et al. published a paper entitled 'Unrecognized venous injuries after cardiac implantable electronic device transvenous lead extraction.' Overall risk of transvenous lead extraction includes that of potentially fatal venous laceration. The authors sought to evaluate the incidence of venous injury that may be unrecognized based on microscopic study of extracted leads. Amongst 861 leads obtained from 461 patients they noted 80 leads or almost 9%. Amongst 15% of patients showed segments vein on the lead body, most of which were transmural including the tissue layer. However, in terms of clinical significance, only 1% had need for emergent surgical intervention for clinically significant venous laceration. Risk factors for having the entire vein on the lead included age of lead, ICD leads, and the use of the laser sheath.                                                 These findings suggest that there may be a high incidence of subclinical venous injury after lead extraction though rarely resulting clinically apparent sequelae. As would be expected, venous injury, including transmural removal of portions of the vein traversed by the lead, was more common amongst older leads, which generally more often require laser sheets and ICD leads. The question is however, whether this carries any direct clinical implications. One they may be considered is the potential additive risk of an advancing new lead through the same venous channel, particularly in the setting of potential transmural venous injury that already exists.                                                 Next in last month's issue of Heart Rhythm we review an article by Sharma at al. entitled 'Permanent His-bundle pacing as an alternative to biventricular pacing for cardiac resynchronization therapy: A multicenter experience.' The use of resynchronization therapy for treatment of patients with heart failure and wide QRS has been shown to offer morbidity and mortality benefits. However, many patients maybe non-responders, and recent studies on His bundle pacing of suggested potential clinical benefits. His bundle pacing essentially only requires one pacing catheter attached within the region of the His bundle Sharma et al. sought to evaluate the safety and success rates of His bundle pacing for patients who have either failed standard resynchronization therapy or in whom most tried as a primary intervention. They noted His bundle pacing was successful in 90% of patients with reasonable myocardial and His bundle capture thresholds. Patients in both groups exhibits significant narrowing of QRS morphology and improvement in left ventricular ejection fraction from a mean of 30 to 43%. However, a total of seven patients had lead related complications.                                                 These database on a retrospective analysis of two types of patients, those failing standard biventricular therapy, and those on whom his bundle pacing was attempted as a primary modality suggest overall safety and efficacy in a handful of experienced centers. The promise of His bundle pacing is that a may allow for more effective resynchronization than standard approaches. The high rate of success suggests that His bundle pacing maybe both safe and reasonable to pursue. However randomized trials across more centers are needed to fully prove its benefit, particularly as a primary modality of treatments.                                                 Next we review ICDs and chronic kidney disease. In last month's issue of JAMA cardiology by Bansal at al. entitled 'Long-term Outcomes Associated With Implantable Cardioverter Defibrillator in Adults With Chronic Kidney Disease.' While the benefit of ICDs in patients with low EF is widely recognized, modifying factors that may increase risk of death are not as well defined. These include things like advanced age and chronic kidney disease. Bansal et al. sought to evaluate long-term outcomes and ICD therapy in patients with chronic kidney disease. In retrospective study of almost 5,900 ambulatory patients amongst whom 1550 had an ICD, they found no difference in all cause mortality. However, ICD placement was associated with an increased risk of subsequent hospitalization due to heart failure or any cause hospitalization.                                                 In light of recent studies such as DANISH the robust sense of ICD benefit is being questioned. One of the thoughts for the absence of similar benefit to prior studies lies in the improving care of ambulatory heart failure patients. In patients with chronic kidney disease several questions rises to the risk with ICD, including infectious risk in dialysis patients and the concomitant mortality risk with renal dysfunction. The author suggested in retrospective study, no incremental benefit of ICDs in patients with chronic kidney disease and perhaps some element of added risk is related to hospitalization. However, this study has several limitations. It is retrospective and many patients received ICDs may have been perceived to be sicker in some way. Thus care must be taken in interpretation, but consideration of randomized studies to adjudicate benefit are likely necessary.                                                 Finally, within the realm of devices, we reviewed an article by Tayal et al. entitled "Cardiac Resynchronization Therapy in Patients With Heart Failure and Narrow QRS Complexes.' publishing the Journal of American College of Cardiology last month. Several parameters have been stressed to identify benefit of resynchronization therapy in patients with wide QRS include cross correlation analysis with tissue doppler imaging. However, many patients may have evidence in mechanical dyssynchrony even in the absence of an apparent wide QRS thus Tayal et al. sought to evaluate the benefit of resynchronization therapy amongst 807 patients with heart failure and a narrow QRS mean criteria in a randomized study. Of the 807 46% had delayed mechanical activation. Those without delay mechanical activation had underwent we standardization therapy and were associated with worse overall outcomes likely due to new delayed mechanical activation potentially related to CRT pacing. These data support the absence of a role for resynchronization therapy in patients with a narrow QRS. This is expected as resynchronization therapy likely offers the most benefit in patients with mechanical dyssynchrony that results from electrical dyssynchrony.                                                 Since by its very nature resynchronization therapy relies on non physiologic cardiac pacing thus compared to normal cardiac activation the nature of resynchronization pacing is desynchronization. These data support the absence of a role for resynchronization therapy in patients with heart failure and narrow QRS complexes.                                                 Moving on to cellular electrophysiology we review an article by Kozasa et al. published in last month's issue of Journal of Physiology entitled 'HCN4 pacemaker channels attenuate the parasympathetic response and stabilize the spontaneous firing of the sinoatrial node.' Heart rate is controlled by an interplay between sympathetic and parasympathetic components. In turn HCN4 abnormalities have been implicated in congenital sick sinus syndrome. The authors sought to clarify the contribution of HCN4 to sinus node autonomic regulation. They created a novel gain-of-function mouse where the HCN4 activity could be modulating from zero to three times normal. They then evaluated ambulatory heart-rate variability and responsive heart rate to vagus nerve stimulation. They found HCN4 over-expression did not increase heart rate, but attenuated heart-rate variability. It also attenuated bradycardic response to vagus nerve stimulation. Knockdown of HCN4 in turn lead to sinus arrhythmia and enhanced parasympathetic response. These data suggest HCN4 attenuates sinus node response to vagal stimuli thus stabilizing spontaneous firing of the node. The clinical application of this remain to be seen but are maybe important in that they highlight a mechanism for a heretofore poorly understood mechanism for how exactly HCN4 abnormalities may lead to sick sinus syndrome.                                                 Within the realm of ventricular arrhythmias we highlighted a number of articles published this past month. The first article we review was published in last month's issue of JACC clinical electrophysiology, entitled characterization of the electrode atomic substrate and cardiac sarcoidosis: correlation with imaging findings of scarring inflammation published by [inaudible 00:41:40] et al. In patients with cardiac sarcoidosis one of the questions is how to define the electronic atomic substrate, particularly before we entered the electrophysiology laboratory. Both active inflammation and replacement fibrosis maybe be seen in patients. The authors evaluated in 42 patients with cardiac sarcoidosis, the association between an abnormal electrograms and cardiac imaging findings including PET and Computed Tomography, as well as Cardiac MRI. They noted that amongst these 40 patients, a total of 21,000 electrograms were obtained, and a total of 19% of these were classified as abnormal. Most of the abnormalities occurred in the basal paravalvular segments and intraventricular septum. They further noted that many of these abnormalities in terms of electrograms were located outside the low voltage areas, particularly as it relates to fractionation. In about 90% of patients they notice late gadolinium enhancements and they noted abnormal FDG uptakes suggesting active inflammation in about 48%.                                                 However, it should be noted that only 29 of the 42 patients underwent cardiac imaging. Segments with abnormal electrograms tended to have more late gadolinium enhancement evidence scar transmurality, and also they noted that the association of abnormal PET scan did not necessarily occur with abnormal electrograms. Thus, they concluded that in patients with cardiac sarcoidosis and ventricular tachycardia pre-procedural imaging with cardiac MRI could be useful in detecting electroanatomic map abnormalities that may in turn be potential targets for substrate ablation. However, they were more likely associated with more scar transmurality and lower degrees of inflammation on PET scanning. These data are important in that they highlight potential non-invasive means by which to understand where substrate might occur in patients with the cardiac sarcoidosis. It is well recognized that cardiac sarcoidosis is associated with increased risk of ventricular arrhythmias. These risks have increased ventricular arrhythmias, might be targetable with ablation. Newer therapies might even offer non invasive means by which to perform ablation in patients best. Thus if we could identify non based on mechanisms of identifying the substrate, this will be even more critical.                                                 The critical findings of this particular paper lie in noting that most of the abnormalities still is in intra ventricular sePtum in basal segments, and also that it is MRI in late gadolinium enhancement and associates more with the abnormal electrograms. Interestingly, the absence of inflammation correlating with the presence of more abnormal electrograms suggests that it is not so much the act of inflammation as being reflected in the endocardial map, but the existence of scar.                                                 Next, again within JACC clinical electrophysiology we review an article by Porta-Sánchez et al. entitled 'Multicenter Study of Ischemic Ventricular Tachycardia Ablation With Decrement Evoked Potential Mapping With Extra Stimulus.' The authors sought to conduct a multicenter study of decrement evoked potential base functional tech ventricular tachycardia substrate modification to see if such mechanistic and physiologic strategies could result in reduction in VT burden. It is noted that really only a fraction of the myocardium in what we presume to be substrate based on the presence of low voltage areas are actually involved in the initiation and perpetuation of VT. Thus if we can identify the critical areas within the presumed substrate for ablation, this would be even a better way of potentially honing in on our targets. They included 20 consecutive patients with ischemic cardiomyopathy. During substrate mapping fractionated late potentials were targeted and an extra stimulus was provided to determine which display decrements. All patients underwent DEEP focus ablation with elimination being correlated with VT non-inducibility after radio-frequency ablation. Patients were predominantly male, and they noted that the specificity of these decrement evoked potentials to detect the cardiac isthmus for VT was better than that of using late potentials alone. They noted 15 of 20 patients were free of any VT after ablation of these targets over six months of follow-up, and there was a strong reduction in VT burden compared to six months pre ablation.                                                 They concluded that detriment evoked potential based strategies towards ablation for ventricular tachycardia might identify the functional substrate and those areas most critical to ablation. They in turn regarded that by its physiologic nature it offers greater access to folks to ablation therapies.                                                 This publication is important in that it highlights another means by which we can better hone in on the most critical regions for substrate evaluation in patients with ventricular tachycardia. The fact is more extensive ablation is not necessarily better and might result in increased risk of harm if we think about the potential effects of longer ablations or more ablation lesions. Thus if we could identify ways of only targeting those areas that are most critical to the VT circuits, we could perhaps short and ablation procedural time, allow for novel ways of approaching targeted ablation with limited amounts of ablation performed, or perhaps even improve overall VT outcomes by knowing the areas that are most critical to ensure adequate ablation therapy provided. However, we need to understand that this is still a limited number of patients evaluated in a non randomized manner. Thus whether or not more extensive ablation performed might have been better is as of yet unclear                                                 Staying within the realm of ventricular tachycardia we review an article published in last month's issue of Heart Rhythm by Winterfield et al. entitled the 'Impact of ventricular tachycardia ablation on healthcare utilization.' Catheter ablation of atrial tachycardia has been well accepted to reduce recurrent shocks in patients with ICDs. However, this is a potentially costly procedure, and thus effect on overall long-term health care utilization remains to be seen. The authors sought to evaluate in a large scale real world retrospective study the effect of VT ablation on overall medical expenditures in healthcare utilization. A total 523 patients met study inclusion criteria from the market scan database. After VT ablation median annual cardiac rhythm related medical expenditures actually decreased by over $5,000. Moreover the percentage of patients with at least one cardiac rhythm related hospitalization an ER visit decreased from 53 and 41% before ablation respectively, to 28 and 26% after ablation. Similar changes we're seeing in number of all cause hospitalizations and ER visits. During the year before VT ablation interestingly there was an increasing rate of healthcare resource utilization, but a drastic slowing after ablation.                                                 These data suggests that catheter ablation may lead to reduced hospitalization in overall healthcare utilization. The importance of these findings lies in understanding why we do the things we do. We can provide a number of therapies to patients, but we seek two different effects. One is the individual effect of improving their particular health. The second thing is trying to avoid increasing healthcare expenditures on a population level and making sure resources are utilized. If we can reduce recurrent hospitalizations and overall healthcare expenditure in patients by providing a therapy in addition to provide individual benefit, this is the optimal situation. These data suggests that VT ablation might provide such a benefits, that in fact it reduces overall healthcare utilization while improving overall outcomes.                                                 Next and finally within the realm of ventricular arrhythmias, we review more on the basic side the role of Titin cardiomyopathy leads to altered mitochondrial energetics, increased fibrosis and long-term life-threatening arrhythmias, published by Verdonschot et al. in last month's issue of European Heart Journal. It is known now that truncating Titin variants might be the most prevalent genetic cause of dilated cardiomyopathy. Thus, the authors sought to study clinical parameters and long term outcomes related to Titin abnormalities in dilated cardiomyopathy. They reviewed 303 consecutive and extensively phenotype dilated cardiomyopathy patients who underwent cardiac imaging, Holter monitoring, and endomyocardial biopsy and in turn also underwent DNA sequencing of 47 cardiomyopathy associated genes. 13% of these patients had Titin abnormalities. Over long-term followup they noted that these patients had increased ventricular arrhythmias compared to other types of dilated cardiomyopathy, but interestingly, they had similar survival rates. Arrhythmias in those Titin abnormal patients were most prominent in those who were subjected to an additional environmental trigger, including viral infection, cardiac inflammation, other systemic disease or toxic exposure. They also noted the cardiac mass was relatively reduced in titan admirable patients.                                                 They felt that all components of the mitochondrial electron transport chain we're simply up-regulated in Titin abnormal patients during RNA sequencing and interstitial fibrosis was also augmented. As a result, they concluded that Titin variant associated dilated cardiomyopathy was associated with an increased risk of ventricular arrhythmias, and also with more interstitial fibrosis. For a long time we have reviewed all non ischemic cardiomyopathy as essentially equal. However, more recent data has suggested that we can actually hone in on the cause. In turn, if we hone in on the cause, we might be able to understand the effects of specific therapies for ventricular arrhythmias based on that underlying cause. Patchy fibrosis might not be as amenable, for example, to ablation as discreet substrate that we might see in infarct related VT. Understanding the relative benefit in very specific types of myopathies might hold benefit in understanding how to, one, risk stratify these patients, and two, understand what type of therapy, whether pharmacologic or ablative, might result in greatest benefit to the patients.                                                 Changing gears entirely now to the role of genetics, we review multiple articles in various genetic syndromes published this past month. First, we reviewed an article by Providência et al. published in the last month's issue of heart entitled 'Impact of QTc formulae in the prevalence of short corrected QT interval and impact on probability and diagnosis of short QT syndrome.' The authors sought to assess the overall prevalence of short corrected QT intervals and the impact on diagnosis of short QT syndrome using different methods for correcting the QT interval. In this observational study they reviewed the sudden cardiac death screening of risk factors cohorts. They then applied multiple different correction formulae to the ECGs. They noted that the prevalence of individuals with the QTc less than 330 and 320 was extremely low, namely less than .07 and .02% respectively. They were also more frequently identified using the Framingham correction. The different QTc correction formulae could lead to a shift of anywhere from 5 to 10% of individuals in the cohort overall.                                                 They further noted, that based on consensus criteria, instead of 12 individuals diagnosed with short gut syndrome using the Bazett equation, a different number of individuals would have met diagnostic criteria with other formulae, 11 using Fridericia, 9 with Hodges, and 16 using the Framingham equation. Thus, they noted that overall the prevalence of short QT syndrome exceedingly low and an apparently healthy adult population. However, reclassification as meeting criteria might be heavily dependent on which QT correction formula is used. The importance of these findings is that not all QTs are created equal.                                                 Depending on how you compute the QT interval in which formula to use may affect how you actually risk characterize a patient. Unfortunately, these data do not necessarily tell us which is the right formula, but this highlights that it might be relevant to in the future evaluate the role of different formulae and identifying which is the most necessary to classify a patient.                                                 Moving on to an article published in last month's issue of the journal of clinical investigation by Chai et al. we review an article entitled 'Physiological genomics identifies genetic modifiers of Long QT Syndrome type 2 severity.' Congenital Long QT Syndrome is a very well recognized, inherited channelopathy associated life-threatening arrhythmias. LQTS type 2 is specifically caused by mutations in casein to encoding the potassium channel hERG. However, even with the mutation not all patients exhibit the same phenotype. Namely some patients are more at risk of life threatening arrhythmias in spite of having the same mutation as others who do not exhibit the same severity phenotype. The authors sought to evaluate whether specific modifiable factors within the remaining genetic code might be modifying the existing mutation. Thus, they sought to identify contributors to variable expressivity in an LQT 2 family by using induced pluripotent stem cell derived cardiomyocytes and whole exome sequencing in a synergistic manner.                                                 They found that patients with severely effected LQT 2 displayed prolonged action potentials compare to sales from mildly effected first-degree relatives. Furthermore, stem cells derived from patients were different in terms of how much L-type calcium current they exhibited. They noted that whole exome sequencing identified variants of KCNK17 and the GTP-binding protein REM2 in those patients with more severe phenotypes in whom greater L-type calcium current was seen. This suggests that abnormalities or even polymorphisms in other genes might be modifying the risk attributed to by mutations in the primary gene. This showcases the power of combining complimentary physiological and genomic analysis to identify genetic modifiers and potential therapeutic targets of a monogenic disorder. This is extraordinarily critical as we understand on one level that when we sequence a monogenic disorder that there might exist variants of uncertain significance, namely they have not been classified as disease causing, but could be. In turn, we also recognize that mutations in a family might effect different relatives differently. However, why this is has been relatively unclear.                                                 If we can understand and identify those patients who are most at risk of dangerous abnormal rhythms, this will be useful in how much to follow them, and what type of therapy to use in them. The fact that other genes might modify the risk even in the absence of specific mutations, suggests that novel approaches to characterizing the risk might help for the risk modified patients classification in general. Clinical use, however, remains to be seen.                                                 Moving on from long QT, we evaluate 'The Diagnostic Yield of Brugada Syndrome After Sudden Death With Normal Autopsy' noted in last month's issue of the Journal of American College of Cardiology and published by Papadakis et al. It is well known, the negative autopsies are not uncommon in patients, however, families might be wondering how at risk they are. Thus, the authors sought to assess the impact of systematic ajmaline provocation testing using high right precordial leads on the diagnostic yield Brugada syndrome in a large cohort of Sudden Arrhythmic Death syndrome families. Amongst 303 families affected by Sudden Arrhythmic Death Syndrome evaluation was done to determine whether or not there was a genetic inherited channelopathy cause. An inherited cardiac disease was diagnosed in 42% of the families and 22% of relatives Brugada syndrome was the most prevalent diagnosis overall amongst 28% of families. Ajmaline testing was required, however, to unmask the Brugada Syndrome in 97% of diagnosed individuals. Furthermore, they use of high right precordial leads showed a 16% incremental diagnostic yield of ajmaline testing for diagnosing Brugada syndrome.                                                 They further noted that a spontaneous type 1 regard or pattern or a clinically significant rhythmic event developed in 17% of these concealed regardless syndrome patients. The authors concluded the systematic use of ajmaline testing with high right precordial leads increases the yield of Brugada Syndrome testing in Sudden Arrhythmic Death Syndrome families. Furthermore, they noted that assessments should be performed in expert centers or patients could also be counseled appropriately. These findings are important and one of the big questions always becomes how aggressively to test family members of patients or of deceased individuals who experienced sudden arrhythmic death. Many of these patients have negative autopsies, and genetic autopsy might not be possible due to lack of tissue or blood products that can be adequately tested.                                                 The data here suggest that amongst a group of 303 sudden arrhythmic death, families that Brugada Syndrome is by far the most frequent diagnosis. If an inherited cardiac disease was identified. In turn, it is not ECG alone or echo alone that helps identify them, but requires drug provocation testing in addition to different electrode placements. Whether or not this will consistently offer benefit in patients in general or my result in overcalling remains to be seen next within the realm of genetic predisposition.                                                 We view an area where we don't know if there's a genetic predisposition in article published by Tester et al. entitled Cardiac Genetic Predisposition in Sudden Infant Death Syndrome in last month's issue of the journal of american college of cardiology. Sudden Infant Death Syndrome is the leading cause of post-neonatal mortality and genetic heart diseases might underlie some cases of SIDS. Thus the authors sought to determine the spectrum and prevalence of genetic heart disease associated mutations as a potential monogenic basis for Sudden Infant Death Syndrome. They study the largest cohort to date of unrelated SIDS cases, including a total of 419 individuals who underwent whole exome sequencing and targeted analysis for 90 genetic heart disease susceptibility genes. Overall, 12.6% of these cases had at least one potentially informative genetic heart disease associated variants. The yield was higher in those mixed European ancestry than those of European ancestry.                                                 Infants older than four months were more likely to host a potentially informative gene. Furthermore, they noted that only 18 of the 419 SIDS cases hold a [inaudible 01:01:26] or likely pathogenic variant. So in other words, only 4% of cases really had a variant that they could say was distinctly pathogenic or likely pathogenic. Thus, overall, the minority of SIDS cases have potentially informative variant in genetic heart disease susceptibility gene, and these individuals were mostly in the 4 to 12 month age group. Also, only 4% of cases had immediately clinically actionable variance, namely a variant, which is well recognized as pathogenic and where we could actually say that a specific therapy might have had some effect. These findings can have major implications for how best to investigate SIDS cases in families. It might suggest that SIDS cases where the individual was older, nearly 4 to 12 months of age might have a greater yield in terms of identifying variance.                                                 While this might not affect the deceased in fit, it might affect, families are planning on having another child in whom a variant can be identified.                                                 Finally, within the realm of genetics, we review an article published in last month's issue of Science Advances by Huang. et al. entitled 'Mechanisms of KCNQ1 Channel Dysfunction in Long QT Syndrome Involving Voltage Sensor Domain Mutations'. Mutations that induce loss of function of human KCNQ1 underlie the Long QT Syndrome type 1. While hundreds of mutations have been identified the molecular mechanism by which they result in impaired function are not as well understood. The authors sought to investigate impact of 51 specific variants located within the voltage sensor domain and emphasized effect on cell surface expression, protein folding, and structure. For each variant efficiency of trafficking of the plasma membrane, impact of proteasome inhibition, and protein stability were evaluated. They noted that more than half of the loss of function mutations were seen to destabilized structure of the voltage sensor domain, generally accompanied by mistrafficking and degradation by the proteasome.                                                 They also noted that five of the folding defective Long QT Syndrome mutant sites were located in the S0 helix, where they tend to interact with a number of other loss of function mutation sites in other segments of the voltage sensor domain. They suggested these observations reveal a critical role for the S0 helix as a central scaffold to help organize and stabilized KCNQ1 overall. They also note the importance of these findings is that mutation-induced destabilization of membrane proteins may be a more common cause of disease functioning in humans. The importance of these findings lies in better understanding why specific mutations lead to appa

Jane Ferguson:                Hi, everyone. Welcome to Episode Four of Getting Personal: -Omics of the Heart." I'm Jane Ferguson, an assistant professor at Vanderbilt University Medical Center. This month, we have a special feature from early career member, Andrew Landstrom, who went to the Heart Rhythm Scientific Sessions in Chicago earlier this month and talked to some of the scientists who presented their research. So listen on for interviews Andrews conducted with Anneline te Riele, discussing the challenges and opportunities related to incidental findings in genetic testing, with Ernesto Fernandez, describing his research into whole exome sequencing and Long QT syndrome, and with David Tester, discussing novel variance and pathway analysis in Sudden Infant Death Syndrome. Andrew :                           My name is Andrew Landstrom and I am from the Baylor College of Medicine Department of Pediatrics' section on Cardiovascular Disease. I'm here at the 2017 Heart Rhythm Society Scientific Sessions. Anneline, will you tell us a little bit more about yourself, and what brought you to HRS? Anneline:                          Sure. So my name is Anneline Te Riele, I am a physician from The Netherlands. I finished my medical training in 2012 basically, in The Netherlands, and I started doing a PhD on ARVC in a combined project of our Netherlands patient as well as a group at Hopkins. So what brought me to HRS? I think of course the science. There's a lot of very good science. Actually, I think it's the best meeting for my purposes. Andrew :                           Absolutely. So will you just start by telling us a little bit about the spectrum of genetic testing in the clinic and about both the opportunities and the challenges that it brings? Anneline:                          Sure. So what we do in clinic, and I think this is really the challenge that we're facing currently, is we have moved from just testing on gene or one small panel of genes to bigger panels and then to whole exome or even whole genome sequencing. And I think the good part of that is that in certain cases, certain well-selected cases, you'll get a higher change of actually finding that gene that is responsible for disease.                                            On the contrary, it also leads to a lot of incidental findings. So findings that you were not expecting based on the phenotype of the patient and then you need to deal with those abnormalities that you've found and that brings on a lot of challenges as well for the family but also for us as physicians. Do we then need to screen those families, what do we do with this patient, do we treat them with medical therapies or drugs or do we give them ICDs? That kinds of question. So that I think is a virtually important part of what we're currently dealing with in clinical practice. Andrew :                           It does seem to be a very widespread problem. And here in the US of course we have the American College of Medical Genetics guidelines about reporting a variance. How do you think that that plays into the increased genetic uncertainty here in the US at least? Anneline:                          So that's a great questions. In 2013, the ACMG produced a guideline on which genes to report if you find these incidental findings. So 24 of these genes, and that's actually a big number, 24 of these genes are cardiovascular genes and that's mainly because changes in cardiovascular genes may detrimental effects down the line and really cause death or certain morbidities that are really important for the patient so we do need to deal with that.                                            And the problem with the ACMG guidelines and especially the pathogenicity guidelines is that they require two aspects. They basically require first that the variant was seen before in other cardiomyopathies or in this case other patients with disease. And that's really difficult for cardiomyopathy genes because these are large genes, they have a lot of novel or private mutations in there, so it's really hard to fulfill that requirement of having been seen before.                                            And the second thing is that the ACMG guidelines require functional studies as another proof of evidence of pathogenicity and of course, I think we would all like to do that in all of our patients, but it's just not feasible for financial purposes and all that. So that's a problem that we're facing. There are options and solutions but I think we'll talk about that later, but yeah, I think that's a problem that we're facing. Andrew :                           So on the one hand you have the ability to make a diagnostic decision based on a clear finding, but oftentimes the threshold to calling it a clearly pathologic variant is very high and oftentimes it never rises to that so it becomes more genetic uncertainty. Anneline:                          Yeah. I think that's basically right. And of course in an ideal world, we'll have certainty and say this is likely or this is definitely pathogenic, and this is likely or definitely benign, but in the real world, really, I think maybe even 80, 90% of the cases were in that gray zone in between and we need to deal with that. Andrew :                           Yeah, yeah. And you had some great resources that both scientists and clinicians alike can apply to these unknown, uncertain variants that might clarify things at least a little bit, and what are these tools? Anneline:                          So of course, from a traditional perspective, we have always looked at in silico predictive programs, we'll look at segregation data, and I think they're all very important, but they all have limitations, so for example, in silico predictive programs, they likely overcall mutations deleterious and segregation data is nothing more than evidence of pathogenicity of a locus to a disorder, not necessarily that variant, so the new things that are on the horizon, and a thing that could be the future of [inaudible 00:06:04] interpretation is collaborative project so really we should be collaborating, we should not be having our own little islands. The collaboration is the key here.                                            And collaborative efforts in the US have been for example, ClinVar and NHLBI funded effort, as well as ClinGen and ClinGen, or Clinical Genome, is perhaps the, at least it claims to be, the authoritative central resource to go back to that curates variants as being pathogenic yes or no. And I think these databases, ClinVar finally has a database entry, so the variants will be in ClinVar, but ClinGen provides an expert panel of individuals who will curate these variants as being pathogenic yes or no. I think that is a central resource that we should all be aware of. I know these are not the only ones, there are other collaborative efforts out there.                                            I mean, there are ways to connect clinicians, so for example, Match Maker Exchange is a website that you could use to enter your variant and the phenotype of the patient and you submit your own information and then you'll get matches in other databases, but not only your own match shows up. So if, say, two years later, another physician comes up and looks for the same variant, you'll get a pop up, which will actually be very nice for these clinicians to get in touch. So that's, I think, the feature ... future of variant interpretation is collaboration. That's basically my, I think my main important message here. Andrew :                           I think that's absolutely right. I think this has become sort of a big data question that requires many perspectives, and a lot of resources to be able to curate accurately. What are some of the limitations of these tools that you've seen that kind of, you have to keep in mind in terms of trying to determine whether a variant is truly pathologic or not with a patient that you have sitting in front of you? Anneline:                          So that is, I mean, of course, there's many limitations in the things that we currently do because there's so much that we don't know. But for example, to give you an example, ClinVar I think, is one central resource that we should all be aware of and if you go to ClinVar, there is actually data from two years ago, and I'm sure the numbers are high if we would look now, but if we look in ClinVar two years ago, we already saw that of the, say 120,000 variants that were in the database, 21% of these variants were called VUSes but if you look at these variants, 17% of the cases, the labs or the individual submitters of ClinVar didn't agree on the actual classification of that variant.                                            So the limitations that we all should be aware of is that there is not one single solution and you should look for evidence and really research your variants. So look at Popmap, look at what is out there, look the patient of course, look at the clinical phenotype, does it match what you think the gene should be doing or not, or is it completely unrelated? And then of course search these databases but be aware of the fact that there may be errors there.                                            Another thing I want to highlight too is that we typically go to population databases, so Exome Variant Server, ExAC, I think these are very popular databases that we use to look at the frequency of variants in a selected population. But really these databases may have sub-clinical disease patients, so I know ExAC has three NYBPC-3 mutations that are known to cause HCM, so this is something to keep in mind. There's not a gold standard truth if you open these databases, but you should have multiple pieces of information when interpreting your variant. Andrew :                           And that's a good point. I think with a lot of these cardiomyopathies and channelopathies, particularly some of the more frequent ones, when you have a database of 60,000 people, at least a couple of them are going to have disease. Anneline:                          Yeah. I think that is part of the problem. I mean HCM is pretty prevalent, I mean one in 500 individuals likely, I mean these are recent numbers, has the disease. So I think the cutoff of a minor allele frequency of five percent, which is in the ACMG guidelines, I think is way too high for this disease. So this is what the cardiovascular expert panel of ClinGen has done, so they ... This is, ClinGen, as you might know, Clinical Genome, is a one-on-one team of curators that know the framework of ClinGen and then there is disease experts that are very well accustomed with the disease and the genes associated with it. So they provide teams and these teams work together, and the cardiovascular expert group has recently published a modified, or customized, ACMG guidelines on how to deal with the intricacies of the cardiomyopathies and for example, NYH-7 which is the first genotype deposed in ClinGen or in ClinVar finally.                                            So they modify that cutoff, the minor allele frequency of five percent, which is the BA-1 ACMG guideline cutoff, they changed that to 0.1% and I think that's exactly what you were saying, that is important to keep in mind, some of the cardiomyopathies are way more prevalent so you should not consider that if you see it in a population database that you think that it's, then it's normal, it's not necessarily the case because this is a prevalent disease. Andrew :                           Yeah, and particularly when commercial genetic testing companies all can't agree that a variant is bad, and we all can't agree that a healthy variant may or may not be good, there is definitely a lot of genetic uncertainty there. Anneline:                          Exactly, exactly. Andrew :                           Now, whole-exome sequencing certainly has its role clinically, even with that genetic uncertainty that we spoke about, but it has a clear role in genetic discovery as well. Anneline:                          Sure. Andrew :                           And you were part of a very recent paper, and you led a very long list of authors, speaking more about your collaborative approach to genetics research that evaluated a novel substrate for ARVC, is that correct? Anneline:                          Yes. So this is something I'm actually pretty proud of. As you said, it's a collaborative effort, so it literally take a village to do these kind of studies and we're lucky enough to collaborate with a lot of people who are interested in the same topic. So what we did ... and I metnioned to you in the beginning, I come from the ARVC field ... So what we did is we had one ARVC patient that was discovered by whole-exome sequencing to carry an SCN5A variant and we, in and of itself, found that that was very interesting, because SCN5A, as you know, has been associated with Brugada syndrome predominantly but many other cardiomyopathies as well, so DCM, even ACM. There's been a lot of controversy about SCN5A in that matter.                                            So the computational data, the population data, it all pointed to the fact that this variant may be pathogenic, but we weren't really able to connect those dots just yet. So we then collaborated with the group in NYU with Mario Delmar, who did, first of all, functional studies on the sodium channel, but what was nice is that he was able to use his novel method of super-resolution microscopy which is a way in which we can look at the nano-scale structure of the cardiomyocytes, or really the small, small levels of molecules that you see in these cells. And what we did is we found that not only NAV1.5 which is the gene product of SCN5A but also [inaudible 00:13:53] which is an adherence structure molecule, which links the cells together was actually less present in our ARVC patient compared to the control. And this was in the IPS so cardiomyocyte molecule, which we corrected using CRISPR-Cas9 technology so I think at least in current practice, on of the best pieces of evidence that we can get.                                            So I think this shows that our SCN5A variant, I mean, in this case, probably really was pathogenic, but also in a pathophysiological standpoint, explains to us how SCN5A mutations, which are typically thought to be only affecting the sodium channel, can also lead to cardiomyopathy phenotype which has implications beyond the ARVC world, but also in DCM I think this is a nice finding of collaboration that I think ... I hope more people will look into this. Andrew :                           Absolutely I think the trouble with SCN5A is exactly like you were saying, it's been implicated in Long QT, Brugada Syndrome, SIDS, [inaudible 00:14:57], now ARVC, and even nodal disease, like sinus syndrome and things like that. So the ability to show sort of mechanistically, that while you have a change in your sodium channel gating that you also have a change in the way that the cells can connect with each other and form contractile force is, I guess, key to your study. Anneline:                          Yeah, yeah. I think this really, I mean, I'm hoping at least, it was also finally published in a journal that looks more into functional studies, so not necessarily only genetics, and I think we need to work closely not only on the genetic side, but look closely at the pathophysiological standpoint for gene discovery purposes because this will really explain to us why one gene is implicated in one disease, and also it points to possible directions to perhaps stop the disease process and treat these patients, which I think is vital in our clinical practice. Andrew :                           So are SCN5A mutations in ARVC a common finding or are they rare? Anneline:                          So they are pretty rare. I mean, we do find them every now and then and maybe they're modifiers. So what we did to follow up on that one individual, we check 281 ARVD patients who were screened just by regular screening, not by whole-exome but we did a targeted screening of SCN5A and we found five variants in these 281 patients, so that's two percent. I mean, it's still rare, but it is as rare as any other minor gene causing ARVC, but it is a rare feature, so I mean, I think it could be a player. And interestingly, the phenotype didn't change much. It wasn't really different from the ARVC patients without an SCN5A mutation which is reassuring.                                            What we also saw is that the prevalence of mutations in those with desmosomal mutations. So ARVC is, as you know, typically associated with diseases or mutations in the desmosome. It was more often seen in those without a desmosomal mutation. That was almost double as frequent as in those with a desmosomal mutation. So it does give us some direction to the fact that this may be a player out there. I mean of course it's not Plakophilin-2 which is the major player, I think, in ARVC, but I think it may cause a, at least a certain form of cardiomyopathy of arrhythmogenic cardiomyopathy that we need to be aware of. Andrew :                           And how do you think your new discovery of SCN5A being associated with ARVC, how do you think that plays into the bigger discussion we were having about expansive genetic testing and what that may mean for a patient as far as diagnostic utility but also limitations of variant interpretation? Anneline:                          That's a great question. So I think we should be cautious of saying this gene causes only this disease, and I think this is a common feature not only in ARVC but in a lot of cardiomyopathies and even in channelopathies. I think the concept of one gene causes one disease is outdated. We know that multiple genes have multiple effects and this SCN5A, of course the gene product is NAV1.5 which is the major alpha subunit of the sodium channels so it is really not the canonical function of SCN5A or NAV1.5 that causes cardiomyopathy here but it's a non-canonical function so I think we should be aware of the fact that gene products have different functions and that there can be overlap of the cardiomyopathies. So of course I think we should be screwing SCN5A in our ARVC patients and I'm hoping a lot of labs and a lot of physicians are already doing that, but it's really not the only thing that is associated with ARVC. So that's important to keep in mind. Andrew :                           What do you think the next steps are for sort of broadening the implication of your finding? Anneline:                          So what we are doing currently, and is a little bit of a sneak peek, because this data is not really out there yet, but we have, in this cohort, we found these five variants in 281 individuals, and we're currently working on one of these individuals to get another IPSO cardiomyocyte cell line and look into the functional components to that. And interestingly, this variant, that exact variant in that ARVC patient was also found in a Brugada Syndrome patient. So wouldn't it be nice to actually set them side by side and see what the differences are?                                            Of course this is a little bit of a future music, if you know what I'm saying, like this is something that we don't have just yet, but I think what we need to figure out is how epigenetic or environmental factors play into this field and to explain how one gene or one variant, even, can cause opposite functional effects in different phenotypes. Andrew :                           What do you think is needed to help clarify some of the genetic uncertainty you see clinically? Anneline:                          I think a lot of collaboration, a lot of money, quite frankly. I think we need to ... I mean, the functional data is really helping us not only for understanding that single variant, but also for gene discovery, and as I said, for treatment down the line, that is necessary, and I think the variant of uncertain significance, I mean, if we all live on our little islands and only do our little practices, then we're not going to go a lot further. So we need to work together to understand what your patient has in this variant, my patient had in that variant, and this is our phenotype, so we need to connect those dots to be able to make certain conclusions. Andrew :                           Well, I'm all for collaboration, as well as additional money, that's good. Anneline:                          Good. Andrew :                           Well, thank you so much for spending time with us. Anneline:                          Sure. Andrew :                           And again, congratulations on a wonderful presentation. Anneline:                          Thank you very much. Andrew :                           I'm joined by Dr. Ernesto Fernandez from the Baylor College of Medicine to talk about his research project. Ernesto, I'm wondering if we can just start by introducing yourself and what your project is. Ernesto:                            I am a second-year pediatric resident, I'm applying to a cardiology fellowship right now and I'm interested in, obviously, all aspects of pediatric cardiology. We're trying to figure out whether testing for Long QT genes or Long QT syndrome is actually warranted in otherwise healthy individuals. We're trying to see what the yield is on these testings, specifically whole-exome sequencing. Andrew :                           And I think this project really hits on an important point, whereby, because we've been able to interrogate the genome more comprehensively with clinical testing, that we've run into more incidentally identified variants. And these variants can pop up in genes, like the genes responsible for Long QT syndrome. Talk a little bit more about these variants, what the implication is of finding these variants incidentally, and what your project hoped to target as far as the diagnostic value of these variants. Ernesto:                            Yeah. So I guess the answer to your first question is that we are coming up with these marvelous new techniques of analyzing the genome and now we're using whole-exome sequence testing to look up is someone has any exome that's abnormal and this has caused a huge problem whereby we're now finding all these variants that we don't really know what they mean. We call them variants of undetermined significance.                                            Our study is basically premised by the fact that if you have no underlying suspicion for any arrhythmic disease, there's really no need or no indication to be referred for whole-exome sequencing testing, given that the most likely result is a variant that we don't really know what it means. And it's probably going to be benign. Andrew :                           So on the one hand, you have a well-established gene panel that's being used for diagnostic purposes with you index of suspicion being high for Long QT syndrome versus something like a whole-exome gene screen where somebody may not be thinking about Long QT syndrome as a diagnosis and have low pre-test suspicion but then comes back with a variant found in these genes sort of incidentally. Is that sort of the dichotomy you're drawing? Ernesto:                            Yeah. I think the best way of explaining it is through Bay's Theorem whereby if you have someone with a high index of suspicion when you start off to have sudden cardiac death, a family history of an arrhythmic disease, and you get a test for it, such as a gene panel for Long QT syndrome, and they come up with a positive test result, then you're going to say, "Oh. I should probably evaluate this further," whereas if you have someone who has some dysmorphism, they have delay, they might have seizures, but there's no family history of sudden cardiac death, no personal history of syncope, then there's really no need to send off this big gun, the whole-exome sequence, because you're likely to either get a normal variant or you're likely to get a variant that we don't know what to make of. Andrew :                           So I think, Ernesto, that nicely summarizes the clinical question that you had in mind. What was your hypothesis going into the study, and how did you seek to approach that hypothesis, sort of experimentally? Ernesto:                            So we came up with the hypothesis that if you have an incidentally identified variant within the whole-exome sequencing tests without any other clinical suspicion, it's likely to represent a benign finding. We went about by analyzing the data from the Baylor Miraca labs on the whole-exome sequencing data that they achieved, and we looked specifically at individuals who had gotten these tests and found to have a variant of undetermined significance, or had a pathologic variant for either one or all 17 of the genes for Long QT syndrome. We compared them to individuals who had known Long QT syndrome that had undergone genotype testing, and we [inaudible 00:25:21] these individuals from the literature. And we wanted to compare the whole-exome sequencing cohort to individuals who were otherwise healthy and had obtained a whole-exome sequence. So these are patients or individuals from the well-established ExAC database that are believed to be ostensibly healthy individuals. Andrew :                           So if I understand you correctly, you're comparing this unknown cohort, that being the rare variants found in whole-exome sequencing, against a positive control cohort of pathologic cases versus a negative control cohort of healthy individuals derived from the ExAC database to look for whether those west variants are more similar to the cases or the controls. With regards to the west cohort, what was the prevalence of individuals with these incidentally identified variants, how many did you find? Ernesto:                            So we actually found just about 49% of individuals had some variant in Long QT syndrome gene, and noted that about 12% of them had a mutation in the major causes of Long QT syndrome, and just over a third, or 36% had a mutation in the more rare causes of long QT syndrome. Andrew :                           That's a pretty surprising finding. So you're saying that one in two individuals who get whole-exome sequencing sent for whatever reason, have a variant in a Long QT-associated gene? Ernesto:                            That's what the data suggests. Andrew :                           And where did you go from here? Ernesto:                            So from there, we went onto compare the variant frequency between the case's cohort, those individuals with known Long QT syndrome, those individuals in our west cohort from the Baylor Miraca labs, and those individuals from the ExAC database who are otherwise healthy. So we noted that in our west cohort, there was about 13% of individuals who had a positive variant in the Long QT syndrome one through three genes, the major causes of Long QT syndrome. When we compare that to the ostensibly healthy individuals from the ExAC database, it was 12% in that study that had some variant in Long QT syndrome genes that are major causes of Long QT syndrome itself.                                            This was statistically similar, it was indistinguishable. And then when we compared it to the pathologic cases, it was actually about 50% of those cases who had a positive variant in a Long QT syndrome gene one through three. Andrew :                           So there was a relatively low frequency of individuals who had variants in one of the big three Long QT genes in both controls and the west cohort, and was obviously much higher among individuals with a diagnosis of Long QT syndrome. Ernesto:                            Yep. That's exactly what we found. Andrew :                           And where did you go from here? Ernesto:                            And then from there, we had a good idea that there was probably a big difference between cases and west, but we wanted to make sure, gene by gene, that there was no difference between our west cases and the ExAC database, the control cases. So we mapped each variant frequency by gene for the major causes of Long QT syndrome. There was no statistically significant difference between the west and the controls. Andrew :                           So the gene frequencies between the controls and the west were indistinguishable and very much different, both of them, it would seem, to the pathologic cases. Ernesto:                            Correct. Andrew :                           And you then looked at the position of these variants, the actual amino acid residues, correct? Ernesto:                            Yeah. So we looked at, for KCNQ1, KCNH2, and SCM5A, the three major causes of Long QT syndrome, one, two, three respectively, and we mapped out the amino acid positions where there was actually a mutation for each individuals. So the cases, controls, and pathologic cohorts. We determined the percent overlap between the west cohort and the controls and the percent overlap between the west cohort and the cases and noticed that for all three, there is a huge preference for west and control versus west and cases. Andrew :                           So if you're a west variant you're more likely to reside in the residue also occupied by a healthy individual variant as opposed to a pathologic variant? Ernesto:                            Yeah. Exactly. Andrew :                           And so what did you do next? You retrospectively looked at some of the charts of the patients who were seen at Texas Children's Hospital, correct? Ernesto:                            Mm-hmm (affirmative). So then we had 223 total individuals that had an incidentally identified variant within one of the major three genes, the Long QT syndrome genes. We looked at the reasons for their referrals and noticed that the vast majority of individuals were referred for some developmental delay, for some dysmorphism, for a non-cardiac cause, and then it was only about 23% of these individuals that actually had a reason for referral that was cardiac in nature. And less than on percent of individuals were referred for a solely cardiovascular reason. And we concluded that it's unlikely that these individuals were referred for a cardiac reason, as the data suggests, and that as a result, the index of suspicion for an arrhythmia is likely lower in these individuals. Andrew :                           And what did you find when you looked at the charts of those individuals? Ernesto:                            We had EKG data for a good number of them, and we excluded individuals who obviously had no EKG data, and we excluded individuals who had some congenital abnormality and then anyone with any other arrhythmia that would make the QTC interpretation more difficult, such as interventricular conduction defects.                                            We ended up with 62 individuals and 61 of them had a normal QTC, so there was no evidence of QT prolongation at all. There was one individual who was left who had borderline elevated QTC of 460, which was our cutoff for borderline elevation and this individual had actually been seen by pediatric cardiology at Texas Children's Hospital and found to have ... a history of syncope and it was found to be non-cardiogenic in nature. Andrew :                           So matching the variant data which suggested that you had likely found background variation in the west, you found no evidence of Long QT syndrome in these individuals who had variants in Long QT genes. Ernesto:                            That's correct. So, the overall percent was very similar between the healthy individuals and the west individuals. The variant frequencies were almost indistinguishable, and then the variant co-mapping for all, for both the west and the controls, was preferential to the western cases. So that kind of matched what we found in our study, that there was no clinical suspicion or clinical diagnosis of Long QT syndrome in these individuals who had been found incidentally. Andrew :                           Well that sounds to me to be a pretty big finding. Ernesto:                            Yeah. I think it's pretty important to get this information out there. Andrew :                           So what do you think the take home message for your study is? Ernesto:                            I think the take home message is if you don't have a suspicion of Long QT syndrome or of an arrhythmia, there's low likelihood that such a big gun test as the whole-exome sequence is likely going to change your mind. Andrew :                           So Ernesto, what would you advise a cardiologist who maybe gets a patient in clinic with a chief complaint of a VUS in a Long QT associated gene picked up on west, what would you advise based on your study findings? Ernesto:                            They're going to have to determine their own pre-test suspicion. They're going to have to get a good history and physical, probably get a baseline EKG to determine what the QTC intervals are, and if there's really no other clinical suspicion for Long QT syndrome, they're likely to be able to provide reassurance at that point in time. Andrew :                           Ernesto, what do you think the next steps are for this project, and what do you think still needs to be done in the field to reinforce your conclusions? Ernesto:                            I think my study is one of the early studies of this field, so getting more studies like this and other channelopathies, getting not just looking at Long QT one through three but looking at all of them, and in patients who've been evaluated at Texas Children's or any other institution would be helpful. And then moving forward to give more credence to the idea that if you have history that's reassuring and physical exam that's reassuring, then you probably don't need to have further testing. Andrew :                           What do you recommend if your index of suspicion is high for Long QT syndrome, so maybe a QTC in the low 480s, maybe a family history of syncope or seizures, do you think whole-exome sequencing is the way to go? Ernesto:                            Right now, that's probably not the best test, given all these incidental findings that we don't really know what to do with. There's other tests that are more high-tailored for those specific diseases, like Long QT syndrome panel among others, that are probably more likely to give you a positive post-test probability. Andrew :                           So testing for the disease you're suspicious for as opposed to testing indiscriminately? Ernesto:                            Yeah. Andrew :                           So Ernesto, thank you so much for taking the time our of your day to speak with us. Ernesto:                            Thank you, Andrew. Andrew :                           I'm here with David Tester, senior research technologist working with Mike Ackerman at Mayo Clinic, and he just gave a wonderful talk on whole-exome sequencing and next-generation sequencing as an unbiased look to determine underlying causes of Sudden Infant Death Syndrome, or SIDS. So David, I'm wondering if you can introduce yourself and talk a little bit about your project. Dave:                                 Sure. I'm Dave Tester and I'm at the Mayo Clinic, again with Mike Ackerman. Dr. Ackerman and I have been together for about 18 years now, with a real focus on genetics of sudden cardiac death disorders. So this latest study was looking at whole-exome sequencing in a population of SIDS cases in collaboration with Dr. Elijah Behr at St. George's University in London.                                            And really the approach, what we were aiming for is really kind of two-fold. First we were looking to determine what is the yield of ultra-rare variance within genes that have been implicated in cardiovascular disorders? These would be the cardiac channelopathies and some of the cardiomyopathies such as ACM or ARVC, for example.                                            And the second thing that we were wanting to look at was can we use this to search for sort of novel candidate genes for Sudden Infant Death Syndrome susceptibility? And so we took that aim and really the main result was to show that about 14% of our SIDS cases had what we term potentially informative variants. And those are going to be variants that were within sort of the major channelopathy genes that are implicated in Long QT syndrome or CPVT as well as loss of function variants within the 90 ICC genes that we had examined.                                            Using the ACMG guidelines for determining the pathogenicity of variants, about 4.3% of our SIDS cases hosted an ACMG guideline predicated likely pathogenic to pathogenic variant. And most of those variants represent either a frame shift or splice site error variance really in minor cardiomyopathy genes and channelopathy genes. So there's still a lot of work that needs to be done in terms of looking at specifically missense variance within channel genes and that sort of thing, and really kind of functionally characterizing those to determine whether or not they truly are pathogenic or if they should remain variants of uncertain significance. Andrew :                           And so you took a very complex disease like SIDS with probably a number of differens ideologies and found a pretty good percentage have suspicious variants, that 14% or so, and then 4% had variants that were so suspicious they would meet American College of Medical Genetics guidelines for being a possible or likely pathologic variant. Where do you think this study lies in sort of the continuum of identifying the genetic ideology of SIDS, and what do you think these findings sort of add to that overall picture? Dave:                                 Well I think these findings in general really just kind of show the complexity of SIDS. Whether or not SIDS is really truly genetic or not, or perhaps it just, if it's not monogenic, perhaps it's polygenic, and so those are some things that we should be considering and looking at. Now some of those questions might be able to be answer through our whole-exome sequencing data set that we have, and I think those are really going to be kind of the next phases.                                            We can also take and do some pathway analyses of the exome sequencing data, for example, and see our variance kind of lining up on certain pathways that may contribute to certain pathologies that could contribute to SIDS. Andrew :                           And in your study, you had a few genes where the number of variants that were found in SIDS cases were higher than in your controls. Can you speak some more about what those genes may tell you in the context of pathway analysis for SIDS? Dave:                                 Yes. So there was ... There were not genes that came out with sort of a genome-wide significance level. But there were at least 400 genes that had a p-value of 0.05 over representation in SIDS versus our ethnic match controls and 17 of those genes have a p-value of 0.005 and we're really kind of focused on some of those that have a little bit higher p-value for us to assess. A few of those genes may represent biologically plausible candidate genes for SIDS and we were kind of actually going through and considering which ones we'd like to follow up on in terms of function. Some of these genes do play a role in, say, cardiorespiratory system and function of the heart as well as in the brain. Andrew :                           So then given all these findings, and the fact that you may have some candidate genes and candidate pathways that might be interesting to look at further, what are the next steps that you think would help this project move forward, and what do you think the field of Sudden Infant Death Syndrome and Sudden Unexplained Death Syndrome needs to kind of move forward? Dave:                                 Well I think from a genetic standpoint, the study that we just complete was really on a large set of unrelated infants that had died suddenly. We did not have access to parental DNA and so moving forward in terms of the genetics, I think incorporating sort of a trio analysis I think would get at the question of sort of [inaudible 00:42:01] variance for example. The other things, in terms of genetic standpoint is perhaps looking at different genetic mechanisms. Whether these are copy number variance that may be missed by exome sequencing, perhaps some of the SIDS could be due to epigenetic abnormalities or even small chromosomal abnormalities that perhaps may not be detected on certain arrays on there being used. So I think going forward, kind of taking those approaches to look for sort of unique genetic variation. Andrew :                           Well Dave, thank you so much for taking the time to speak with me and congratulations on a great project. Dave:                                 All right, great, thank you. Jane Ferguson:  Thanks to Andrew for highlighting the interesting precision medicine research presented at HRS and thanks to you all for listening. We'll be back with more next month.

Dr. Paul Wang :                 Welcome to the monthly podcast On the Beat for circulation, arrhythmia and electrophysiology. I’m Dr. Paul Wang editor in chief with some of the key highlights from this month’s issue. We’ll also hear from Dr. Suraj Kapa reporting on new research for the latest journal articles in the field.                                                 The first article in this month's issue is by Yoav Michowitz and Associates who examine the morphological ECG characteristics of left posterior fascicular ventricular tachycardia and differentiated from right bundle branch block and left anterior hemiblock aberrancy. 183 ECGs with left posterior fascicular ventricular tachycardia in patients who underwent ablation were identified using a systematic Medline search were examined and compared to 61 ECGs with right bundle branch block in left anterior hemiblock aberrancy with no obvious cardiac pathology by echocardiography.                                                 Using four variables including atypical right bundle branch block like V1 morphology, positive QRS in aVR, V6R greater than S ratio of less than one and QRS less than or equal to 140 ms, a prediction model was developed that predicted posterior fascicular ventricular tachycardia with a sensitivity of 82% and a specificity of 78%. Patients with three out of four positive variables had a high probability of having left posterior fascicular ventricular tachycardia whereas patients with less than or equal to one positive variable always had right bundle branch block plus left anterior hemiblock.                                                 In the next article, Anna Thøgersen and associates describe a case series of 10 patients in whom implantable cardioverter defibrillators failed to treat ventricular tachyarrhythmias. The authors examine whether consensus derive generic rate threshold cutoffs between 185 and 200 beats per minute were employed in this case series. In nine patients, ventricular fibrillation did not satisfy program detection criteria. Five patients died with untreated ventricular fibrillation, four had cardiac arrest requiring external shocks and one was rescued by a delayed ICD shock. Seven of these patients had slowest detection rates that were consistent with generic recommendations but not tested in a peer review trial for their manufacturer’s ICDs.                                                 In the reported cases, manufacturer specific factors interacted with fast detection rates to withhold therapy including strict ventricular fibrillation episode termination rules, enhancements to minimize T-wave over sensing and features that restrict therapy to regularly rhythms in VT zones. Untreated ventricular fibrillation despite recommended programming accounted for 56% of the deaths and 11% of all of deaths. The authors concluded that complex and unanticipated interactions between manufacturer specific features and generic programming can prevent therapy for ventricular fibrillation.                                                 In the next article, Miguel Rodrigo and associates describe from 17 simulations of atrial fibrillation, atrial flutter and focal atrial tachycardia the ability to understand signal processing that can affect identification of reentrant activity using electrograms, body surface potential mapping and electrocardiographic imaging ECGI phase maps. Reentrant activity was identified by singularity point recognition and raw signals and in signals after narrow band pass filtering at the highest dominant frequency.                                                 Reentrant activity was identified without filtering in 60% of unipolar records but filtering was required to increase reentrant activity detection from 1% to 62% in bipolar recordings. The filtering resulted in residual false reentrant activity in about 30% of bipolar recordings. The authors concluded that rotor identification is accurate and sensitive and does not require additional signal processing in measured or noninvasively computed unipolar electrograms while bipolar electrograms and body surface potential mapping do require highest dominant frequency filtering in order to detect rotors at the expense of a decrease specificity.                                                 In the next article, Raymond Yee and associates examine the ability of a new automated antitachycardia pacing algorithm to reduce ICD shocks. The new automated ATP algorithm was based on electrophysiologic first principles and prescribed the ATP sequences in real time using the same settings for all patients. In 144 patients who had dual chamber or CRT ICDs as well as a history of one or more ICD treated VT or VF episodes or a recorded sustained monomorphic ventricular tachycardia episode. Detection was sent to ventricular fibrillation interval detection of 24 out of 32 ventricular tachycardia interval detection of 16 or greater in a fast VT zone of 242 to 320 ms.                                                 There were 1,626 treated episodes in 49 patients over 14.5 month’s follow up. Data logs permitted adjudication of 702 episodes including 669 sustained monomorphic ventricular tachycardia episodes, 20 polymorphic ventricular tachycardia episodes, 10 SVT episodes and three mal sensing episodes. The novel automated antitachycardia pacing algorithm terminated 39 out of 69 episodes or adjusted 59% of the sustained monomorphic ventricular tachycardia events in the fast VT zone, but 509 out of 590 or 85% adjusted in the VT zone and 6 out of 10 in the VF zone. No SVTs were converted to VT or VF and no anomalous ATP behavior was observed. The authors concluded that this new automated ATP algorithm could be used safely in all zones without need for individualized programming.                                                 In the next study Pablo Ávila and associates studied the incidence and clinical predictors of atrial tachycardias in adults in a cohort of 3,311 patients with congenital heart disease. Prospectively followed in a tertiary center for 37,607 person years. The study patients were divided into three categories; 49% simple, 39% moderate and 12% complex congenital heart disease. In this cohort, 153 or 4.6% of patients presented with atrial tachycardia. The atrial tachycardia burden was highest in complex congenital heart disease such as single ventricle 22.8% or D-TGA 22.1%.                                                 The authors found that univentricular physiology, previous intracardiac repair, systemic right ventricle, pulmonary hypertension, pulmonary regurgitation, pulmonary AV valve regurgitation and pulmonary and systemic ventricular dysfunction were independent risk factors for developing atrial tachycardia. At the age of 40 years, atrial tachycardia free survival in patients with zero risk factors was 100%. With one risk factor, it was 94%. With two risk factors was 76% and three or more risk factors was 50%. These authors confirm these findings in a validation cohort.                                                 In the next article, Khidir Dalouk and associates compare clinical outcomes between ICD patients followed up in a telemedicine videoconferencing clinic and a conventional in person clinic. In this retrospective study, the authors compared time to first appropriate ICD therapy, time to first inappropriate ICD therapy, time to first shock and overall survival. The authors studied 287 patients in the telemedicine videoconferencing clinic group and 236 patients in the conventional in person clinic over mean follow-up duration of 4.8 years. The authors found that telemedicine videoconferencing clinic was not inferior to in person follow-up for the pre-specified outcomes.                                                 In the next article, Elisabeth Mouws and associates studied the epicardial breakthrough waves in sinus rhythm possibly giving insight to the arrhythmogenic substrate in atrial fibrillation. In 381 patients with ischemic or valvular heart disease, intraoperative epicardial mapping with intro electro distance of 2 mm was performed of the right atrium, Bachmann’s bundle, the left atrioventricular groove and the pulmonary vein area. Epicardial breakthrough waves were referred to as sinus node breakthrough waves if they were the earliest right atrial activated site. A total of 218 epicardial breakthrough waves and 57 sinus node breakthrough waves were observed in 168 patients or 44%.                                                 Epicardial breakthrough waves mostly occurred at the right atrium and 48% at the left atrioventricular groove and 31% followed by Bachmann’s bundle and 12% and the pulmonary vein area and 9%. Epicardial breakthrough waves occurred most often in ischemic heart disease patients 49% to valvular patient's 17%. Epicardial breakthrough wave electrograms most often consisted of double or fractionated electrograms seen in 63%. Fractionated epicardial breakthrough wave potentials were more often observed at the right atrium or Bachmann's bundle. The authors concluded that epicardial breakthrough waves are present in over a third of patients possibly indicating muscular connections between the endocardium and epicardium that may enhance the occurrence of epicardial breakthrough waves during atrial fibrillation promoting AF persistence.                                                 In the next article, Shouvik Haldar and associates compare horizontal and vertical orientation bipolar electrograms with novel omnipolar peak to peak voltages in sinus rhythm and atrial fibrillation using a high density fixed multi-electrode plaque placed on the epicardial surface of the left atrium in dogs. Bipolar orientation had significant impact on bipolar electrogram voltages obtained either in sinus rhythm or atrial fibrillation. Omnipole Vmax values were 99.9% larger than both horizontal or vertical electrograms in sinus rhythm in larger than horizontal or vertical electrograms in atrial fibrillation.                                                 Further vector analysis of omnipole electrograms showed that omnipolar electrograms can record electronic voltage unaffected by collision and fractionation. The authors concluded that omnipolar electrograms can attract maximal voltages from AF signals which are not influenced by directional factors, collision or fractionation compared to contemporary bipolar techniques.                                                 In our final article for the month, Pauline Quenin and associates examine the efficacy of screening in relatives of subjects who died suddenly. The authors provided clinical screening to 64 families who experienced unexplained sudden cardiac death before age 45 in a prospective multicenter registry. The diagnosis was established in 16 families, 25% including Brugada syndrome, long QT syndromes, dilated cardiomyopathy and hypertrophic cardiomyopathy. The diagnostic yield was mainly dependent on a number of screen relatives with 3.8 screen relatives in the diagnosed family versus 2.0 in the non-diagnosed families rising to 40% with at least three relatives.                                                 It additionally increased from 9% to 41% when both parents were screened. Diagnostic performance was also dependent on the exhaustiveness of the screening. 70% of complete screening versus 25% with incomplete screening with 17 Brugada syndrome and 15 long QT syndrome diagnoses based on pharmacologic tests. The authors concluded that even without autopsy, familial screening after sudden death in young patients is effective greatly increasing the likelihood of diagnosis in families.                                                 That's it for this month but keep listening. Suraj Kapa will be surveying all journals for the latest articles on topics of interest in our field. Remember to download the podcast On the Beat. Take it away Suraj. Suraj Kapa:                          Thank you Paul. It is my pleasure to welcome everybody back to our continued series of On the Beat articles from across the electrophysiology literature especially selected to highlight their potential importance in terms of either current or future practice within the realm of cardiac electrophysiology. Again, my name is Suraj Kapa and it is my pleasure to walk us through a variety of hard-hitting articles.                                                 Today we’ll be starting within the realm of atrial fibrillation specifically as it relates to cardiac mapping and ablation. The first article was by Iwasawa et al entitled Temperature Controlled Radiofrequency Ablation for Pulmonary Vein Isolation in Patients with Atrial Fibrillation published in volume 70 of the Journal of the American College of Cardiology. In this article, Iwasawa and colleagues discuss the role of novel temperature controlled irrigated ablation catheter to attempt to obtain deeper transmural lesions in cardiac tissue, specifically they tested the utility of a diamond embedded tip for rapid cooling accompanying six surface thermocouples to better reflect tissue temperature.                                                 They demonstrated in this first in human series that a temperature controlled irrigated ablation could produce rapid, efficient and durable PV isolation. The importance of this particular article lies in the continued development of novel tools that can achieve pulmonary vein isolation either more safely or more quickly. This was highlighted in the article by Iwasawa et al when they demonstrated that the mean radiofrequency application duration was significantly less by almost a factor of three and those using the novel radiofrequency ablation catheter versus those with older models.                                                 They also noted that there was lower acute dormant pulmonary vein re-conduction rates and patients tend to have more frequent durable isolation when remapped after ablation. While the study group only consisted of 35 patients within the treatment group and 35 patients within the control group, the potential of these novel catheters to achieve aims of both shortening procedure duration as well as improving procedure and success need to be taken in consideration.                                                 The next article is by Dr. Gopinathannair entitled Atrial Tachycardia after Surgical Atrial Fibrillation Ablation Clinical Characteristics, Electrophysiological Mechanisms and Ablation Outcomes from a large multicenter study published in the August 2017 issue of JACC Clinical Electrophysiology. In this article, Dr. Gopinathannair reviews the outcomes of cardiac mapping and ablation targeted atrial tachycardias occurring after surgical atrial fibrillation ablation. They reviewed a large number of patients nearly 137 undergoing catheter ablation for symptomatic postsurgical atrial fibrillation ablation atrial tachyarrhythmias across three high volume institutions in the United States.                                                 They demonstrated that the vast majority had a left atrial origin though up to a third also had a right atrial origin further atrial tachyarrhythmias. The predominant circuits noted were cavotricuspid isthmus but also frequently perimitral roof and left or right pulmonary veins. In addition, most of the patients namely 93% had at least one pulmonary vein reconnection requiring re-isolation. The key point with the article however were the outcomes. They demonstrated that acute termination inducibility could be achieved in as many as 97% of right atrial and 93% of left atrial tachyarrhythmias in the setting of prior surgical ablation.                                                 Furthermore, 12 month followup demonstrated an 80% success rate. Traditionally, surgical atrial fibrillation ablation is seen as a complex procedure with the remapping of arrhythmias requiring a lot more complexity. However, these findings cross a large group of patients suggesting that we can have a high rate of success should propose to individuals that perhaps targeted ablation at these postsurgical atrial tachyarrhythmias should be amenable towards ablation especially at high volume complex ablation centers.                                                 Next will discuss the article by Pathik et al entitled Epicardial-Endocardial Breakthroughs through Stable Macroreentry: Evidence from ultra-high-resolution three-dimensional mapping published in Heart Rhythm in August 2017. In this article, the group of Pathik et al decided to review whether epicardial-endocardial breakthrough could be discerned during stable right atrial macroreentry using high density and high spatial resolution three-dimensional mapping. Twenty-six patients were studied and they noted that up to 14 patients had evidence of epicardial-endocardial breakthrough. Using systematic entrainment confirmation, stable atrial macroreentry with epicardial-endocardial breakthrough was consistently demonstrated.                                                 The principle of epicardial-endocardial breakthrough or dissociation is critically important during cardiac mapping. While widely accepted for ventricular mapping, the tradition because of lack of available tools and atrial mapping has suggested that endocardial only mapping should reveal the entire cardiac circuits. Advances in signal processing as well as cardiac mapping techniques and technologies has allowed for better discernment of potentially deeper manifestations of cardiac tissue involvement in cardiac arrhythmias. As been well recognized that there can be significant epicardial and endocardial dissociation in cases of persistent atrial fibrillation.                                                 The article by Pathik et al is important in that it highlights that such events can manifest themselves even in the setting of relatively organized or stable atrial macroreentry. Part of the reason this becomes so critical is that when we consider endocardial only remapping and rely on these signals alone, we may run into situations where we miss a significant chamber of atrial tissue namely the epicardium, thus the focus of this article and the consideration of it in the clinician's repertoire of cardiac mapping and ablation should lie in an understanding of the fact that the entire story of an electrical circuits may not be told by traditional endocardial mapping alone without consideration for epicardial-endocardial breakthrough.                                                 The next article we will focus on is by Dr. Chun et al regarding the impact of cryoballoon versus radiofrequency ablation for paroxysmal atrial fibrillation on healthcare utilization and costs and economic analysis. This was from the FIRE and ICE Trial published in the Journal of the American Heart Association this past month. In this study they sought to assess payer cost following cryoballoon or radiofrequency catheter ablation for paroxysmal atrial fibrillation. They demonstrated that there are cost savings of as much as $355,000 related to the use of cryoballoon over traditional radiofrequency catheter ablation. This reduction in resource use and payer costs was consistent across three different national healthcare systems.                                                 Furthermore, the reason for the reduced cost was primarily attributable to fewer repeat ablations and a reduction in cardiovascular rehospitalizations with cryoballoon ablation. In this era of cost reduction, it is important to consider the potential implications of use of novel technologies in terms of procedural costs. The ability to identify novel techniques that can actually both reduce costs and either achieve equal or improved outcomes needs to be strongly considered. While the three national healthcare systems reviewed here might not reflect all healthcare systems or all insurance needs, it still brings up an important economic consideration that all novel technology may not necessarily result in increased costs, and utilization must be considered both in the context of the particular system as well as the particular provider.                                                 Changing pace, we’ll move on with an atrial fibrillation to the role of anticoagulation. The first major article recently published is by Pollack et al regarding the use of Idarucizumab for dabigatran Reversal, the full cohort analysis published the New England Journal of Medicine. Idarucizumab is a monoclonal antibody fragments developed to reverse the anticoagulant effect with dabigatran and represents the first reversal agent available for reversal of any of the novel oral anticoagulant drugs. In this study which is both multicenter, prospective and open label, patients were enrolled to undergo treatment with this reversal agents.                                                 A total 503 patients were included and the median maximum percentage reversal dabigatran was 100% which was measured using the diluted thrombin time or the ecarin clotting time. In those with active bleeding, the median time to cessation of bleeding was around 2.5 hours. Furthermore, in a surgical cohorts who underwent reversal in order to accommodate them going to surgery, the time to initiation of an intended procedures was 1.6 hours with periprocedural hemostasis assessed as normal in 93%, mildly abnormal in 5% and moderately abnormal in 1.5%. Thrombotic events occurred in about 6.3% of patients undergoing reversal because of active bleeding and then 7.4% undergoing reversal for surgical accommodation.                                                 Mortality rates were around 18% to 19%. Thus it was demonstrated that in emergency situations Idarucizumab can rapidly, durably and safely reverse the anticoagulant effect of dabigatran. However, it is important to note that there was a signal for thrombotic events and consideration of the risk of rapid reversal of anticoagulation regardless of the type of anticoagulation in combination with the actual need for reversal should be considered in the patient context.                                                 The next article we will review is by Jackevicius et al entitled Early Non-persistence with Dabigatran and Rivaroxaban in Patients with Atrial Fibrillation, published in Heart this past month. In this article, the group reviewed how patients manage being on their novel oral anticoagulants over the course of time after initial diagnosis and prescription. One of the concerns regarding novel oral anticoagulants is given the fact that there is no actual tracking or no actual measurements needed to ensure continued adherence to the drug, whether or not there will be higher rates of nonpersistence with use of these novel oral anticoagulants.                                                 Amongst 15,857 dabigatran users and 10,119 rivaroxaban users, they noted that at six months about a third of patients were nonpersistent with either drug. In those patients who were nonpersistent with use of the drug, the combined endpoint of stroke, TIA and death was significantly higher with hazard ratios of 1.76 in the dabigatran cohort and 1.89 in the rivaroxaban cohort. Furthermore, the risk of stroke or TIA was markedly higher in nonpersistent patients with about a hazard ratio of 3.75 in dabigatran nonpersistence and 6.25 in rivaroxaban nonpersistence.                                                 Given these relatively high rates of nonpersistence in clinical practice and the negative outcomes associated with nonpersistence, this highlights the importance of continued validation of the need for persistence with use of oral anticoagulation in patients prescribed these perceived to be at high risk of stroke associate with atrial fibrillation. In an era of improving drug use or improving drugs that can be used without the need for blood testing, it must also be considered that these drugs may be more easily stopped on the patient's own discretion without any knowledge from a provider as there is no active blood test associated. Thus this further highlights the importance of continued discussion between patients and physicians over the course of therapy and care regarding the need for continuation.                                                 Changing paces. We review the article by Godier et al entitled Predictors of Pre-procedural Concentrations of Direct Oral Anticoagulants a prospective multicenter study published at the European Heart Journal. We all know that one of the major issue with a direct oral anticoagulants is that these patients frequently undergo elective invasive procedures and in this setting the management can be very challenging specifically as it relates to when the direct oral anticoagulants should and can be safely stopped.                                                 In clinical practice, there is wide variability in the timing by which providers inform patients to stop these new oral anticoagulants prior to invasive procedure. In this prospective multicenter study, 422 patients were evaluated with preprocedural DOAC concentrations and routine hemostasis assays performed to determine those patients who achieved a minimal preprocedural concentration based on the timing of their discontinuation of the drug. They ranged the duration of discontinuation of the oral anticoagulant from 1 to 218 hours. They noted after a 49 to 72 hour discontinuation period, 95% of the concentration of the direct oral anticoagulants in patients had levels that were significantly low suggesting safety and proceeding with any sort of invasive procedure.                                                 Thus a 72 hour discontinuation period predicted sufficiently low concentrations of DOACs with 91% specificity. In multivariable analyses, duration of the DOAC discontinuation with creatinine clearances and antiarrhythmics were independent predictors of a minimal preprocedural DOAC concentration, namely better renal function, longer duration of DOAC discontinuation and interestingly the use of antiarrhythmic drugs were all associated with lower DOAC concentrations. The conclusion from this article was a last DOAC intake of three days before a procedure resulted in a minimal preprocedural anticoagulant effect for almost all patients considered.                                                 The exception would be in moderate renal impairment especially in dabigatran treated patients and antiarrhythmics in anti-Xa-treated patients could result in the need for longer DOAC interruption. Thus, the key things here to note are that antiarrhythmics can result in the need for longer DOAC interruption to achieve minimal blood concentrations and that similarly moderate renal impairment especially in dabigatran treated patients may result in the same. Another outcome other studies suggested a lack of association between routine assays such as routine hemostasis assays and DOAC concentrations suggesting that in situations where testing is believed to be needed routine assays should not replace DOAC concentration measurement in decision-making regarding whether or not the DOAC has sufficiently gone down in concentration to safely proceed.                                                 Along these lines, the final article we will review within the realm of anticoagulation is by Brendel et al entitled the Anticoagulant Effect of Heparin during Radiofrequency Ablation in Patients Taking Apixaban or Rivaroxaban published in the Journal of Interventional Cardiac Electrophysiology this past month. One concern regarding the use of the direct oral anticoagulants is the fact that during procedures where heparin is needed, knowledge of how much heparin to give is unclear. This is both in the setting of understanding what the synergistic effect of the simultaneous and continued use of apixaban or rivaroxaban or other direct oral anticoagulants in combination with heparin might be and also what the effect on actual activated coagulation time might be.                                                 As it is felt that be ACT may not necessarily reflect the true anticoagulant activity of drugs. Thus in a prospective study, Brendel et al studied about 90 patients with atrial fibrillation undergoing radiofrequency ablation procedures. During radiofrequency ablation, unfractionated heparin was given to maintain ACT of 250 to 300 ms with blood samples taken before and up 360 minutes after heparin administration. They demonstrated that heparin displayed a lower anti-Xa activity in rivaroxaban treated patients compared to apixaban treated patients.                                                 In contrast, D-dimer and prothrombin fragment F1+2 plasma levels indicated a higher activation of the coagulation cascade in apixaban/heparin combinations than in rivaroxaban/heparin combinations. While there was clear differences in the level of anticoagulant effect, depending on which DOAC was combined with heparin, they had no clinical impact in terms of bleeding or thromboembolic complications from the procedure. This article is significant in that it highlights that there are clear and different biochemical responses based on which DOAC is used in combination with heparin during radiofrequency ablation.                                                 While in the small study, there was no clear effect on clinical impact, precautions should still be considered when monitoring periprocedural hemostasis in DOAC patients to avoid mismanagement especially considering the variability that might occur between DOACs themselves and not just between DOACs and warfarin.                                                 Changing paces to risk stratification and management within atrial fibrillation. We’ll review the article by Labombarda et al entitled Increasing Prevalence of Atrial Fibrillation and Permanent Atrial Arrhythmias in Congenital Heart Disease published in this past month's issue of the Journal the American College of Cardiology. In this article, they sought to assess the types and patterns of atrial arrhythmias, associate factors and age-related trends in a multicenter cohort of patients with adult congenital heart disease. What they demonstrated is that by far the most common presenting arrhythmia was intraatrial reentrant tachycardia in almost two-thirds of patients with the remaining including atrial fibrillation in up to 30% of patients and focal atrial tachycardias in up to 10% of patients.                                                 The association of intraatrial reentrant tachycardia with congenital heart disease was stronger with higher complexities of congenital heart disease. With those with more complex defects having a higher frequency of IART than those with simple effects. Furthermore, as is commonly seen in the general population, the frequency of atrial fibrillation increased with age to eventually suppress IART as the most common arrhythmia in those greater than equal to 50 years of age. The predominant arrhythmia pattern was paroxysmal in almost two-thirds of patients though almost 30% were persistent.                                                 Furthermore, the frequency of permanent atrial arrhythmias increased with age. While it is commonly seen that patients with congenital heart disease were living longer and as a result it is expected that the frequency of arrhythmias in this population will likely increase. The interesting outcome from the study is the high frequency of intraatrial reentrant tachycardia as the presenting atrial arrhythmia in patients with congenital heart disease and also with the predominantly paroxysmal pattern. The finding also that atrial fibrillation increases in prevalence highlights the importance of closely monitoring these patients in order to assess for anticoagulation needs and options for treatment.                                                 Changing gears to cellular electrophysiology. We focus on an article by Qiao et al entitled transient Notch activation induces long-term gene expression changes leading to sick sinus syndrome in mice published in this past month's issue of Circulation Research. Notch signaling programs cardiac conduction during development and in the adult ventricle. It is noted that injury can induce notch reactivation resulting in global transcriptional and epigenetic changes. Thus, the group sought to determine whether notch reactivation may alter atrial ion channel gene expression arrhythmia inducibility.                                                 They demonstrated that notch signaling regulates transcription factor in ion channel gene expression in adult atrial myocardium. With reactivation inducing electrical changes resulting in sinus bradycardia, sinus pauses and a susceptibility atrial arrhythmias, altogether contributing to a phenotype resembling sick sinus syndrome. The importance of these findings lies in the mechanism underlying sick sinus syndrome.                                                 While we search for genetic clues for why patients might develop atrial fibrillation or sick sinus syndrome or sinus bradycardia as they age, the importance of activation of typically quiet signaling patterns in the adult myocardium and their role in arrhythmogenesis is important because it might highlight novel targets for treatment. Understanding how the arrhythmogenic substrate develops and the mechanisms underlying it, may allow for a better understanding of why in certain patients certain drugs may be effective or not or certain invasive therapies may be effective or not.                                                 Next with the realm of electrocardiography, we’ll review the article by Christophersen et al entitled 15 Genetic Loci Associated with Electrocardiographic P-wave published in Circulation Genetics this past month. Similar to the previous article by Dr. Qiao et al, the importance of the article by Christophersen et al lies in the identification of a number of genetic underpinnings for what forms the final electrocardiographic P-wave that is seen.                                                 Six novel genetic loci associated with P-wave duration and six novel loci associated with P-wave terminal force were identified by the group. Both in the case of the transient Notch activation findings as well as in the findings related to a specific genetic loci associated with electrocardiographic P-wave abnormalities might highlight potential genetic targets either with existing drugs not traditionally used for atrial electrophysiology or potentially future drug targets.                                                 Changing gears yet again, we’ll move on to their own sudden death cardiac arrest and specifically to an article published by Fallavollita et al entitled the denervated myocardium is preferentially associate with sudden cardiac arrest in ischemic cardiomyopathy a pilot competing risks analysis of cost specific mortality. Previous studies identify multiple factors associated with total cardiac mortality but we all recognize the ejection fraction has limited value. Thus within this article published in Circulation: Cardiovascular Imaging, the group decided to do a competing risks analysis the National Institutes of Health sponsored prediction of arrhythmic events with positron emission tomography trial.                                                 They demonstrated that sudden cardiac arrest was correlated with greater volumes of denervate myocardium based on defects on positron emission tomography using a norepinephrine analog carbon 11 hydroxy ephedrine. However, they also demonstrated that other factors such as lack of angiotensin inhibition therapy, elevated BNP and large left particular end-diastolic volume were further associated with sudden cardiac arrest.                                                 The importance of potential modifying factors to better attribute cardiac arrest risk and thus the need for defibrillator or other therapies in patients with myopathy needs to continue to be highlighted especially in light of recently published Danish and other studies suggesting that the mortality benefit conferred by ICD is an ischemic and nonischemic populations may not be equivalent in newer studies. The fact that further risk stratification opportunities can exist underlying the pathophysiologic basis for why these patients develop ventricular arrhythmias is critical. While recognized for a few decades now that myocardial denervation may be associated with sudden cardiac arrest risk, this study highlights the continued need for further study to help further clarify these populations.                                                 Moving onto the realm of genetic channelopathies, we review the article by Anderson et al entitled Lidocaine Attenuation Testing: An in vivo Investigation of Putative LQT3-Associated Variants in the SCN5A-encoded sodium channel published in this past month's issue of Heart Rhythm. Long QT syndrome type 3 represents one of the more difficult types of long QT syndrome to adequately diagnose both by genetic testing as well as through traditional means. Approximate 2% of healthy individuals can have rare variance of uncertain significance in the SCN5A channel and thus distinguishing true LQT3 causative mutations for background genetic noise can be quite difficult in this population.                                                 Anderson et al decided to assess the utility of lidocaine attenuation testing in evaluating patients with possible LQT3. They gave a loading dose of 1 mg per kg of intravenous lidocaine followed by continuous infusions of 50 micrograms for 20 minutes. If the corrected QT interval shortened by at least 30 ms, the LAT was defined as positive. They demonstrated that use of this test can help distinguish true LQT3 causative mutations from otherwise noncontributory variance of uncertain significance. Thus in this era of increasing genetic testing where one might identify a variant of uncertain significance in either a family member affected with sudden cardiac arrest or in a patient being evaluated for any sort of uncertain significant variant, the use of lidocaine testing in those variance as they apply to LQT type 3 may offer significant clinical use.                                                 Next we will review the article by Ishibashi et al published in this past month's edition of Heart entitled Arrhythmia Risk and Beta Blocker Therapy in Pregnant Woman with Long QT Syndrome. One of the biggest concerns of patients with long QT syndrome especially woman is pregnancy. The fact is because of the different hormonal states, it is possible that pregnancy may alter arrhythmic risk and the safety of beta blocker therapy given both the potential fetal effects as well as the continued efficacy at the level those seen previously.                                                 Thus Ishibashi et al reviewed 136 pregnancies across 76 long QT pregnant patients. They retrospectively analyzed clinical and electrophysiological characteristics in pregnancy outcomes in both the presence and absence of beta blocker therapy. All of the beta blocker group had prior events while the majority of the nonbeta blocker group had not been diagnosed with pregnancy. Pregnancy was noted to increase heart rate in those not treated with beta blockers, but interestingly, between the two groups there was no significant difference over the course of pregnancy in QT intervals.                                                 In the beta blocker group, only two events occurred and these were relegated to the postpartum period. However, 12 events occurred in the nonbeta blocker group either during pregnancy and half or in the postpartum period and the remaining half. There was no difference in this frequency of spontaneous abortion between the two groups, and furthermore, fetal growth rates and proportion of infants with congenital malformation were similar between the two groups. However, premature delivery and low birth weight infants were more common in those taking beta blockers.                                                 Given the high risk of events and the relative safety of beta blocker therapy in this population of patients with long QT who become pregnant, it was felt that the use of early diagnosis and beta blocker therapy could be critical both the during pregnancy and during the postpartum period. It was also felt the beta blocker therapy may be tolerated for babies in long QT pregnant patients. This highlights that the continued use of beta blockers throughout the pregnancy and consideration of the introduction of beta blockers in those not already on them during pregnancy may be an important consideration.                                                 Finally within the realm of genetic channelopathies, we focus on the article by Roberts et al entitled Loss of Function in KCNE2 Variants: True Monogenic Culprits of Long QT Syndrome or Proarrhythmic Variants Requiring Secondary Provocation published in this past month's issue of Circulation: Arrhythmia Electrophysiology. As we identify more and more genes the baby is associated with long QT syndrome, the understanding of the clinical phenotype associated with that syndrome requires better study. In this particular study, Roberts et al reviewed the role of long QT syndrome type 6 stemming from mutations in the KCNE2 encoded voltage gated channel beta subunits.                                                 They reviewed mutations identified during arrhythmia evaluation from either inherited arrhythmia clinics or the Rochester long QT syndrome registry. They demonstrated that the high allelic frequencies of LQT6 mutations in the Exome aggregation consortium database and the absence of previous documentation of genotype phenotype segregation suggest many KCNE2 variants and potentially all were actually erroneously designated as LQT as causative mutations. Instead, it was felt the KCNE2 variants may actually confer proarrhythmic susceptibility when provoked by additional environmental and/or acquired or genetic factors.                                                 What they are saying is that identifying the KCNE2 variants as the principal culprits may be over calling the role of the KCNE2 variants and instead it might be a combination of effects such as two hit affect the requires further provocation by either outside or additional genetic factors. Furthermore, complex genetic studies were likely needed to better understand how variants and genes that may not have been previously designated as disease causing play a role in the actual disease process, whether as potentiating other factors that might exist that might also otherwise be relatively benign or as unique singular hits that might by themselves result in the clinical phenotype.                                                 Next moving onto the realm of ventricular arrhythmias, we first focus on an article published in this past month's issue of the American Journal of Physiology, Heart and Circulatory Physiology by Howard Quijano et al entitled Spinal Cord Stimulation Reduces Ventricular Arrhythmias during Acute Ischemia by Attenuation of Regional Myocardial Excitability. In this article, they demonstrated in a porcine model ventricular ischemia that spinal cord stimulation decrease sympathetic nerve activation regionally in ischemic myocardium while having no effect on normal myocardium. They demonstrated that the antiarrhythmic effects conferred by spinal cord stimulation were likely secondary to attenuation of some sympathoexcitation locally in ischemic myocardium rather than changes in the global myocardial electrophysiology.                                                 This is important because it highlights the mechanisms by which spinal cord stimulation may confer in antiarrhythmic benefits in both animal and human models. As we search for novel interventions that can be used for the treatment of ventricular arrhythmias, understanding the underlying pathophysiologic mechanisms by which they work is critical. The understanding that the use of spinal cord stimulation is primarily conferred in a regional way primarily in terms of its effect on an ischemic myocardium, further study is also needed in terms of how the effect is seen in nonischemic myopathies where there may be more patchy scar in the same role of denervation, nerve sprouting and hyper innervation may play different roles.                                                 In the next article we choose to focus on is by Berte et al entitled a New Cryo-energy for Ventricular Tachycardia Ablation a Proof of Concept Study published in this past month's edition of Europace. One of the key problems in ventricular tachycardia ablation is the lack of transmural lesion formation. This is an important determinant of arrhythmia recurrence. Thus the group decided to do a proof of concept study to evaluate the safety and efficacy of a new and more powerful cryoablation system for ventricular ablation. They demonstrated that a novel cryoablation system to create large transmural ventricular lesions, whether it delivered by endocardial or epicardial approach. It was felt that this technology can hold potential for both surgical and catheter-based VT ablation in humans.                                                 While primarily studied in sheep models, it nevertheless highlights the importance of novel therapies that might better achieve through and through lesions. There are many different novel products being developed for the hope of achieving transmural lesions partly to target the myocardial circuits and partly to ensure achievement of through and through lesions without leaving residual potential substrate, because of only partial thickness lesions. These include things like needle ablation catheters, the safety of which still has to be fully evaluated, bipolar ablation or the use of technology such as novel cryo-energy approaches. Comparative efficacy of these different approaches however will be critical to determining which one is safest and best in any given clinical situation.                                                 Next we’ll review the article by Venlet et al published this past month's issue of Circulation Arrhythmia and Electrophysiology entitled Unipolar Endocardial Voltage Mapping in the Right Ventricle: Optimal Cutoff Values Correcting for Computed Tomography-derived Epicardial Fat Thickness and their clinical value for substrate delineation. The work by [inaudible 00:53:37] and others highlighted the importance of using unipolar and bipolar voltage cutoffs and helping delineate areas of both endocardial as well as potentially more distal such as epicardial scar during endocardial mapping. It is felt the low endocardial unipolar voltage during bipolar voltage mapping endocardially may indicate epicardial scar.                                                 However, the primary issues, the additional presence of epicardial fat both in the right ventricle and left ventricle and how this epicardial fat may effect normal unipolar voltage cutoffs. Thus, Venlet et al decided to review using computed tomography data the effective epicardial fat on unipolar voltage cutoffs. They demonstrated that endocardial unipolar voltage cutoff of 3.9 millivolts was more accurate than previously reported cutoff values for right ventricular epicardial scar during endocardial mapping.                                                 It was further demonstrated that while epicardial abnormal electrograms may be associated with transmural scar when associated with low endocardial bipolar voltage, the additional use of endocardial unipolar voltage and normal bipolar voltage sites can improve the diagnostic accuracy resulting in identification of all epicardial abnormal electrograms at sites with less than 1 mm of fat. Thus, the unipolar voltage not only assisted in evaluating whether epicardial scar was present, but also in further clarifying epicardial abnormal electrograms in terms of whether or not they truly represented potential transmural scar.                                                 Finally, within the realm of electrogram mapping of ventricular arrhythmias, we focus on the article by Magtibay et al entitled Physiological Assessment of Ventricular Myocardial Voltage using Omnipolar Electrograms published in the Journal of the American Heart Association this past month. Bipolar electrograms are traditionally used to characterize myocardial health. However, dependence on these electrograms may reduce the reliability of voltage assessment along different planes of arrhythmic myocardial substrates.                                                 Thus, newer catheters rely on evolving tools that might allow for different approaches to bipolar mapping. Using omnipolar electrograms, Magtibay et al studied in healthy rabbits, pigs and diseased humans under paced conditions the role of two bipolar electrode orientations both horizontal and vertical. Voltage maps were created for both bipoles and omnipoles, and they noted that electric orientation affected the bipolar voltage map with an average absolute difference between horizontal and vertical of up to 0.25 millivolts in humans. Thus, they demonstrated omnipoles can provide physiologically relevant and consistent voltages along the maximal bipolar direction and provide an advantage over traditionally obtained bipolar electrograms.                                                 When we consider the use of evolving techniques to get an understanding of myocardial health whether for the purpose of cardiac mapping and ablation or even for the purpose of other intervention such as cardiac biopsy, understanding what the voltage abnormalities perceived actually are is critical to understanding what substrate is actually being targeted. However, given directionality issues in terms of assessment of voltage as well as relative orientation of the catheter in understanding the relevance of received voltage, use of novel signal processing and electro designs are important to consider in the light of their effects on substrate mapping compared to traditional techniques.                                                 Changing gears yet again, but nevertheless related to cardiac mapping and ventricular arrhythmias, we focus on article by Yalagudri et al published in this past month's issue of the Journal of Cardiovascular Electrophysiology entitled A Tailored Approach for Management of Ventricular Tachycardia in Cardiac Sarcoidosis. While in a small number of patients, nearly 14 patients, they attempt to develop a methodology for approaching patients with cardiac sarcoidosis for management of their ventricular arrhythmias. Patients with either cardiac myocarditis or cardiac sarcoidosis represent a particularly difficult cohort to treat.                                                 Prior work by Dr. Roderick Tung and others has demonstrated the high-frequency of perceived inflammatory abnormalities based on cardiac FDG PET scanning amongst patients with ventricular arrhythmias. Whether this reflects cardiac sarcoidosis or other hypermetabolic activity is unclear. However, how to take into account the FDG PET abnormalities when deciding whether or not to take a patient for ablation or how to best treat them in light of their primary disease process is critical.                                                 In this study, the group tried to tailor therapy for ventricular tachycardia and cardiac sarcoidosis according to the phase of disease results. Namely based on the degree of inflammation noted on the FDG PET scan. They noted that via their named clinical protocol, that this tailored therapy could result in good clinical outcome and avoid unnecessary immunosuppression in some patients. Whether or not the use of this tailored therapy approach may apply in larger populations remains to be seen.                                                 Finally within the realm of other EP concepts that might apply broadly across the electrophysiology landscape, we focus on two articles. The first is by Kudryashova et al entitled Virtual Cardiac Monolayers for Electrical Wave Propagation in Nature Scientific Reports this past month. It is the complex structure of cardiac tissue that is considered to be one the main determinants of whether a substrate becomes arrhythmogenic or not. Multiple mathematical and computational models have been developed in order to recapitulate this complex cardiac structure. However, there been varying degrees of limitations in these approaches.                                                 Using a joint in silico-in vitro approach, the group carefully characterized the morphology of cardiac tissue and cultures of neonatal rat ventricular cells and then proposed mathematical models to result in tissue morphology that could be recapitulated for virtual studies of cardiac electrophysiology mainly in order to study wave propagation. They demonstrated in their virtual cardiac monolayers, that the simulated waves had the same anisotropy ratios and wave form complexity as those in in vitro experimental models.                                                 Thus, they demonstrated that they could reproduce both the morphological and physiological properties of cardiac tissue in a virtual landscape. These findings are critical to improving the ability to better study the effects of different antiarrhythmic drugs or interventional techniques on overall cardiac electrophysiology. The difficulty in existing techniques using traditional in vitro cultures is the fact that they’re costly and requires sacrifice of animals that adds to the additional cost of routine studies. The ability to recapitulate actual hearts within a virtual landscape to mimic the cardiac electrophysiology and then study it in a more controlled setting that can be reproducible based on the availability of appropriate computing power is important in terms of future studies within the realm of our field.                                                 The final article we will review is by Das and Dutta published in Physical Review E this past month entitled Controlling Three-Dimensional Vortices using Multiple and Moving External Fields. One of the key studies over the course of the last several years has been that of the role of the spiral and scroll waves in not just atrial fibrillation but ventricular fibrillation and other arrhythmias. It is well recognized that the spiral or scroll waves depending on whether one thinks in a two dimensional or three dimensional substrate may have significant contribution to arrhythmogenesis. Whether targeting the spiral or scroll waves actually eliminates arrhythmias remains to be fully elucidated. However, it also remains to be elucidated exactly how one should control the spiral or scroll waves.                                                 The review by Das and Dutta demonstrated that in fact the spiral or scroll waves could actually be physically moved around and controlled using moving external electric fields and thermal gradients. They show that the scroll rings can be made to trace cyclic trajectories on a rotating electric field or that application of thermal gradients in addition to electric field could deflect the motion and change the nature of a trajectory of a spiral or scroll wave. These findings are important in that they might represent non-ablative techniques that can eventually be used to control spiral or scroll waves in cardiac media, and thus result in either their alteration or termination without the need for additional cardiac injury.                                                 One the biggest problems with additional cardiac ablation in cases such as atrial fibrillation is the fact that they often lead to additional regions of scarring that might lead towards further organized atrial arrhythmias. However, the ability to potentially terminate critical sites responsible for arrhythmogenesis in real time without the need for ablation may represent novel interventions or devices in the future.                                                 I appreciate everyone's attention to these key and hard-hitting articles that we have just focus on from this past month of cardiac electrophysiology across the literature. Thanks for listening. Now back to Paul. Dr. Paul Wang :                 Thanks Suraj. You did a terrific job surveying all journals for the latest articles on topics of interest in our field. There is not an easier way to stay in touch with the latest advances. These summaries and a list of all major articles in our field each month could be downloaded from the Circulation: Arrhythmia and Electrophysiology website. We hope that you’ll find the journal to be the go to place for everyone interested in the field. See you next month.

Dr. Wang:            Welcome to the monthly podcast On The Beat for Circulation, Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, editor-in-chief, with some of the key highlights from this month's issue. We'll also hear from Dr. Suraj Kapa, reporting on new research from the latest journal articles in the field.                                 This month's issue of Circulation: Arrhythmia and Electrophysiology has a number of fascinating and important articles. Let's start with the first article by Philip Halbfass and Associates, which describes the use of esophageal endoscopy in patients undergoing atrial fibrillation ablation. Of 1,802 patients undergoing afib ablation, 832 underwent post-procedural esophageal endoscopy. All patients were ablated using a single tip re-circular ablation catheter. Category one lesions described as erythema erosion were seen in 98 out of these 295 patients, while in 52 out of the 295 patients, ulceration was seen. In three of the 832 patients, esophageal perforation occurred, and in two of the 832 patients, atrial-esophageal fistula occurred.                                 Esophageal perforation only occurred in patients with category two lesions with an absolute risk of 9.6%. The authors concluded that post-ablation esophageal endoscopy is able to identify patients with high-risk lesions. One out of 10 patients with post-ablation esophageal ulcers progressed to perforation, while no patients without esophageal ulcers showed evidence of perforating complications.                                 In the next article by Christian Sohns and Associates describes the relationship between atrial fibrosis identified with magnetic resonance imaging and atrial rotor activity identified by noninvasive electrophysiological mapping. Ten patients underwent pulmonary vein isolation for persistent atrial fibrillation. Late gadolinium enhancement using magnetic resonance imaging, which projected onto the anatomy used for noninvasive electrophysiologic mapping.                                 The noninvasive electrophysiologic mapping identified 410 rotors evenly distributed between the left atrium and the right atrium. This study found that there was no statistically significant association between the presence of late gadolinium enhancement and the presence of rotors.                                 In the next article written by Jereon Venlet examines the endocardial unipolar voltage that best identifies abnormal epicardial electrograms. Thirty-three patients underwent endocardial epicardial right ventricular electro-anatomical mapping in ablation of right ventricular scar-related ventricular tachycardia. Eighty-six percent of abnormal epicardial electrograms had corresponding endocardial sites with bipolar electrogram less than 1.5 millivolts.                                 The remaining abnormal epicardial electrograms could be identified by endocardial unipolar voltages of less than 3.7 millivolts. The authors concluded that this use of endocardial unipolar voltage cut off at normal bipolar voltage sites improves the identification of all abnormal epicardial electrograms where there is less than 1 millimeter of fat.                                 The next article by Alan Bulava and Associates examines the outcomes of hybrid epicardial and endocardial radial frequency ablation, a persistent atrial fibrillation. Seventy patients underwent the epicardial thoracoscopic procedure followed by endocardial mapping ablation two to three months later. At the time of catheter ablation, 76% of patients were in sinus rhythm. All four pulmonary veins were found to be isolated in 69% of the patients and the left atrial posterior wall was isolated in 23% of the patients.                                 In the 12 months after the catheter ablation, 77% were arrhythmia-free, off antirrhythmic drugs. The majority of arrhythmia occurrences occur during the first 12 months following catheter ablation. Using previously ineffective antiarrythmics drugs and re-ablation procedures, arrhythmia-free survival increased to 97% during a mean followup of 936 days. Left atrial volume greater than 165 milliliters, the absence of sinus rhythm before catheter ablation and induce-ability of any sustained tachyarrhythmia at the end of catheter ablation predicted atrial fibrillation recurrence.                                 The authors concluded that the majority of patients after epicardial ablation required endocardial catheter ablation to complete the linear ablation or pulmonary vein isolation lesion sets. In the next article, Jason Roberts and Associates studied the clinical phenotype of Type 6 Long QT Syndrome, stemming from mutations in the KCNE2 encoded voltage gated channel beta subunit.                                 The authors examined individuals reported pathogenic KCNE2 mutations collected from inherited arrhythmia clinics in the Rochester LQTS registry as well as previously reported LQT6 cases identified through a med-line database search. Of 44 probands studied, 16 probands had resting QTC intervals and only developed QT prolongation and malignant arrhythmias following exposure to QT prolonging stressors. Ten had other Long QT pathogenic mutations and 10 did not have a Long QT phenotype, with the remaining eight subjects having a Long QT phenotype, but with evidence suggesting that the KCNE2 variant was not the underlying culprit.                                 The authors noted that the collective frequency of KCNE2 variance implicated in Long QT6 syndrome in the exome aggregation consortium database was 1.4%, in comparison with the 0.0005% estimated clinical prevalence of LQT6 syndrome. Thus, the authors concluded that based on clinical phenotype, the high allelic frequencies of LQT6 mutations in the exome consortium database, in absence of prior documentation of genotype phenotype segregation, many KCNE2 variants, and perhaps all have been erroneously designated as long QT syndrome causative mutations.                                 Instead, KCNE2 variants may confer pro-arrhythmic susceptibility when provoked by additional environmental acquired or genetic factors. In the next article, Alexander Quinn and Associates examine how mechanically-induced ectopy may cause ventricular fibrillation, the mechanism of commotio cordis. It is known that the block of stretched sensitive ATP inactivated potassium channels limits ventricular fibrillation occurrence in a porcine model of commotio cordis.                                 In isolated rabbit heart preparations using optical voltage mapping combined with pharmacological block of potassium ATP or stretch activated cation nonselective channels, the authors showed that the mechanical stimulation reliably triggers premature ventricular excitation at the contact site with induce-ability predicted by local tissue indentation. Mechanically-induced premature ventricular excitation induction is decreased by stretch activated cation nonselective channel block.                                 The authors also found that mechanically-induced premature ventricular excitation resulted in ventricular fibrillation only if the mechanical stimulation site overlaps the re-polarization wave edge in hearts where T-waves involve a well-defined re-polarization edge traversing the epicardium. This defines a narrow subject-specific vulnerable window for commotio cordis-induced ventricular fibrillation in both time and space.                                 In the next article Matthias Seidl and Associates examine the gene expression required for development of atrial fibrillation in a transgenic mouse model. Recent studies showed that atrial fibrillation susceptibility is associated with down regularization of target genes of the CREB/CREM family of transcription factors. CREB/CREM refers to cyclic and P-response element binding protein modulator.                                 Short CREM repressor isoforms like CREM-IbΔC-X bind to cyclical A&P responsive elements preventing transcriptional activation. Messenger RNA for CREM-IbΔC-X is up-regulated in atrial biopsies from patients with paroxysmal or chronic atrial fibrillation. The authors examined transgenic mice expressing CREM-IbΔC-X, which spontaneously developed atrial fibrillation proceeding to permanent fibrillation with age.                                 The authors found that the most prominent alterations of the gene program linked to CREM-induced atria modeling were identified in expression of genes related to structure, metabolism, contractility and electrical activity regulation. In the next article by Takumi Yamada and Associates electrophysiologic characteristics of the idiopathic ventricular arrhythmias originating from the parietal band, one of the muscle bands of the right ventricle, were examined.                                  Of 294 consecutive patients with right ventricular origins, 14 patients had ventricular arrhythmia origins in the parietal band. All patients have left bundle block pattern with 12 inferior and two superior axis. All patients had the notch in the middle of the curess in all cases. Seven patients had precordial transition before lead V3 and four patients had a slow curess onset.                                 Far field ventricular electrogram with an early activation was always recorded in His bundle region regardless of the location of the ventricular arrhythmia origin. During the catheter ablation, a mean number of 10.4 radio frequency of applications with a mean duration of 1,099 seconds were delivered. Catheter ablation was successful in 10 patients and ventricular arrhythmias recurred in four with a mean followup of 41 months.                                 In the Advances in Arrhythmia and Electrophysiology section, the Buza and Associates have reviewed cancer treatment-induced arrhythmias. The authors describe ECD advances in arrhythmias associated with individual cancer chemotherapeutic agents. Now here with a review of the highlights from the articles from journals throughout the world in the past month, is Dr. Suraj Kapa. Dr. Kapa:              Hello. Today we're going to be going over several hard hitting articles we have identified that seem to stand out in the electrophysiological literature from the month of July 2017. The first area we will be delving into is that of atrial fibrillation. Specifically related to cardiac mapping and ablation. The first article in this area that we've chosen was published by Samuel et al. in the Journal of Cardiovascular Electrophysiology entitled Catheter Ablation for the Treatment of Atrial Fibrillation Is Associated with a Reduction in Healthcare Resource Utilization.                                 Samuel et al. reviewed data from a large population base cohort in Quebec, Canada including over 1,500 patients undergoing cardiac ablation for atrial fibrillation. They demonstrated that healthcare resource utilization including hospitalizations, emergency room visits and cardioversions were significantly reduced both 12 months as well as 24 months after the next ablation. These findings seem to suggest that catheter ablation has a sustained overall impact on resource utilization amongst patients with atrial fibrillation.                                 While the study was not randomized and was a retrospective evaluation of outcomes, these findings are provocative. Certainly as we wait for the results of the Cabana trial in about one year we hope to see whether or not cardiac ablation carries the weight of potential beneficial impacts both in terms of long-term care as well as long-term outcomes. Of course being a retrospective evaluation, one question that lies with regards to these findings is whether or not the reduction in resource utilization might be a byproduct of improved ambulatory care of these patients or whether it's a byproduct of patients understanding their disease process better, and thus perhaps not seeking emergency room care or hospitalization as frequently.                                 The next publication we'll focus on was published by Anselmino et al. in The International Journal of Cardiology entitled Conduction Recovery Following Catheter Ablation in Patients with Recurrent Atrial Fibrillation and Heart Failure. This publication synergizes with several other publications that have come out in the month of July. Focusing on the publication by Anselmino et al., they reviewed retrospectively patients undergoing redo atrial fibrillation ablation in the setting of underlying heart failure.                                 What they demonstrated was that nearly a third of patients had no pulmonary vein reconnection, but tended to have more persistent forms of atrial fibrillation suggesting more extensive atrial substraights. This study is complimentary to a publication by [inaudible 00:15:23] et al., published in JACC EP. this past month where they evaluated the longterm outcomes of patients who, when presenting for redo atrial fibrillation ablation had persistent pulmonary vein isolation.                                 In that article, they found that nearly 17% of patients presenting for redo ablation had persistent pulmonary vein isolation. Moreover, these patients tended to perform significantly worse in terms of longterm outcomes than those who presented with PV reconnection, with about a 56% freedom from affiliate swipe after we do ablation in the setting of persistent pulmonary vein isolation as opposed to 76% when there was PV reconnection seen.                                 So the question becomes if we see this greater atrial substraight, should we automatically be doing more ablation? Of course as we all know, there have been many studies performed trying to tease out whether additional ablation in patients who might have more significant atrial substraight carries benefits. In this regard, Fink et al. in last month's edition of Circulation, Arrhythmia and Electrophysiology demonstrated that in fact as an index procedure of performing a stepwise concomitant café plus linear ablation on top of pulmonary vein isolation in persistent and long standing persistent atrial fibrillation patients did not necessarily confer an increased likelihood of longterm success over pulmonary vein isolation alone.                                 Thus, the jury continues to still be out as far as what the right strategy is in many of these patients. However, these studies highlight the importance of continued evaluation and understanding of how we can use information about atrial substraight to guide our ablation procedures more successfully. Changing gears, we'll move on the pathophysiology mechanisms of disease within atrial fibrillation.                                 The article we will choose to focus on here was published by Die et al. in The Journal of Cardiovascular Electrophysiology entitled The Effects of Extrinsic Cardiac Nerve Stimulation on Atrial Fibrillation Induce-ability: The Regulatory Role of the Spinal Cord. Over the course of the last several years many investigators have sought to show that modulation of the autonomic nervous system can successfully alter cardiac electrophysiology and provide antiarrythmic benefits.                                 However, when subject to prospective trials such as the recently published Defeat HF Trial, they have not necessarily found clear benefit. Thus, a critical question becomes how we translate our animal models into human treatment. The interesting results from Die et al. lie in the fact that they looked at the effects of spinal cord stimulation and spinal cord block in addition to concomitant stimulation of other centers such as the venous nerve, the stellate ganglion and ganglionated plexi.                                 They demonstrated that spinal cord stimulation enhanced the effects of venial nerve stimulation while attenuating the effects of stimulating the left stellate ganglion or ganglionated plexus. In turn, the combinations of these different levels of stimulation had different effects on affiliate swipe induce-ability, whether significantly increasing or decreasing the potential.                                 The reason this article is important is it highlights the extensive cross linking and synergy that exists within the autonomic nervous system and that attention paid to only a single center of autonomic innovation may not be sufficient for certain paradigms of care. This past month there were also two reviews summarizing the role of the autonomic nervous system and modulation of that nervous system and the treatment of arrhythmias.                                 The first was by Witt et al. and Europace. The other by Schwartz et al. in the International Journal of Cardiology. These articles help the reader understand the extensive crosslinking and cross communication that might occur, that might sometimes defeat our efforts to use a single element of the autonomic nervous system to modulate cardiac arrhythmias. Changing gears yet again, we'll move on to risk stratification and management for atrial fibrillation.                                 Perino et al. in last month's edition of The Journal of the American College of Cardiology published an article entitled Treating Specialty in Outcomes in Newly Diagnosed Atrial Fibrillation from the Treat AF Study. They present data based on a very large cohort of over 180,000 veterans regarding the effect of treating specialty on atrial fibrillation outcome. Interestingly they demonstrated that when a cardiologist was involved in the care of the patient, there was an overall decrease in stroke and mortality.                                 Albeit with a concomitant increase in hospitalization for AF. The stroke reduction seen was also seen to be secondary to better anticoagulation prescription within 90 days of diagnosis when those patients were seen by a cardiologist as compared with a general internist. This earlier prescription anticoagulation however did not mediate the mortality reduction. These data presented by a Perino et al. are provocative in this era of rising healthcare costs.                                 The question is, as atrial fibrillation rates rise, as the general population ages, how quickly and how aggressively we should engage specialty care early on in patient evaluation. The data by Perino et al. suggests that maybe this engagement should occur earlier. Part of the reasons for this might be improved understanding of current evidence regarding treatment of such patients or better systems of care that allow for providers to identify patients who might need alterations and care faster.                                 However, if anything this is hypothesis-generating. Why anticoagulation prescriptions are delayed when patients are not seen by a specialist or why there would be a difference in mortality are important factors to review further. In this past month Hernandez et al. in Stroke published an article discussing the large degree of geographic variation that exists with regards to appropriate anticoagulation prescription in patients with atrial fibrillation.                                 They demonstrated that there's extensive inhomogeneity across the United States in terms of how and in whom anticoagulation gets prescribed. Thus, how much of these outcomes are specialist-driven, geographically-driven or based on elements of access to care or other issues are going to be important features that have to be evaluated.                                 The next article in risk stratification was published by Mostofsky et al. in Heart, entitle Chocolate Intake and Risk of Clinically Apparent Atrial Fibrillation: The Danish Diet, Cancer and Heart Study. In this study they demonstrated in a population of over 55,000 patients that when accounting for as many variables as they could, higher chocolate intake, more than once per month, was associated with a decreased atrial fibrillation risk when compared with those consuming less chocolate than once per month.                                 Of course, they note that despite these attempts to account for multiple confounding variables, residuary confounders cannot be accounted for. The relevance of this article lies in the question of lifestyle choices patients are asked to make when thinking about how to either prevent themselves from having atrial fibrillation or trying to even treat their atrial fibrillation risk.                                 Chocolate has been shown to have multiple potential beneficial effects in multiple areas of cardiology, however, how to counsel patients with data like these becomes very difficult. The questions lies in how chocolate might mediate arrhythmia risk and how it might also modulate other potential risks such as weight gain or other factors.                                 Thus while important to consider this in light of patients often asking what they can and cannot have, it is important to further consider that we don't understand the full story. The other key element to understand is that really when they say that chocolate intake reduces risk of clinically apparent atrial fibrillation they are speaking about moderate chocolate intake and not necessarily having it for three meals a day.                                 Changing gears away from atrial fibrillation, we will next focus on the area of ICDs pacemakers and CRT. Aberi et al. in Nature's Scientific Reports published regarding inductively power wireless pacing via miniature pacemaker and remote stimulation control system. Their approach provides potential novel opportunities beyond currently available both lead-based and leadless pacemakers and improving battery and allowing for further miniaturization of such devices.                                 They noted by creating a very novel inductive power supply they're able to miniaturize the pacing components and also significantly reduce the power requirements. In fact, they suggested that they could create a leadless device that could be as small as being delivered out of the anterior ventricular vein. This is the first report of such an inductively powered miniaturized pacing system with low enough power consumption that may prove viable for ambulatory human use.                                 The desire to create improved pacing and fibrillation systems is further highlighted by an article published by [Kalu 00:25:41] et al. in JACC Clinical Electrophysiology this past month where they demonstrated initial results of percutaneous epicardially delivered partially insulated defibrillator lead. Work like these holds the potential to improve options for patients and in traditional vascular access is not desired, or an identifying new ways of delivering pacing therapy that exists outside the traditional lead base or even somewhat miniaturized leadless approaches.                                 We'll next focus on the area of sudden death and cardiac arrest. The first article we'll focus on was published by Stecker et al. in The Journal of The American Heart Association entitled Health Insurance Expansion and Incidence of Out of Hospital Cardiac Arrest: A Pilot Study in the US Metropolitan Community. This article looked at the results of The Affordable Care Act, mainly health insurance expansion, on the rate of out of hospital cardiac arrest in a large US metropolitan community of over 600,000 people.                                 They separately studied a middle aged population that might have been affected by healthcare expansion versus an older population, above 65, who would have had relatively stable insurance plans having been covered by Medicare both prior to and after this change in healthcare plans. They demonstrated that there was a significant decrease in overall out of hospital cardiac arrests amongst middle age people without any significant change amongst the more elderly Medicare population in the same time period.                                 The time period studied was relatively short, nearly less than a decade. Of course, whether there were other events that might have occurred to alter this risk such as improvements in care beyond the combination of availability and mandates plus carrying health insurance, it remains to be seen. However, the data is very suggestive. Further evaluation at the national level in varying communities however would be useful, as well as consideration of population level cost benefit analysis.                                 The next article published by Shen et al. in the New England Journal of Medicine entitled Declining Risk of Sudden Death in Heart Failure. They presented data across 40,000 patients from multiple clinical trials over two decades regarding the changing rates of sudden death amongst heart failure patients. Interestingly they noted there was an overall 44% reduction in sudden death rates across these trials over time dating from the 1990s to 2014.                                 In the earliest trials considered, the mortality rate within 90 days after randomization was as high as 2.4% while the most recent trials suggest that that rate is more like 1.0%. This profound decline was attributed to improved usage and prescription of medications early on in the heart failure course, which may modulate outcomes.                                 The relevance of these findings lies in trials that have been published recently and met analysis that we've discussed regarding utility of defibrillators in nonischemic cardiomyopathy or even ischemic cardiomyopathy. The recently published Danish study suggested that ICDs might not confer an equivalent mortality risk as what would have been expected years ago. However, this publication by Shen et al. is particularly provocative because it calls into question whether the same mortality benefit we anticipated from earlier heart failure trials should still be the rubric by which current defibrillator trials are powered.                                 Namely, if we consider that Danish saw the 25% difference in mortality, with a 44% overall reduction in sudden death seen in trials over time for heart failure, seeking a 25% reduction might be excessive. Thus, this highlights the need to potentially power trials for ICDs and the benefit of such ICDs better. This importance of better stratifying better heart failure patients for sudden death risk has been raised in multiple articles this month, including in a review by Holiday et al. in Circulation and in the series of reviews published in Volume 237 of The International Journal of Cardiology.                                 The last article we choose to focus on in the role of sudden death and cardiac arrest was published by Vehmeijer in Circulation: Arrhythmia and Electrophysiology entitled Prevention of Sudden Cardiac Death in Adults with Congenital Heart Disease: Do the Guidelines Fall Short? They reviewed outcomes amongst 26,000 adults with congenital heart disease in light of existing guidelines for risk prediction and prevention of sudden death.                                 They demonstrated that less than half of the patients with sudden cardiac death actually had a guideline basis recommendation for an ICD on the basis of either the 2014 consensus statement on arrhythmias or the 2015 European Society of Cardiology Guidelines. These findings are very provocative in suggesting that we don't really understand who requires treatment amongst adults with congenital heart disease.                                 With improved care paradigms, both with improvements in surgical outcomes as well as ambulatory care of these patients and recognition of need for interventions, arrhythmias are becoming a greater and greater problem amongst patients with adult congenital heart disease. However, large scale studies are limited in stratifying overall risk of arrhythmias. The risk is certainly present as many of these patients have ventricular scar often attributable to cardiac surgeries or have hemodynamic insults that may result in progressive fibrosis of the ventricles.                                 In addition, the basal abnormalities of cardiac formation itself may lend itself to a sudden increased risk of arrhythmias. Thus, the question remains as how to best risk stratify these patients in order to reduce these overall sudden death rates. Changing gears yet again, we'll focus on two articles within the realm of cellular electrophysiology. The first article was published by Cerrone et al. in Nature Communications entitled Plakophilin-2 is Required for Transcription of Genes that Control Calcium Cycling and Cardiac Rhythm.                                 They demonstrated that plakophilin-2, or PKP2, which is known to mediate arrhythmogenic right ventricular cardiomyopathy due to abnormalities in the desmosomes actually has other direct electrical effects independent of substraight effects that are seen. Specifically PKP2 plays a significant role in maintaining gene transcription for several genes that mediate normal electrophysiologic activity, such as the ryanodine receptor, calsequestrin and others.                                 They demonstrated that this reduced expression of other genes secondary to PKP2 absence or abnormality leads to increased isoproterenol or adrenaline-induced arrhythmias that in turn can be suppressed with Flecainide. These findings are provocative in the fact that they suggest that it is possible for patients to have abnormalities of genes such as PKP2 that result in electrical abnormalities independent of the structural abnormalities.                                 Furthermore, it suggests that manifestation of the disease such as catecholaminergic polymorphic ventricular tachycardia may be immediate upstream of typical channels associated with the disease. For example, if PKP2 reduces expression of the ryanodine receptor, this might result in manifestations similar to CPTB in some patients. Along the same lines, Hewitt et al. published in Science Advances regarding deregulated calcium cycling underlies the development of arrhythmia and heart disease due to mutant obscurin.                                 Obscurins are a relatively growing area of interest as these are cytoskeletal proteins that have be associated with both hypertrophic and dilated cardiomyopathy. Similar to the story we just told about PKP2 however, they demonstrated that obscurins, likely through circa 2 and pentameric phospholamban can cause abnormal calcium handling. In fact, they demonstrated that the principle phenotype associated with obscurin abnormalities is one of an electrical abnormality, namely frequent PVCs.                                 In turn, mechanical phenotypes such as cardiomyopathy result in the setting of chronic pathologic stress such as increased afterload, thus these findings demonstrate that genes such as obscurin or PKP2, which are commonly associated with structural or mechanical myopathic processes might have direct independent electrical effects. The story with obscurin raises further question into how this may apply to conditions of PVC-related cardiomyopathy or other such conditions.                                 The other key point about these two areas of interest lie in the fact that it is possible as these genetic abnormalities mediate not just direct substraight elements, but arrhythmogenesis via abnormal channel expression, whether in all patients presenting with such specific genetic abnormalities substraight-based ablation alone will result in reduction of arrhythmia tendency. Of course this remains to be seen and is primarily hypothesis-generating.                                 Next we'll focus on three articles within the area of genetic channelopathies. The first paper was published by Rohatgi et al. in The Journal of the American College of Cardiology entitled Contemporary Outcomes in Patients With Long QT Syndrome. In a large single center practice, they reviewed the results of over 600 patients predominantly affected by LQT1 or LQT2 and demonstrated that after initial evaluation along with treatment based on the individual, done at a highly skilled center, 92% of patients did not experience any breakthrough cardiac events over longterm followup.                                 It was noted however, that the incidence of breakthrough cardiovascular events over longterm followup were far more common in patients who were symptomatic prior to their first evaluation than asymptomatic. In other words, if you were symptomatic prior to your first evaluation, the likelihood of a breakthrough cardiovascular event over longterm followup was as high as 25%, but if you were asymptomatic it was as low as 2%.                                 These data suggest that our overall care of the Long QT patient is improving. However, it also supports that further improvements in care are needed as breakthrough cardiovascular events can continue to occur. It also highlights the importance of close followup of that symptomatic patient in the modern era.                                 The second article was published by Kannenkeril et al. in JAMA Cardiology entitled the Efficacy of Flecainide in the Treatment of Catecholaminergic Polymorphic Ventricular Tachycardia. Flecainide currently carries a class 2A indication according to both the 2015 ENC guidelines and 2013 HRS AHRA APHRS consensus statement for treatment of patients with CPVT who fail max dose beta blockers. A lot of this evaluation however, has been based on retrospective evaluations.                                 Kannenkeril reviewed in a prospective single blind placebo controlled crossover trial the effect of Flecainide on exercise associated arrhythmias in CPTV patients who were already on max tolerated beta blockers and had an ICD. Amongst the 14 patients included of whom 13 completed the study, they showed there was a significant reduction in median ventricular arrhythmia score during exercise and in fact there was complete suppression with Flecainide compared to the placebo of 85%.                                 These findings thus add to the existing literature in terms the potential incremental value of Flecainide in achieving adequate arrhythmia suppression when used in conjunction with maximal tolerated beta blockers. The last article within the realm of genetic channelopathies we'll focus on was published by Yang et al. in The Journal of Physiology entitled A Multi-Scale Computational Modeling Approach Predicts Mechanisms of Female Sex Risk in the Setting of Arousal-Induced Arrhythmias.                                 It is recognized that female gender can increase the risk of Torsades in the setting of both inherited and acquired prolonged QT syndromes. In a combination of experimental and computational approaches, Yang et al. demonstrated that hormone concentrations can partly mediate this risk, specifically as it relates to her-related mutations. They demonstrated testosterone and high progesterone levels provide a protective effect against Torsades. However, estrogen can enhance Torsadogenic potential, particularly in the setting sympathetic stress.                                 They also demonstrated the mechanism by which this likely occurs is due to interaction of estrogen with pore loop or intracavity binding site of the her channel. In fact, on top of this they demonstrated that combined treatment with both estrogen and Dofetilide can simultaneously blockade the pore channel of her. These findings are provocative and hypothesis-generating. In terms of potential future research to further clarify risk for patients, particularly as it may apply to menstruating females who might have varying levels of estrogen, especially when being treated with concomitant QT prolonging agents such as Defetilide.                                 Next we will focus on three articles within the realm of ventricular arrhythmias. The first article was published by Sapp et al. in JACC Clinical Electrophysiology entitled Real Time Localization of Ventricular Tachycardia Origin from the Twelve Lead Electrocardiogram. They presented a methodology for rapidly determining in real time the approximate origin of a ventricular tachycardia using the 12 lead during cardiac ablation.                                 In 38 patients they used a variety of methods that involved multiple linear regression learning methods and demonstrated that a patient-specific regression method using at least 10 training set pacing sites in the individual patient can provide a localization accuracy of the exit site for VT of as much as five millimeters. Furthermore, with additional pacing sites that accuracy could improve further.                                 These findings support the continued utility of the standard 12 lead ECG in localizing the exit site of ventricular tachycardia. Furthermore, it points out the importance of considering that the electrocardiogram can be patient-specific. By using multiple pacing sites, this helps an algorithm learn how a patient-specific heart exists in terms of its electrical propagation potential. Further informing based on a 12 lead of a specific VT approximately where it should be exiting from.                                 The next article we will focus on was published by Muser et al. in again, JACC Clinical Electrophysiology entitled Longterm Outcomes of Catheter Ablation of Electrical Storm in Nonischemic Dilated Cardiomyopathy COMpared with Ischemic Cardiomyopathy. The summary point to this article is in a single center, large volume group of patients including about 267 total, the longterm outcomes of VT recurrence or mortality was no different between nonischemic and ischemic patients.                                 This is important to note as most prospective studies and in fact retrospective studies of the role of ventricular tachycardia ablation have focused on ischemic patients where the substraight is relatively predicable. These findings highlight that ablation may provide a reasonably effective therapy irrespective of the cause of the myopathy. Finally, changing gears within the realm of ventricular arrhythmias, we'll focus on a translational article by Motloch et al. in JACC Basic to Translational Science entitled Increased Afterload Following Myocardial Infarction Promotes Conduction-Dependent Arrhythmias That Are Unmasked by Hypokalemia.                                 They studied the role of increased afterload after myocardial infarction in a listing arrhythmias in a porcine infarct model. They demonstrated that in the setting of increased afterload there was increased widespread interstitial fibrosis. Interestingly, pacing -induced arrhythmias induced by a rapid burst pacing were mediated by hypokalemia associated conduction abnormalities rather than repolarization abnormalities.                                 The reason these findings are potentially important lie in the fact that arrhythmias in the early stages after myocardial infarction, especially in a setting of increased afterload, might be considered to be secondary to either repolarization abnormalities or depolarization abnormalities. These findings suggest that in the setting of concomitant hypertension the primary problem really lies in hypokalemia associated conduction abnormalities.                                 Thus, treatments that impair cardiac excitability, for example, even sodium channel blockade, may similarly confer an increased risk of ventricular arrhythmias when in the presence of increased afterload and myocardial infarction. It also calls into question whether interventions such as antitachycardia pacing in patients with hypertension, in other words increased afterload, might be more prone to acceleration of the ventricular arrhythmias than patients who are relatively better managed as far as afterload.                                 Changing gears yet again, we will focus on EP relevant myopathies. [inaudible 00:44:19] et al. published in JACC Clinical Electrophysiology regarding use of the 12 lead electrocardiogram to localize regions of abnormal electron atomic substraight in arrhythmogenic ventricular cardiomyopathy. There were really two major articles in this regard that have been published both in the same month.                                 The other article was published by Andrews et al. in Circulation, Arrhythmia and Electrophysiology entitled Electrical and Structural Substraight of Arrhythmogenic Right Ventricular Cardiomyopathy Determined Using Noninvasive Electrocardiographic Imaging and Late Gadolinium Magnetic Resonance Imaging.                                 The relevance of both of these articles lies in their statements about the potential utility of noninvasive approaches essentially using electrocardiograms to determine the distribution of substraight in arrhythmogenic right ventricular cardiomyopathy. The article by [inaudible 00:45:16] et al. specifically focused on fractionation of the QRS. They showed that patients with evidence of fractionation in the QRS on a 12 lead ECG had more extensive substraight.                                 Furthermore, distribution of fractionation to specific leads such as inferior, anterior or basal superior leads, was 100% specific, but veritably sensitive for identifying substraight as it localizes to specific cardiac regions. In turn, the publication by Andrews et al. in Circulation, Arrhythmia and Electrophysiology reviewed how the addition of multiple leads by a noninvasive electrocardiographic imaging could be used to even more specifically hone in on the relevant substraights.                                 Their further benefit was in the suggestion that repolarization abnormalities in fact co-localized with origination sites for ventricular ectopy in these patients. In combination, these sites highlight the utility of simple, noninvasive methods of electrocardiographic imaging in identifying and defining the arrhythmogenic substraight in the NRVC.                                 The next article we will review was by Sommariva et al. in Nature's Scientific Reports published just this past month entitled MIR 320A as a Potential Novel Circulating Biomarker of Arrhythmogenic Cardiomyopathy. They did micro RNA analysis on 53 healthy controls, 21 idiopathic VT patients and 36 arrhythmogenic cardiomyopathy patients and demonstrated that the circulating micro RNA 320A was significantly higher in arrhythmogenic cardiomyopathy than in either other cohorts.                                 It is recognized that some patients with idiopathic VT, especially right ventricular [inaudible 00:47:09] VT might reflect a cohort that might have what we call "concealed ARVC." The question thus becomes how to define why a patient has a specific manifestation of disease because longterm outcomes, if there is some underlying ARVC might be worse if the ARVC is not recognized and if cure is assumed based on treatment of the initial presenting rhythm.                                 Thus identifying novel ways of defining the presence of a disease even in the absence of obvious structural abnormalities carries benefit in terms of suggestions on longterm followup. Complimentary to the previously discussed article on the role of PKP2 mutations on mediating electrical instability in the heart, the study by [inaudible 00:48:01] et al. does in fact suggest that there might be methods of distinguishing arrhythmogenic cardiomyopathy from whether it be controls or truly idiopathic ventricular tachycardia using a very specific circulating biomarker.                                 On a completely different route, we'll finish our podcast today with a discussion of Bruner et al. published in European Heart Journal entitled Alcohol Consumption, Sinus Tachycardia and Cardiac Arrhythmias at the Munich Oktoberfest: Results from the Munich Beer-Related Electrocardiogram Workup Study or Munich Brew.                                 Bruner et al. studied over 3,000 voluntary participants with a combination of breath alcohol concentration measurements and electrocardiographic recordings via smartphone throughout the Munich Oktoberfest. In addition, they sought to evaluate chronic alcohol consumption effects on arrhythmias in a separate cord of over 4,000 patients from the Cora S4 study. In the study regarding acute alcohol effects, they demonstrated that in line with increasing BAC, there was a greater occurrence of arrhythmias in particular sinus tachycardia in almost a third of patients.                                 What was even further interesting was that respiratory sinus arrhythmia over the course of higher BAC is from baseline was reduced in the setting of alcohol use. Similarly, with chronic alcohol consumption there was an apparent significant association with the occurrence of sinus tachycardia. The reason these findings are important is in their suggestive element that the effects of alcohol intake in terms of whether it be acute or chronic arrhythmogenesis might somewhat lie in their effects on the basal autonomic states. As demonstrated by the reduction in overall sinus arrhythmia.                                 These findings serve to further elucidate mechanisms by which alcohol may mediate arrhythmias in a large real world patient sample. Thank you for joining us on this edition of On The Beat. Tune in next month again for more articles that might be of interest to the general electrophysiologic community all summarized in a single location.

Commentary by Dr. Valentin Fuster

Commentary by Dr. Valentin Fuster

In this NewsFlash, we discover a faster and cheaper way to make bespoke computer chips, find out how stem cells can help understand Long QT Syndrome and explore the problem of feeding a growing global population. Plus, how new live performance beat-tracking software puts the drummer back in the driving seat!

Jedes Jahr sterben in Deutschland zirka 80 - 100.000 Menschen an einem plötzlichen Herztod. Das sind ca. 10 % aller Todesfälle. Bei zirka 10 % der Betroffenen können keine ursächlichen strukturellen Herzerkrankungen erfasst werden. Zu dieser Gruppe gehören genetisch bedingte Arrhythmiesyndrome, wie das Long-QT-Syndrom und das Brugada-Syndrom. Obwohl bisher eine Vielzahl von Mutationen beim LQTS und Brugada-Syndrom identifiziert wurden, sind nur wenige funktionell charakterisiert worden. Große Studien zur Genotyp-Phänotyp Korrelation dieser beiden Erkrankungen basierten bisher auf retrospektiven klinischen Untersuchungen und der Lokalisation nachgewiesener Mutationen. In der vorliegenden Arbeit wurde eine Strategie zur systematischen Untersuchung der Genotyp-Phänotyp-Korrelation bei LQTS und Brugada-Syndrom an vier Patienten mit überlebtem plötzlichen Herztod dargestellt. Durch die funktionelle Expression und elektrophysiologische Untersuchung der identifizierten Mutationen lassen sich individuelle Aussagen über die funktionellen Auswirkungen der Mutation treffen.

On Friday, September 29th, 2-year Colorado Av Steve Konowalchuk (#22) announced that he will retire. This comes after an abnormal pre-training camp EKG showed abnormalities. This was later confirmed to be Long QT Syndrome, a genetic disease. There is also a player on the Detroit Red Wings that had this same disease. If your think back to last year a player had a heart attack while on the bench at a game, Long QT is suspected to be the culprit. Visit our forums http://www.z10.invisionfree.com/AVScast_Forum. The show notes are at http://www.geocities.com/udtmnshownotes (we did upgrade the eye candy-ness of them this morning.) Please give us feedback at feedback@AVScast.com

Thu, 10 Oct 2002 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/755/ https://edoc.ub.uni-muenchen.de/755/1/Seidel_Juergen.pdf Seidel, Jürgen ddc:610, ddc:600, Medizinische Fakultät