Podcasts about scn5a

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

This week, please join author Xuerong Wen, Associate Editor Sandeep Das, and Guest Host Mercedes Carnethon as they discuss the article "Comparative Effectiveness and Safety of Direct Oral Anticoagulants and Warfarin in Patients With Atrial Fibrillation and Chronic Liver Disease: A Nationwide Cohort Study." Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass of 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 Poly Heart Center at VCU Health in Richmond, Virginia. Dr. Carolyn Lam: Greg, I'm so excited about today's feature paper. It deals with the important condition where atrial fibrillation exists in patients with chronic liver disease and what do we do for anticoagulation in these patients. It's a comparative effectiveness and safety study of direct oral anticoagulants compared with warfarin in these patients. A huge, wonderful, important study that we're going to discuss. But before we get there, I'd like to tell you about some papers in this issue and I'd like you to tell me about some too. You got your coffee? Dr. Greg Hundley: Absolutely. Dr. Carolyn Lam: All right. I'll go first In this paper that describes a quantitative prognostic tool for the mitral valve prolapse spectrum and it's derived from the new mitral regurgitation international database quantitative or MIDA-Q registry, which enrolled more than 8,000 consecutive patients from North America, Europe, Middle East. And these were patients all diagnosed with isolated mitral valve prolapse or MVP in routine clinical practice of academic centers, all of which also did prospective degenerative mitral regurgitation quantification. The MIDA-Q score was calculated based on characteristics collected in routine practice combining the established MIDA score, which integrated guideline based markers of outcomes like age, New York Heart Association status, atrial fibrillation, LA size, pulmonary artery pressure left ventricular and systolic, I mentioned, and ejection fraction. Integrating that with scoring points based on the degenerative mitral regurgitation quantitation that is measuring effective regurgitant orifice and volume. Dr. Greg Hundley: Very interesting Carolyn. So a scoring system that combines clinical information with what we might assess with echocardiography like regurgitant volume or regurgitant orifice area. So how well did this mortality risk score perform? Dr. Carolyn Lam: So the new score was associated with an extreme range of predicted survival under medical management and that ranged from 97% to 5% at five years for the extreme score ranges. And it was strongly, independently and incrementally associated with long-term survival over all the markers of outcomes. So the authors concluded, and these by the way were authors led by Dr. Maurice Serrano from Mayo Clinic, Rochester, Minnesota. These authors concluded that the score should allow integrated risk assessment of patients with mitral valve prolapse to refine clinical decision making in routine practice and ultimately reduce degenerative mitral regurgitation under treatment. Dr. Greg Hundley: Wonderful description Carolyn. Well I'm going to switch to the world of electrophysiology, Carolyn. And so as you know, the Brugada syndrome is an inherited arrhythmia syndrome caused by loss of function variants in the cardiac sodium channel gene SCN5A and that occurs in about 20% of subjects. And these authors led by Dr. Dan Roden at Vanderbilt University School of Medicine identified a family with four individuals diagnosed with Brugada syndrome, harboring a rare missense variant in the cardiac transcription factor, TBX5, but no SCN5A variant. And upon identifying these individuals, their objective was to establish TBX5 as a causative gene in Brugada syndrome and to define the underlying mechanisms by which it would be operative. Dr. Carolyn Lam: Oh wow. So a new gene variant. So what was the relationship? Dr. Greg Hundley: Right Carolyn? So using induced pluripotent stem cell derived cardiomyocytes from members of the affected family, multiple electrophysiologic abnormalities were detected in these cardiomyocytes including decreased peak and enhanced late cardiac sodium current. In these cells these abnormalities were entirely corrected by CRISPR/Cas9 mediated editing of that TBX5 variant and transcriptional profiling and functional assays in unedited and edited pluripotent stem cell derived cardiomyocytes showed direct SCN5A down regulation caused decreased peak sodium current and that reduced PDGF receptor expression and blunted signal transduction to phosphoinositide-3-kinase. And interestingly, PDGF receptor blockade markedly prolonged normal induced pluripotent stem cell derived cardiomyocyte action potentials. And also Carolyn interestingly in this study they did a separate analysis. It reviewed plasma levels of PDGF in the Framingham Heart Study and they found that they were inversely correlated with the QT corrected interval. And so Carolyn, these results established decrease SCN5A transcription by the TBX5 variant as a cause of Brugada syndrome and also reveal a new general transcriptional mechanism of arrhythmogenesis of enhanced late sodium current caused by reduced PDGF receptor mediated phosphoinositide-3-kinase signaling. Dr. Carolyn Lam: Wow. Wow, that's significant. Thanks Greg. So this next paper is also really important and could change the practice in the field of cardiac resynchronization therapy or CRT. You see, it suggests that the practice of what we do now, which is combining right bundle branch block with intraventricular conduction delay patients into a single non-left bundle branch block category when we select patients for CRT, that this may not be the way to go. So let's go back a bit and remember that benefit from CRT varies with QRS characteristics and individual trials are actually underpowered to assess the benefit for relatively small subgroups. So the current authors led by Dr. Friedman from Duke University Hospital and colleagues, therefore performed a patient level meta-analysis of randomized trials of CRT to assess the relationship between QRS duration and morphology with outcomes. Dr. Greg Hundley: Very interesting Carolyn. So another wonderful paper from the world of electrophysiology in trying to understand optimal mechanisms to resynchronize the ventricle in patients with differing bundle branch blocks or intraventricular conduction delays. So what did they find? Dr. Carolyn Lam: They found that patients with intraventricular conduction delays and a QRS duration of 150 milliseconds or more, CRT was associated with lower rates of heart failure hospitalizations and all cause mortality. The magnitude of CRT benefit among these patients with the interventricular conduction delay of 150 milliseconds or more and those with the left bundle branch block of 150 milliseconds or more were similar. In contrast, there was no clear CRT benefit for patients with a right bundle branch block of any QRS duration, although the authors could not rule out the potential for benefit at a markedly prolonged QRS duration. So they concluded that the practice of combining right bundle branch block with intraventricular conduction delay patients into a single non-left bundle branch block category when we make patient selections for CRT is not supported by the current data. And in fact, patients with an intraventricular conduction delay of 150 milliseconds or more should be offered CRT as is done for patients with a left bundle branch block of 150 milliseconds or more. Dr. Greg Hundley: Wow, Carolyn, so really interesting point. No clear CRT benefit for patients with right bundle branch block regardless of the QRS duration. Well we've got some other articles in the issue. I'll describe a couple from the mail bag. There's a Research Letter from Professor Lassen entitled "Risk of Incident Thromboembolic and Ischemic Events Following COVID-19 Vaccination Compared with SARS-COV2 Infection." Also Bridget Kuhn has a wonderful Cardiology News piece entitled "Collaborative Care Model Helps Heart Failure Patients Meet End-of-Life Goals." Dr. Carolyn Lam: There's an exchange of letters between Doctors Donzelli and Hippisley-Cox regarding that risk of myocarditis after sequential doses of COVID-19 vaccine, there's an AHA Update by Dr. Churchwell on continuous Medicaid eligibility, the lessons from the pandemic. There's an On My Mind paper by Dr. Parkhomenko on Russia's war in Ukraine and cardiovascular healthcare. Wow, what an issue. Thanks so much, Greg. Shall we go on to the feature discussion? Dr. Greg Hundley: You bet. Dr. Mercedes Carnethon: Well welcome to this episode of Circulation on the Run podcast. I'm Mercedes Carnethon, associate editor of the journal Circulation and Professor and Vice Chair of Preventive Medicine at the Northwestern University Feinberg School of Medicine. I'm very excited to be here today with Xuerong Wen and Sandeep Das, my fellow associate editor here at Circulation to talk about a wonderful piece by Dr. Wen and colleagues from the University of Rhode Island. So welcome this morning Xuerong and thank you so much for sharing your important work with us. Dr. Xuerong Wen: Thank you Dr. Carnethon. It was great meeting you all and I'm the Associate Professor of Pharmacoepidemiology and Health Outcomes at the University of Rhode Island. I'm happy to introduce my study to everyone. Dr. Mercedes Carnethon: Well thank you so much and thank you as well Sandeep for identifying this fantastic article and bringing it forth. Dr. Sandeep Das: Thanks Mercedes. It's great to be with you. Dr. Mercedes Carnethon: Great. Well let's go ahead and get into it. There's so much here to talk about. So Dr. Wen and colleagues studied the comparative effectiveness and safety of direct oral anticoagulants or DOACs and warfarin in patients with atrial fibrillation and chronic liver disease. So this is such an important topic. Can you tell us a little bit about what your study found? Dr. Xuerong Wen: So our study is a comparative effectiveness and the safety analysis using a national health administrative data from private health plans. So we compared the risk of hospitalized ischemic stroke, systemic embolism and major bleeding between DOACs and warfarin in patients with atrial fibrillation and chronic liver disease. So we also had to had compare to these primary outcomes between apixaban and rivaroxaban in the study population. So our studies show that among patients with atrial fibrillation and chronic liver disease, DOACs as a class was associated with lower risk of hospitalization of ischemic stroke and systemic embolism and major bleeding, compared with warfarin. And when compared risk outcomes between individuals apixaban has lower risks as compared to rivaroxaban. So that's our study results. Dr. Mercedes Carnethon: Well thank you so much. This seems like such an important question. We hear a lot about DOACs and some of their risks as well as their considerable benefits. I think what leaves me the most curious is why did you choose to pursue this question and in particular in patients with both atrial fibrillation and liver disease. So why was the intersection of these two particular conditions of interest to your study team? Dr. Xuerong Wen: That's a great question. So the liver actually plays a central role in both the synthesis of coagulation factors and the metabolism of anticoagulant drugs. And the clearance of the anticoagulants in liver ranges from 20% to 100% for DOACs and warfarin. So in clinical practice anticoagulation abnormalities and elevated risk of spontaneous or unprovoked venous thrombotic complications have been reported in patients with liver disease. While these patients with cirrhosis were excluded from the clinical trials of DOACs and also population based, the real world experience is very limited. So that is why we initiated this retrospective cohort study and based on the real world data in this specific population. Dr. Mercedes Carnethon: Oh, thank you so much for explaining that. I definitely learned a lot and really enjoyed reading the piece. I think it was very well organized and well written and I know that our readership will appreciate it. It obviously stood out to you as well, Sandeep. Can you tell me a little bit about why you thought that this would be an excellent piece for circulation? Dr. Sandeep Das: Yeah, absolutely. Thanks for the question. So in the broad field of what we call observational comparative effectiveness research, so basically that's using large observational data sets to try to answer important clinical questions and it's a really challenging thing to do. I mean we're all very familiar with the idea of using randomized trials to assess important clinical questions because of the structure of that design allows you to mitigate some of the effects of confounding. Here, it has to be done analytically. So what's the important factor that really drives you towards a great observational comparative effectiveness piece? So first the clinical importance. I feel a little guilty because I'm old enough to remember when warfarin was the only option available, but really as a clinician, or every patient, I really prefer DOACs over warfarin just for ease of use and lifestyle. So there's a huge sort of importance to the question. Second, the patients with chronic liver disease were excluded from the larger RCTs and the DOAC trials. So really we don't have the answer to the question already. It's an important question. Obviously the bleeding risk is tied up with the liver, warfarin directly antagonizes vitamin K, so there's real questions about safety and so this is the perfect storm and then on top of it was a really well done and well executed study. So when this came across my desk, the very first thing I thought was not, "Is this something that we're interested?" But rather, "How do we make it better? How do we make it more useful to the reader?" This had me from hello. Dr. Mercedes Carnethon: Well thanks so much. We rarely have the opportunity when we read an article to be able to ask the authors questions. So Sandeep, I know that you had mentioned that you had some follow up questions as well. Dr. Sandeep Das: Yeah. So the real thought that I have then is would you argue based on this that we know enough that we should change our practice? And that do you feel comfortable advocating that people now prescribe DOACs to these patients? Dr. Xuerong Wen: I would say yes. Okay. Although this is not a clinical trial, but our study is actually systematically compare the effectiveness and safety between DOAC users and also the warfarin users. And if you look at our table one, we compare with so many variables between these two users and we use the propensity score adjustment and we after propensity score weighting and the two control group almost balanced. And I know right now FDA actually suggested that emulate the trial using the large real world data to do the emulated trial. So our study actually conducted is based on the large population using large data and we use the propensity score weighting to control all this potential compounding factors. Although there are still some limitations in this study. I think we mentioned that in the discussion section and we discussed all potential compounding factors that still may exist. And also there are some misclassifications and out of all this limitations and we still found the two drugs performed differently in this specific population. So we feel that comfortable to say that a DOAC drug performs better than warfarin. And also I think based on other studies that based on the clinical trial in the general population, DOAC drug is performs much better than warfarin and considering that the clearance in liver for DOAC is less than warfarin. So plus all this information together, I think DOAC may be safer than wafarin in the patients with AF and chronic liver disease. Dr. Sandeep Das: Yeah, I would say that I agree that these data, even if you're skeptical about observational CT generally, which I admit that I tend to be, these are really reassuring data that at least the DOACs are... There's absolutely nothing that suggests that they're any worse than warfarin and all of the sort of soft indications for ease of use and patient happiness really would seem to favor DOACs. So I think this is the sort of rare observational CT paper that may actually change my practice. Dr. Mercedes Carnethon: I have a follow-up question, Xuerong, related to the design and as well your strategy to address differences between the groups. So inverse probability weighting is certainly a standard in the field to be able to manage differences between groups when you have a situation where can't, where it's not a randomized trial. Do you as well, and educate me, I admit I'm an epidemiologist whose methodological skills are sometimes challenged. Do you have the opportunity using this design and with inverse probability weighting to evaluate subgroup effects? So my specific question is were you able to determine whether or not these associations were similar based on age and gender in particular? Dr. Xuerong Wen: That's a great question. We did conducted a lot of subgroup study but not by age or gender. We conducted I think this study in a lot of subgroups using the propensity score weighting, but the subgroup that I think we did a subgroup like a patient with a different chronic liver disease. So that's what we did. And we also tested different methods inverse probability score weighting. So we did trimming and we used a different percentage of trimming and to see how that affect the study results. So we have done a lot of subgroup studies. We did not check the age and the gender, but that's a very good point. Maybe later, well I'll ask my student to do that. Dr. Mercedes Carnethon: Well, you're a good mentor. So I think that is a really certainly an appropriate approach. Sandeep, did you have additional questions? Dr. Sandeep Das: No, I wish I had thought of yours before you did. I think exactly the older age, women, racial ethnic groups that are underrepresented historically in trials. I think that that's really, again, the sweet spot of this observational research. We definitely, and NH definitely working on trying to increase enrollment of all these groups in our CTs. However, while we wait for that, I think that's exactly what we should be doing. Dr. Mercedes Carnethon: Well that's great. And Xuerong, you really alluded to really, I think what is one of my final questions related to what do you think based on what you have observed in this study, what do you see as the next steps in the research field for your team, your students, or other people who are carrying out this type of work? Dr. Xuerong Wen: Well, that's a great question. We currently have a couple of more manuscripts ongoing in this field, and we will continue conducting the comparative effectiveness and analysis to compare drugs head to head as well as developing and implementing new methodologies to this field. And we hope our study provides real world evidence for clinical decision making, prescribing anticoagulants to patients with atrial fibrillation and chronic liver disease. We also expect the physicians and researchers more and more value the real world data studies, especially when clinical trials are not feasible or ethical. Dr. Mercedes Carnethon: Well, thank you so much. That was such an excellent vision that you provided us with and we're just very grateful that you submitted this fantastic work to the journal Circulation. I know that our readers will enjoy really digging in. The podcast is meant as a teaser to bring you to the journal so that you can read about this wonderful work by Dr. Wen and colleagues. So again, thank you. I'm Mercedes Carnethon, joined with my associate editor partner here, Dr. Sandeep Das. And thank you very much for spending your time with us today, Dr. Wen. Dr. Xuerong Wen: Thanks for this great opportunity to disseminate my study with us, thank you. Dr. Sandeep Das: Thanks Mercedes. Dr. Mercedes Carnethon: Thank you for joining us for this episode of Circulation on the Run. Dr. Greg Hundley: This program is copyright of the American Heart Association 2023. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.

The field of Cardiovascular Genomics has advanced tremendously over the past two decades, having a significant clinical impact and changing the perception of the role and scope of genetic testing in several cardiovascular domains.  To kickstart the Cardiovascular Genomics series, CardioNerds Dr. Sara Coles (FIT at Duke University), Dr. Colin Blumenthal (CardioNerds Academy faculty and FIT at UPenn), and Dr. Karla Asturias (CardioNerds Academy fellow and medicine resident at Pennsylvania Hospital) have a great discussion with Dr. James Daubert, a clinical electrophysiologist at Duke University, with a particular interest in inherited arrhythmia syndromes and sports cardiology. In this episode, we review basic concepts of cardiovascular genomics and genetics in electrophysiology while discussing when to (and when not to!) test our patients and their families and how to approach those results. Audio editing by CardioNerds academy intern, Pace Wetstein. This episode was developed in collaboration with the American Society of Preventive Cardiology and is supported with unrestricted educational funds from Illumina, Inc. All CardioNerds content is planned, produced, and reviewed solely by CardioNerds. This CardioNerds Cardiovascular Genomics series is a multi-institutional collaboration made possible by contributions of stellar fellow leads and expert faculty from several programs. Pearls • Notes • References CardioNerds Cardiovascular Genomics PageCardioNerds Episode PageCardioNerds AcademyCardionerds Healy Honor Roll CardioNerds Journal ClubSubscribe to The Heartbeat Newsletter!Check out CardioNerds SWAG!Become a CardioNerds Patron! Pearls and Quotes - Genetics in Electrophysiology The first step is identifying the right phenotype! Getting the right phenotype is crucial, as genetic testing done in a patient without a clear phenotype (or an incorrect one) would lead to significant anxiety, unnecessary tests and interventions, and potentially misleading and dangerous conclusions for patients and their families. Genetic testing typically should be reserved for patients with a confirmed or suspected diagnosis of an inherited disease or for individuals with a previously diagnosed pathogenic variant in a first-degree relative.1 Discuss with your patient! Genetic counseling is essential and recommended for all patients before and after genetic testing. It should include a thorough discussion of risks, benefits, and possible outcomes, including variants of uncertain significance.2 Cardiovascular genetics is a dynamic and rapidly evolving field. New information can cause a variant of uncertain significance to be reclassified as a pathogenic or likely pathogenic variant or to be downgraded to benign or likely benign as variant databases expand. Another possibility is that new research might identify novel genes for a particular disease, which could warrant retesting, particularly for phenotype-positive and genotype-negative patients.1 Brugada syndrome is an inherited arrhythmogenic disorder characterized by ST-segment elevation in the right precordial leads and malignant ventricular arrhythmias, with occasional conduction disease and atrial arrhythmias. It is diagnosed in patients with ST-segment elevation ≥ 2 mm in ≥ 1 lead among the right precordial leads, with a type I morphology (J-point elevation with slowly descending or concave ST segment elevation merging into a negative T wave), shown in the image below. This pattern can be observed spontaneously or after provocative drug testing (e.g., procainamide). Pathogenic genetic variants in SCN5A that result in loss of function of the cardiac sodium channel are identified in approximately 20% of cases.3,4 Image adapted from Batchvarov VN. The Brugada Syndrome – Diagnosis, Clinical Implications and Risk Stratification. Eur Cardiol Rev. 2014;9(2):82. doi:10.15420/ECR.2014.9.2.82 Measure the QT interval yourself!

Please join authors Christopher Granger and Anthony Carnicelli, as well as Associate Editor & Editorialist Shinya Goto as they discuss the article "Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation: Patient-Level Network Meta-Analyses of Randomized Clinical Trials With Interaction Testing by Age and Sex" and accompanying Editorial "Patient Level Meta-Analysis: End of the Era for DOAC Developmental Trial in AF Patients?" 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 Nam, 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 at VCU Health in Richmond, Virginia. Dr. Carolyn Lam: Greg, I'm so excited about our feature discussion today. It is about DOACs versus warfarin in patients with atrial fibrillation, a really important patient-level network meta-analysis of randomized control trials with interaction testing by agent six. So you can already tell something very, very clinically relevant and important discussed by not only the authors, but our dear associate editor and editorialist. Dr. Carolyn Lam: Okay. You just got to tune in, but first I'm going to start us off with some coffee, as well as a description of this first paper in today's issue. The 2018 AHA ACC multi-society cholesterol guidelines states that statin therapy may be withheld or delayed among intermediate risk individuals in the absence of coronary artery calcium. Dr. Carolyn Lam: However, two traditional cardiovascular risk factors associate with incident atherosclerotic cardiovascular disease events among individuals with zero coronary artery calcium over the long term? Well, this is the question that investigators decided to answer in today's paper and they're led by Dr. Virani from Baylor College of Medicine in Houston, Texas. Dr. Carolyn Lam: They studied 3,416 individuals with coronary artery calcium score of zero at baseline from the MESA study, which is a prospective cohort study of individuals free of clinical atherosclerotic cardiovascular disease at baseline. Among these individuals with zero coronary artery calcium, cigarette smoking, diabetes and hypertension were found to be independently associated with incident atherosclerotic cardiovascular disease events over long-term follow up. Dr. Greg Hundley: Ah, very interesting. Another piece of information relating to how we might use coronary artery calcium scores in, it sounds like, a high-risk patient population. So, Carolyn, what's the take-home message here? Dr. Carolyn Lam: Well, even if individuals have a coronary artery calcium of zero, if they are current smokers, if they have diabetes melitis or hypertension, initiation and long-term use of statin therapy, along with a heart healthy lifestyle and risk factor modification may still be warranted as part of the patient/clinician risk discussion. Dr. Greg Hundley: Very interesting Carolyn. Well, I've got a clinical study to tell you about. And, Carolyn, as you know, obesity and diabetes are associated with a higher risk of heart failure and the inner relationships between different measures of adiposity, including overall obesity, central obesity, fat mass, and diabetes status for heart failure risk, are not well established. Dr. Greg Hundley: And so this investigative group, led by Dr. Ambarish Pandey, from UT Southwestern Medical Center, looked at the ARIC, the visit five in ARIC and CHS, the visit one, and cohorts together, and they were obtained from the NHLBI BioLINCC. They were harmonized and pooled for the present analysis, excluding individuals with prevalent heart failure. Dr. Greg Hundley: So using multi-variable adjusted fine-grade model models were created to evaluate the associations of body mass index, waist circumference, and fat mass with risk of heart failure in the overall cohort, as well as among those with, versus without, diabetes at baseline. Dr. Greg Hundley: And the population attributable risk of overall obesity with BMI greater than 30 kilograms per meter squared, abdominal obesity with waist circumference greater than 88 and 102 centimeters in women and men, respectively, and high fat mass above the sex-specific median for incident heart failure, was evaluated among participants with and without diabetes. Dr. Carolyn Lam: Ooh, I'm so in interested in this topic. So what did they find, Greg? Dr. Greg Hundley: Right, Carolyn. So a large study, it included 10,387 participants, about 53% from ARIC, 25% had diabetes, and the median age was 74 years. And higher levels of each adiposity measure were significantly associated with higher heart failure risk. The population-attributable risk percentage of overall obesity, abdominal obesity, and high fat mass for incident heart failure was higher among participants with diabetes versus those without diabetes. Dr. Greg Hundley: And so, Carolyn, we can conclude from this research that higher BMI, higher waist circumference and higher fat mass, are strongly associated with greater risk of heart failure among older adults, particularly among those with prevalent diabetes. Dr. Carolyn Lam: So, so nicely done. Thank you, Greg. Well, the next paper talks about common ancestry-specific ion channel variants and how they predispose to drug-induced arrhythmias. Now, we know that multiple reports associate the cardiac sodium channel gene Scn5a variants, and these are the specific variants, S1103Y and R1193Q, with Type 3 congenital long QT syndrome and drug-induced long QT syndrome. Dr. Carolyn Lam: These variants are, however, two common in ancestral populations to be highly arrhythmogenic at baseline. The S1103Y allele frequency, for example, is 8.1% in Africans and the R1193Q is 6.1% prevalent in East Asians. So the investigators, led by Dr. Roden from Vanderbilt University Medical Center in Nashville, Tennessee, and colleagues, determined the effect of the S1103Y variant on QT intervals among 1,479 Africans from a large electronic health record with no confounding medications or diagnosis of heart disease. Dr. Carolyn Lam: Now, while both the specific variants generated increased late sodium current, baseline action potential durations in cardiomyocytes from induced pluripotent stem cells carrying these variants were unexpectedly normal. The re-polarizing potassium current, IKR, was markedly increased in these induced pluripotent stem cells with the variants, accounting for normal baseline action potential duration but, with exposure to an IKR blocker, they displayed exaggerated action potential duration prolongation and after depolarizations. Dr. Greg Hundley: Wow, Carolyn, interesting. So tell us, what are the clinical implications of this really exciting research? Dr. Carolyn Lam: Yeah. So here's the take-home message. These common ancestry-specific variants do not affect baseline re-polarization, despite generating an increased late sodium current. So the authors propose that increased re-polarizing potassium current, IKR, serves to maintain normal re-polarization, but increases the risk of manifest QT prolongation with IKR blocking in these variant carriers. So we need to be aware of that and, further, these findings highlight the need to include ancestral diversity in genomic and pharmacogenomic studies. Dr. Greg Hundley: Oh, wow. Beautifully described, Carolyn. I really appreciate that. Just excellent discussion. Well, Carolyn, my next paper comes to us in an investigation regarding doxorubicin or anthracycline-associated induced cardiotoxicity. So, Carolyn, multiple pharmacogenetic studies have identified the synonymous genomic variant rs7853758 and the intronic variant rs885004 and SLC28A3 as statistically associated with a lower incidence of anthracycline-induced cardiotoxicity. Dr. Greg Hundley: However, the true causal variant, or variance, of this cardioprotective mechanism at this locus, the role of SLC28A3 and other solute carrier transporters in anthracycline-induced cardiotoxicity and the suitability of solute carrier transporters as targets for cardioprotective drugs has not been investigated. Dr. Carolyn Lam: Wow. Got it. So what did these investigators do and find, Greg? Dr. Greg Hundley: Right. So Paul Burridge and his colleagues at Northwestern University found that the patient-specific cardiomyocytes recapitulate the cardioprotective effect of the cGAS-identified SLC28A3 locus, and the authors functionally confirmed for the first time, the role of SLC28A3 in doxorubicin-induced cardiotoxicity. Dr. Greg Hundley: And a novel genetic variant, the rs11140490, is the potential causal variant in the SLC28A3 cardioprotective locus. And finally, Carolyn, the solute carrier transporter inhibitor desipramine protects against doxorubicin-induced cardio toxicity through decreasing the intracellular uptake of doxorubicin into the heart. Dr. Carolyn Lam: Wow. That is a lot of data. Could you summarize it for us, Greg? Dr. Greg Hundley: Right, Carolyn. So these investigators provide two potential therapeutic options to attenuate doxorubicin-induced cardiomyopathy, either repurposing FDA-approved desipramine, or therapy with long non-coding RNA SLC28A3-AS1. Also, Carolyn, they propose that a simple clinical test to detect the presence of rs11140490 can be used to predict that a patient will be less likely to experience doxorubicin-induced cardiomyopathy, and that, perhaps with future clinical trials, it may be possible for these patients to be treated with a longer duration, that is a higher accumulative dose of doxorubicin, to enhance the efficacy of their chemotherapy. Dr. Carolyn Lam: I love the way you took that home for us. Thank you, Greg. Well, also in today's issue is a Research Letter by Dr. Chen on multifaceted spacial and functional zonation of cardiac cells in an adult human heart. Dr. Greg Hundley: Right, Carolyn. And Professor Constantine has a Letter to the Editor entitled Pravastatin Versus Placebo in Pregnancies at High Risk of Term Preeclampsia. Well, Carolyn, how about we get onto that feature article and learn about DOACs versus warfarin in this very large network meta-analysis? Dr. Carolyn Lam: Yes, yes, yes. Let's go, Greg. Thanks. Dr. Greg Hundley: Welcome, listeners, to our feature discussion today. And we're very fortunate. We're going to review the utility of DOACs in patients with atrial fibrillation. And we have with us two of the authors of this original research, Dr. Anthony Carnicelli from Duke University, and Dr. Chris Granger from Duke University. Dr. Greg Hundley: Additionally, we have with us our associate editor, Dr. Shinya Goto, from Japan. Welcome, gentlemen. Anthony, we'll start with you. Describe for us a little of the background information pertaining to your study and what was the hypothesis that you wanted to address? Dr. Anthony Carnicelli: Yeah, thanks so much, Greg, for having us here to discuss this. I started working in the DOAC space when I was a resident at Brigham and Women's Hospital with mentorship from Dr. Bob Guigliano there, and was really fortunate to connect with Dr. Granger when I came to Duke for a fellowship, and we had this unique opportunity to take data out of the four largest trials of anticoagulants in the atrial fibrillation, and take individual patient data from these international centers and combine them to form the combined AF database from which we did this analysis. Dr. Anthony Carnicelli: So a very unique opportunity here to have individual patient-level data from over 70,000 patients, and perform this analysis. And, really, what we aimed to do was to do the kind of highest quality meta-analysis using network meta-analysis methods to investigate the relative safety and efficacy of DOACs versus warfarin and a broad and diverse, but randomized, population of patients with atrial fibrillation. Dr. Greg Hundley: Very good. So you started to describe for us your study population and your study aligns. So tell us a little bit more, who were these patients, and then maybe specifically give us a little bit of the outline of your meta-analysis. Dr. Anthony Carnicelli: Yeah, so these were, again, a very broad patient group, but from kind of 10,000 feet, this was a population of patients with atrial fibrillation who were at risk of stroke, from CHADS score perspective. So there are some nuances from each of the included studies, of course, regarding the individual risk of stroke from one study to the next. But largely, as I mentioned, in patients with non-valvular atrial fibrillation randomized to either DOAC or warfarin. Dr. Anthony Carnicelli: And, from a method standpoint, we are fortunate at Duke and at DCRI, to have an expert in the network, meta-analysis methodology, whom we've worked with, Dr. Bonnie Huang, who helped to put together the analysis here and to proceed with this kind of network methodology. Dr. Anthony Carnicelli: And so, again, our goal was to evaluate the overall safety and efficacy of DOACs versus warfarin, but then also to dive into some specific subgroups, both from a categorical covariant perspective, and then also to evaluate some continuous covariants, specifically age, and to assess gender across the entire spectrum of continuous age in our population, which, of course is a unique opportunity in the individual patient-level data. Dr. Greg Hundley: And, Anthony, you had, gosh, it looks like over 70,000 patients in this particular analysis. Tell us a little bit about the results. Dr. Anthony Carnicelli: Yeah, so interesting, actually, and I agree that the biggest strength of our meta-analysis is the individual patient-level data and also the profound number of randomized patients included. So I think, from a high level, the most important results to highlight are the fact that there is a 19% relative risk reduction in stroke or systemic embolism among patients who are randomized to DOACs compared to warfarin, with an 8% reduction in all-cause death and a 55% reduction in intracranial hemorrhage. Dr. Anthony Carnicelli: So a massive reduction in the most feared complications of both atrial fibrillation and then also those associated with systemic oral anticoagulation. We also found a trend towards less bleeding in patients randomized to the standard-dose DOAC group, as well. Dr. Greg Hundley: Very good. Well, Chris, we're going to turn to you. What an exciting discovery here, and beautiful methodology. I wonder, in addition to what Anthony has shared with us, were there particular outcomes that were pertinent to men versus women or perhaps related to age? Dr. Christopher Granger: Yeah, Greg. So, again, we're proud of this as being really the state-of-the-art ability to evaluate safety and efficacy in this incredibly important population of patients with Afib and at risk for stroke, and to be able to dive into the subgroups and to the individual outcomes, even the less common outcomes. And one of the most striking things, and this really reinforces prior data, but with the greatest confidence of any study ever done, there was this 55% at reduction in intracranial hemorrhage and 19% reduction in total stroke and systemic embolism, really highlighting that these drugs are clearly better than warfarin, from reinforcing the guidelines. Dr. Christopher Granger: And the message with the subgroups is there was really a remarkable amount of consistency. And specifically in the older population where people are really concerned about anticoagulation, there was a clear and consistent major advantage of DOACs over warfarin. Men versus women, clear, clear, compelling benefit of DOACs over warfarin across each of these outcomes, including mortality, by the way, 8%. But highly statistically significant reduction in total mortality. Dr. Christopher Granger: A couple of the interesting ones, there was some effect modification. In other words, some evidence of an even greater benefit in patients who were not previously on a vitamin K antagonist or who had lower creatinine clearance, really important group, right? The renal impairment group. Dr. Christopher Granger: And then there was a greater benefit of lower risk of bleeding for patients with low body weight. And, in fact, the younger population, if anything, had a greater benefit with respect to less bleeding. And the bleeding is so important, Greg and Shinya, right? Because that's the major reason that people are not using anticoagulation, warfarin or DOACs, for this large population of patients who are untreated. And I hope this meta-analysis will be viewed as evidence that have really safe and effective treatments that are underused for this population that we're concerned about bleeding. Dr. Greg Hundley: Excellent. Thanks so much, Chris. Well, Shinya, you see a lot of papers come across your desk. What attracted you to this particular paper? And then can you help us put these results in the context with others that have evaluated the utility of DOACs in patients with atrial fibrillation? Dr. Shinya Goto: Thank you, Greg. Let me congratulate for Anthony and Chris and also group for conducting this great work. I mean, combine AF with amazing success for sharing the clinical trial database. So that all the four with a DOAC available is approved by each country based upon individual trial. Individual trial itself, large enough, right? Include more than 10,000 patient, but this time the [OSA 00:19:49] accumulated all four DOAC trial database together so that it is easy to say clinical trial data sharing provided robust evidence. Dr. Shinya Goto: But it is difficult, actually, to conduct it. I really commended OSA to conduct this success. So the data is predicted, I would say. Individual clinical trial itself shows lower risk of bleeding in DOAC as compared to warfarin. But this paper really provides the first time standard dose of DOAC reduce the risk of stroke and systemic embolism and death as compared to warfarin. Dr. Shinya Goto: So I really commented OSA. So this paper have a strong impact on the medical care. DOAC rapidly change the standard of care already. But superior efficacy was shown only in a few dose of DOAC, like 150 milligram BID of dabigatran, 60 milligram QD edoxaban, and five milligram apixaban. But this combined AF provides a stronger and a trustable robust evidence DOAC is better than warfarin. Dr. Greg Hundley: Very nice. Well, gentlemen, I want to turn back to you. I'll start with Anthony and then Chris, and then Shinya. Anthony, what do you think is the next study to be performed, really, in this space? Dr. Anthony Carnicelli: Well, it may be a bit of a pitch, but I mean, we have many opportunities in the combined AF data set to perform additional analyses, but I think that one of the most important next steps in this space that I'm most excited about is with respect to the newer oral anticoagulants that are coming down the pike. Dr. Anthony Carnicelli: For example, the Factor 11 inhibitor space. I mean, I think that there is another opportunity in the near future to potentially revolutionize the systemic anticoagulation space. And I think that data from combined AF could potentially be used to help continue moving the ball forward, again in the development of newer agents. So I think that's probably the thing that I'm most excited about in this space. Dr. Greg Hundley: Very good. And, Chris? Dr. Christopher Granger: Greg, I think there's so many unanswered questions and I think, as Tony points out, this highlights the fact that we know a lot, but there's a lot of unanswered questions. And those, some of the ones that I'm most interested in are low burden AFib, this AFib that we're detecting now with smart watches and devices, and what we do with that. And patients with renal impairment, including all the way down to renal failure, where those are relatively underrepresented, including in the combined AF data set. Dr. Greg Hundley: Very good. And, Shinya? Dr. Shinya Goto: Yeah. Yeah, Anthony and Chris talked about a little bit the plans to space, but I insist there is a lot of space that also could do with the combined AF database. We can expect a lot of sub-analysis, like you conducted as a continuous variable in this paper, but you can do that with eGFR as continuous variable, PMI as continuous variable. So we can expect a lot of sub-analysis. Probably, this is the end of publication from the individual DOAC development trial. You change the game with the combined AF data set. Dr. Greg Hundley: Very good. Well, listeners, we want to thank Dr. Anthony Carnicelli, Dr. Christopher Granger and our own associate editor, Dr. Shinya Goto, for bringing us this very interesting result from the meta-analysis that, compared to warfarin, DOACs have a more favorable efficacy and safety profile among patients with atrial fibrillation. Well, on behalf of Carolyn and myself, we 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, 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.

Commentary by Dr. Valentin Fuster

This week's episode features author Kieran Docherty and Associate Editor Torbjørn Omland as they discuss the article "The Effect of Neprilysin Inhibition on Left Ventricular Remodeling in Patients with Asymptomatic Left Ventricular Systolic Dysfunction Late After Myocardial Infarction." 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 at VCU Health in Richmond, Virginia. Well, Carolyn, we've got an exciting feature this week involving Neprilysin license inhibition and left ventricular remodeling in patients with asymptomatic left ventricular systolic function after they've sustained myocardial infarction. But before we get to that feature discussion, how about we grab a cup of coffee and jump in on some of the other articles in the issue? Would you like to go first? Dr. Carolyn Lam: I'd love to, and I want to talk about transcatheter aortic valve replacement, or TAVR, that we all know is really transforming our management of aortic stenosis. Despite rapid improvements, however, serious complications remain relatively common and are not well-described by single outcome measures. So the purpose of this paper was to determine if there was site-level variation in TAVR outcomes in the United States using a novel 30-day composite measure. And this is from Dr. Desai and colleagues from Hospital of University of Pennsylvania. So they performed a retrospective cohort study using data from the STS/ACC TVT registry to develop a novel-ranked competent performance measure that incorporates mortality and serious complications. Based on the associations with one-year risk adjusted mortality and health status, they identified for peri-procedural complications to include in the composite risk model, in addition to mortality. And ranked empirically, according to severity, these were: stroke, major life-threatening or disabling bleeding, stage three acute kidney injury, and moderate or severe perivalvular regurgitation. Dr. Carolyn Lam: Now, based on these ranked outcomes, they found that there was significant site-level variation in quality of care in TAVR in the United States. Overall, better-than-expected site performance was observed in 8% of sites, whereas performance as-expected was observed in 80%, and worse-than-expected performance was observed in 11% of sites. Dr. Greg Hundley: Carolyn, really interesting comprehensive data. So how do we put this all together? And what's the take-home message for us, clinically? Dr. Carolyn Lam: Well, there are substantial variations in the quality of TAVR care received in the United States, and 11% of sites were identified as providing care below the average level of performance. Further study is necessary to determine the structural, process-related, and technical factors associated with high- and low-performing sites. And all this is discussed in a beautifully, beautiful accompanying editorial by Drs. Dharam Kumbhani and Eric Peterson.   Dr. Greg Hundley: Oh, fantastic. You know, Carolyn, those editorials are so helpful in helping us put these new data in perspective. Well, my next paper comes to us from the world of preclinical science, and it's from Professor Vincent Christoffels from Amsterdam in UMC. So genetic variants of SCN10A, encoding the neural voltage-gated sodium channel NaV1.8 are strongly associated with atrial fibrillation, Brugada syndrome, cardiac conduction velocities, and heart rate. And these investigators studied the cardiac expression of SCN10A and the function of a variant-sensitive intronic enhancer previously linked to the regulation of SCN5A, and coding the major essential cardiac sodium channel NaV1.5. Dr. Carolyn Lam: Wow, great. So what did they find, Greg? Sounds like a first-of-its-kind study. Dr. Greg Hundley: Right, Carolyn. So genetic variants in and around SCN10A modulate enhancer function and expression of the cardiac-specific NCN10A short transcript, and the authors propose that non-encoding genetic variation modulates transcriptional regulation of a functional C-terminal portion of NaV .8 and cardiomyocytes that impacts NaV1.5 function, cardiac conduction velocities, and arrhythmia susceptibility. Dr. Carolyn Lam: Wow, that was a lot. So what are the implications, Greg? Could you simplify it for us? Dr. Greg Hundley: Yes. Right, Carolyn. So three things. First, the authors uncovered a novel alternative mechanism for how the SCN10A locus regulates cardiac conduction. Second, their data implicate that genetic variation-sensitive regulation of expression of NCN10A short modulates conductivity of the heart, and can predispose to arrhythmia in the human population. And then finally, Carolyn, in deciphering the underlying mechanism of the increased NaV1.5 mediated current density by NaV1.8 short, the authors believe their findings could ultimately lead to the development of novel therapeutic strategies for particular conduction disorder. Dr. Carolyn Lam: Thanks, Greg. Well, this next paper is really interesting. It's the first validation of the enhanced potency of human-induced pluripotent stem cells-derived cardiomyocytes over-expressing Cyclin D2, or CCND2, under the control of myosin heavy chain promoter, and differentiated into cardiomyocytes. Now, that was a mouthful, but so interesting, because Dr. Zhang and colleagues from University of Alabama in Birmingham used infarcted pig hearts, and transplanted these amazing cardiomyocytes, and found that they were associated with proliferation of recipient heart cardiomyocytes, epithelial cells, and smooth muscle cells, all, at least partly, by paracrine activity. Dr. Greg Hundley: Well, Carolyn. Really an involved clinical design. So, what are the clinical implications of all this research?   Dr. Carolyn Lam: Well, first, I think the paper validated a novel therapeutic strategy aimed at upregulating proliferation of recipient cardiac cells using human-induced pluripotent stem cells-derived cell or cell products. Furthermore, targeting the myocyte cell cycle regulators, such as Cyclin D2, holds a strategic potential for re-muscularization of an infarcted region. Dr. Greg Hundley: Very good, Carolyn. Well, how about we see what else is in this issue? So I'll start first. There's a Research Letter by Professor Marston, entitled 'Combining High-Sensitivity Troponin with the American Heart Association/American College of Cardiology Cholesterol Guidelines to Guide of Avelumab Therapy'. Next, there's an ECG challenge from Dr. Feliciano, entitled 'An Ominous EKG'. And then finally, there's a very nice exchange of letters from Drs. Lang and Sattar regarding a prior publication: volume status is the key in heart failure. Dr. Carolyn Lam: And finally, a very important perspective piece by Dr. Catapano on omega-3 for cardiovascular disease: where do we stand after reduce it in strength? Wow, that was great, Greg. But let's move on now to our feature discussion. Dr. Greg Hundley: You bet. Dr. Greg Hundley: Well, listeners, we are on to our feature discussion today, on this July 20 issue. And we're very excited to have with us Dr. Kieran Docherty from University of Glasgow in Glasgow, Scotland, and our own associate editor, Dr. Torbjørn Omland from University of Oslo in Oslo, Norway. Welcome, gentlemen. And Kieran, let's start with you. Could you describe some of the background related to your study, and what was the hypothesis that you wanted to address? Dr. Kieran Docherty: Well, firstly, thank you very much for the invitation to discuss our trial today on the podcast. The background of our trial was that we are all aware that the development of left ventricular systolic dysfunction following acute myocardial infarction places patients at a subsequent increased risk of the development of heart failure, and the process of progressive dilatation of the left ventricle and a reduction in stroke volume, known as adverse left ventricular remodeling, is the process which underlies this elevated risk of heart failure. And many of the treatments that have been shown to be beneficial following myocardial infarction, such as [inaudible 00:09:24] , and angiotensin receptor blockers and beta blockers, the benefit of these medications, in part, is due to their ability to attenuate this process of adverse remodeling. Now, our hypothesis was that it would be possible to further attenuate, prevent, or delay the process of adverse remodeling in patients at risk of heart failure following myocardial infarction, by the addition of a Neprilysin inhibitor to current standard of care. Dr. Kieran Docherty: Now, as we all know, a Neprilysin inhibitor in the form of sacubitril valsartan when combined with an angiotensin receptor blocker, has been shown to improve outcomes in patients with symptomatic heart failure, with reduced ejection fraction in the PARADIGM-HF trial, and Neprilysin inhibitors increase endogenous levels of natriuretic peptides, amongst a range of other substrates for Neprilysin, including adrenomedullan, GLP-1, and bradykinin. And our hypothesis was that adding in a Neprilysin inhibitor, thereby increasing endogenous levels of these peptides with potentially beneficial effects, such as reducing fibrosis, reducing hypertrophy, [inaudible 00:10:34] and diuresis, may have an additive beneficial effect on left ventricular remodeling in these high-risk patients with left ventricular systolic dysfunction following myocardial infarction. Dr. Greg Hundley: Very nice hypothesis. So, how did you set up, Kieran, your study design, and what study population, how many patients and whatnot, did you include in your study? Dr. Kieran Docherty: Well, the first consideration when designing the study was broadly, what group of patients should we involve? And the main limitation was the indication for the use of sacubitril valsartan in patients with symptomatic heart failure, so we did not feel that we could include these patients. Therefore, our study population included patients who had asymptomatic left ventricular systolic dysfunction following previous myocardial infarction. And specifically, we wanted patients who were at least three months following my cardiac infarction. And the reason for that was to try and exclude patients who had transient systolic dysfunction or left ventricular stunning. And we performed a screening transthoracic echo at this time point. And if patients had an ejection fraction of 40% or less on echo, and if they were tolerant of a minimum dose of an ACE inhibitor, 2.5 milligrams of ramipril BD or equivalent, and they were taking a beta blocker, unless contraindicated or not tolerated, then they were suitable for randomization. Dr. Greg Hundley: Very good. And what did you find? Dr. Kieran Docherty: So we find that in comparison with the ARB Valsartan, sacubitril valsartan did not have any beneficial effects on cardiac MRI-based measures of left ventricular remodeling. And the primary end point of our study was left ventricular end systolic volume index. There was also no improvements in biomarkers of myocardial stress, i.e. NT-proBNP, or my cardio injury, i.e. high sensitivity to Troponin I. Dr. Greg Hundley: Very nice. And any pertinent issues relevant to, perhaps, some subgroups, regardless of age or perhaps gender? Dr. Kieran Docherty: So in a post-hoc analysis, we performed an analysis of the primary endpoint in patients who were below or at or above the median NT-proBNP level, which is 238 p-grams per mil. And we found, very interestingly, the suggestion of a benefit, in terms of left ventricular remodeling with a reduction and systolic volume index in patients who had higher levels of NT-proBNP compared to those who had lower levels. Dr. Greg Hundley: Very good. Well, listeners, let's turn now to our associate editor, Dr. Torbjørn Omland, who... Torbjørn, you see many papers come across your desk. What attracted you to this manuscript? And then how do you put the results of this study in the context with other studies that have been published, particularly recently, in patients with heart failure that have received sacubitril valsartan? Dr. Torbjørn Omland: So, Greg, there were many aspects of this trial that made it very attractive for circulation. I think the hypothesis was very interesting, and also it is a very well-conducted study using the reference methods for assessing left ventricular function, using that for assessing the primary endpoint. And they also have a broad array of secondary end points that also sort of provide insight in potential pathways or mechanisms that can explain the effect sacubitril Valsartan. So, that's also a very sort of hot topic within the cardiology research currently, and we know that the ACC, actually a much larger study, PARADISE-MI, was presented. And we knew that this study was also very interesting, because we knew when we received this manuscript, that another, bigger trial that's sort of related would be presented at the ACC at the late-breaking clinical trial sessions there the PARADISE-MI study. But this sort of provided insight that nicely complimented the results of that study. Dr. Torbjørn Omland: And I think as Kieran alluded to, we already have the very impressive results from PARADIGM-HF is showing a very substantial benefit in patients with chronic heart failure and reduced ejection fraction. And then we have sort of the borderline results from the Paragon trial, in those with preserved ejection fraction, where it actually was a gradient from those with mildly elevated, where there seemed to be a beneficial effect to those with more normal EF, where there was no effect. So, this study sort of provided new information, very relevant to the whole field, I think. Dr. Greg Hundley: Very nice. Well, gentlemen, I want to turn back to you and ask each of you, first Kieran, and then Torbjørn. Kieran, what do you think is the next study that needs to be performed in, really, this sphere of research? Dr. Kieran Docherty: As Torbjørn has already alluded to, PARADISE-MI kind of... It fills the gap across the spectrum of heart failure. So in patients who are at high risk of heart failure immediately following myocardial infarction, that that group of patients were studied in PARADISE-MI. And there is an echocardiographic sub-study of PARADISE-MI, which we await the results for. And I think that will be very interesting, because our patient population was distinct from the group studied in PARADISE-MI, namely the fact that the median time from MI was 3.6 years. So, these patients were not in the throes of the neural humoral activation at the time of acute myocardial infarction and prior to the development of established my cardio scar and fibrosis. And so, it may be that the addition of a Neprilysin inhibitor to patients immediately following myocardial infarction may have some benefits, in terms of attenuating or preventing ventricular dilatation reduction and injection fraction that is observed. So I think we await the echocardiographic results of PARADISE-MI with great interest. Dr. Greg Hundley: Very good. And Torbjørn , do you have anything to add? Dr. Kieran Docherty: Yes. I found observations that actually, in terminal proBNP measurements, could potentially identify a higher-risk group that actually could benefit from the intervention. It was very interesting. So I think we always speak about precision medicine and cardiology, and I think this is sort of one avenue that we should pursue and see whether we use biomarkers like NT-proBNP to identify those patients who will benefit most from interventions like sacubitril Valsartan Dr. Greg Hundley: Excellent. Well, listeners, we've heard a really interesting discussion today. Another study investigating Neprilysin inhibition in combination with angiotensin receptor blockers, and basically highlighting that in patients with asymptomatic left ventricular dysfunction following several years after myocardial infarction, that treatment with sacubitril Valsartan did not have a significant reverse remodeling effect just compared with valsartan alone. Well, on behalf of Carolyn and myself, we want to thank Dr. Kieran Docherty and his submission here to circulation, and also our own associate editor, Dr. Torbjørn Omland. Dr. Greg Hundley: And for all of you, we wish you a great week, and we hope to catch you next week on The Run. Dr. Greg Hundley: This program is copyright of the American Heart Association, 2021. The opinions expressed by speakers in this podcast are their own, and not necessarily those of the editors or of the American Heart Association. For more visit ahajournals.org.  

Paul J. 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, Bruce Wilkoff and associates examine the impact of cardiac implantable electronic device [CIED] infections on mortality, quality of life, healthcare utilization, and cost in the U.S. Healthcare system. They found that the majority CIED infection was associated with increased all-cause mortality, 12-month risk-adjusted hazard ratio 3.41, P < 0.001. An effect that sustained beyond 12 months.   The quality of life was reduced, P = 0.004, and did not normalize for six months. Disruptions in CIED therapy were observed in 36% of infections for a median duration of 184 days. The authors reported that the mean hospital costs were $55,547.   In our next paper, Songwen Chen, Xiaofeng Lu and associates examine the ability to eliminate premature ventricular complexes [PVCs] originating from the proximal left anterior fascicle, safely from the right coronary sinus. The authors mapped the the right coronary sinus and left ventricle in 20 patients with left anterior fascicle PVCs. They found that the earliest activation site with Purkinje potential during both PVC and sinus rhythm was localized at proximal left anterior fascicle in eight patients, the proximal group, or non-proximal left anterior fascicle in 12 groups, the non-proximal group. The Purkinje potentials proceeded PVC-QRS at the earliest activation site in proximal group 32.6 milliseconds was significantly earlier than that in non-proximal group, 28.3 milliseconds P = 0.025. Similar difference in the Purkinje potentials proceeding sinus QRS at the earliest activation site was also observed between proximal and non-proximal group, 35.1 milliseconds versus 25.2 milliseconds, P < 0.001.   In proximal group, the distance between the earliest activation site to the left His-bundle into the right coronary sinus were shorter than that of the non-proximal group 12.3 millimeters versus 19.7, P = 0.002, and 3.9 millimeters versus 15.7 millimeters, P < 0.001, respectively. The authors found no difference in the distance between the right coronary sinus to proximal left anterior fascicle between the two groups. PVCs were successfully eliminated from the right coronary sinus in all proximal group, but at left ventricular earliest activation site for the non-proximal group, the radiofrequency application time, ablation time and procedure time of non-proximal group were longer than that proximal group.   Electrocardiographic analysis showed that when compared to non-proximal group, the PVCs proximal group had a narrower QRS duration, smaller S wave in leads one, V five,and V six; lower R waves in leads one, aVL, aVR, V one, V two, and V four and smaller q wave in leads three and aVF. The QRS duration difference [PVC-QRS and sinus rhythm QRS] < 15 milliseconds predicted the proximal left anterior fascicle origin with high sensitivity and specificity.   In our next paper, Benjamin Steinberg and associates examined the factors that are associated with large improvements in health-related quality of life in patients with atrial fibrillation. The authors assessed factors associated with a one-year increase in quality of life, measured by AFEQT of one standard deviation that is greater and equal to 18 points, three times clinically important difference among patients in the ORBIT-AF one registry. They found that 28% of patients had such a health-related quality improvement compared with patients not showing large health-related quality of life improvement. They were similar age, (median 73 versus 74 years of age), equally likely to be female, (44% versus 48%), but more likely to have newly diagnosed atrial fibrillation [AF] at baseline (18% versus 8%, P = 0.0004) prior antiarrhythmic drug use (52% versus 40%, P = 0.005), baseline antiarrhythmic drug use (34.8% versus 26.8%, P = 0.045), and more likely to undergo AF related procedures during follow-up (AF ablation 6.6% versus 2.0%, cardioversion 12.2% versus 5.9%). In multivariate analysis, a history of alcohol abuse has a ratio 2.4 and increased baseline diastolic blood pressure has a ratio 1.23 per 10 point increase and greater than 65 millimeters of mercury were associated with large improvements in health-related quality of life at one year. Whereas patients with prior stroke, chronic obstructive pulmonary disease and peripheral artery disease were less likely to improve.   In our next paper, Eiichi Watanabe and associates studied safety and resource consumption of exclusive remote follow-up in pacemaker patients for two years. Consecutive pacemaker patients committed to remote pacemaker management were randomized to either remote follow-up or conventional in-office follow-up at twice yearly intervals.   Remote follow-up patients were only seen if indicated by remote monitoring, all returned to hospital after two years. In 1,274 randomized patients (50.4% female, age 77 years), 558 remote follow-up or 550 conventional in office follow-up patients reached either the primary end point or 24 months follow-up. The primary end point, a composite of death, stroke, or cardiovascular events requiring surgery occurred in 10.9% and 11.8% respectively in the two groups (P = 0.0012) for non-inferiority. The median number of in-office follow-ups was 0.5 in the remote follow-up group and 2.01 in the conventional in-office follow-up per patient year (P < 0.001). Only 1.4% of remote follow-ups triggered an unscheduled in-office follow-up, and only 1.5% of scheduled in-office follow-ups were considered actionable.   In our next paper, Sarah Strand and associates use fetal magnetocardiography from the University of Wisconsin biomagnetism laboratory to study 39 fetuses with pathogenic variants in long QT syndrome, LQTS genes. 27 carried the family variant, 11 had de novo variants, and one was indeterminant. De novo variants, especially de novo SCN5A variants were strongly associated with a severe rhythm phenotype and perinatal death. Nine or 82% showed signature LQTS rhythms, six showed torsade de pointes, five were still born, and 9% died in infancy. Those that died exhibited novel fetus rythms, including AV block with 3:1 conduction ratio, QRS alternans in 2:1 AV block, long cycle length, torsade de pointes, and slow monomorphic ventricular tachycardia. Premature ventricular contractions were also strongly associated with torsade de pointes and perinatal death. Fetuses with familiar variants showed a lower incidence of signature LQTS rhythm, six out of 27 or 22%, including torsade de pointes, and 3 out of 27 or 11% all were live born. The authors concluded that the malignancy of de novo LQTS variants was remarkably high and demonstrate that these mutations are a significant cause of stillbirth.   In our next paper, Corina Schram-Serban and associates compare the severity of extensiveness of conduction disorders between obese patients and non-obese patients measured at high resolution scale. They studied 212 patients undergoing cardiac surgery (male:161, mean 63 years of age), who underwent epicardial mapping of the right atrium, Bachmann's bundle, and left atrium during sinus rhythm. Conduction delay [CD] was defined as interelectrode conduction time seven to 11 milliseconds and conduction block [CB] as conduction time ≥ 12 milliseconds. In obese patients, the overall incidence of conduction delay was 3.1% versus 2.6% (P = 0.002), conduction block 1.8% versus 1.2%, and continuous CDCB 2.6% versus 1.9% higher in the obese patients, conduction delay (P = 0.012) and continuous CDCB lines are longer. There were more conduction disorders at Bachman's bundle, and this area has a higher incidence of conduction delay 4.4% versus 3.3% (P = 0.002), conduction block 3.1% versus 1.6% (P < 0.001), continuous conduction block conduction delay 4.6% versus 2.7% and longer conduction delay or conduction delay conduction block lines. Severity of conduction block is also higher, particularly in the Bachmann bundle and pulmonary vein areas. In addition, obese patients have a higher incidence of early de novo postoperative atrial fibrillation. Body mass index and the overall amount of conduction block were independent predictors for the incidents of early postoperative atrial fibrillation.   In our next paper, Ricardo Cardona-Guarache and associates describe five patients with concealed, left-sided nodoventricular in four patients and nodofascicular in one patient accessory pathways. They proved the participation of accessory pathway in tachycardia by delivering His-synchronous premature ventricular complexes that either delayed the subsequent atrial electrogram or terminated the tachycardia, and by observing an increase in ventricular atrial interval coincident with left bundle branch block in two patients. The accessory pathways were not atrioventricular pathways because the septal ventricular atrial interval during tachycardia was less than 70 milliseconds in 3, 1 had spontaneous AV dissociation, and in 1 the atria were dissociated from the circuit with atrial overdrive pacing.   Entrainment from the right ventricle showed ventricular fusion in 4 out of 5 cases. A left-sided origin of accessory pathways was suspected after failed ablation of the right inferior extension of the AV node in 3 cases and by observing VA increase in left bundle branch block in 2 cases. The nodofascicular in 3 of the 4 nodoventricular accessory pathways were successfully ablated from within the proximal coronary sinus guided by recorded potentials at the roof of the coronary sinus, and nodoventricular accessory pathway was ablated via a transseptal approach near the coronary sinus os.   In our next paper, Pierre Qian and associates examined whether an open irrigated microwave catheter ablation can achieve deep myocardial lesions endocardially and epicardially through fat while acutely sparing nearby coronary arteries. Epicardial ablations via subxiphoid access in pigs were performed at 90 to 100 Watts at four minutes at sites near coronary arteries and produced mean lesion depth of 10 millimeters, width 18 millimeters, and length 29 millimeters through median epicardial fat thickness of 1.2 millimeters. Endocardial ablations at 180 Watts achieved depths of 10.7 millimeters, width of 16.6 millimeters, and length of 20 millimeters. Acute coronary occlusion or spasm was not observed at median separation distance of 2.7 millimeters.   In our next paper, Jad Ballout and associates examined 21 consecutive patients with cardiogenic shock and refractory ventricular arrhythmias undergoing bailout ablation due to inability to wean off of mechanical support. Mean age was 61 years, 86% were males, median left ventricular injection fraction 20%, 81% ischemic cardiomyopathy. The type of mechanical support in place prior to the procedure was intra-aortic balloon pump in 14 patients, Impella in 2, ECMO in 2, ECMO and intra-aortic balloon pump in 2, and ECMO and Impella in 1. In the cardio voltage maps with myocardial scar in 90% (19 patients), the clinical ventricular tachycardias VTs were inducible in 13% (62 patients), whereas 6 patients had PVC induced ventricular fibrillation, VT (29%), and VT could not be induced in 2 patients (9%). Activation mapping was possible in all 13 patients with inducible clinical VTs, substrate modification was performed in 15 patients with scar in 79%. After ablation and scar modification, the arrhythmia was noninducible in 19 patients (91%). Seventeen (81%) were eventually weaned off mechanical support successfully with the majority of patients being discharged home and surviving beyond one year. However, 6 (29%) died during the index admission with persistent cardiogenic shock.   In a research letter, Parveen Garg and associates examined the multi-ethnic study of atherosclerosis [MESA] incident atrial fibrillation a population with 50% African-American or Hispanic. After adjusting for age, race, ethnicity, sex education, income, clinic site, height, body, mass index, cigarette, smoking, diabetes, systolic and diastolic blood pressure, and hypertensive medications, physical activity, alcohol consumption, lipid parameter to lipid lowering therapy, the baseline lipoprotein A level greater or equal to 30 milligram per deciliter was inversely associated with developing atrial fibrillation compared those with lower levels (hazard ratio 0.84). However, the mechanism of this paradoxical association is unclear.   In another research letter, Yoshihide Takahashi and associates reported that 49 patients undergoing ablation of persistent atrial fibrillation had at least one focal site and rotational activation in 57%. Of these, 19 patients underwent a repeat ablation for recurrent atrial fibrillation. AF was mapped in 17 patients and 131 focal activation sites were ablated. There were 105 displayed focal activation sites during the de novo ablation and 89 focal activation sites during the repeat ablation. During the de novo ablation, rotation activation was observed in 19 sites. Of the 19 sites, 12 (63%) displayed rotational activity, also with the repeat ablation. The author suggested focal or rotational activation sites can be classified into two types, ones critical for AF recurrence and the ones that are bystander.   That's it for this month. We 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, 2020.   Correction: In the study by Pierre Qian and associates, the epicardial ablations via subxiphoid access were performed in sheep, not pigs, as previously stated.

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Mark Mercola, PhD Stanford University Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 36334]

Dr Carolyn Lam: Well, the 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 Centre and Duke National University of Singapore. Dr Greg Hundley: And I'm Dr Greg Hundley, associate editor from the Pauley Heart Center at VCU Health in Richmond, Virginia. Well, Carolyn, this week's feature involves the Compass trial, and we'll be talking about a comparison of low-dose rivaroxaban plus aspirin compared to aspirin alone in patients with chronic vascular disease. But before we get to that, how about if we break away and discuss a few other papers. And I'll go first this time, because this week we're going to introduce another new feature in addition to Carolyn's Quiz. Dr Carolyn Lam: Wait a minute. This was not on the script. What's going on, Greg? Dr Greg Hundley: It's on the script! Carolyn, let me get to my first paper. It's from Professor Junling Liu from Shanghai Jiao Tong University School of Medicine, and it involves branched-chain amino acid catabolism and how that may promote thrombosis risk by enhancing tropomodulin-3 propionylation in platelets. But first, we've got a new feature to add to Carolyn's Quiz. It's called Way or No Way. Dr Carolyn Lam: Just so everybody knows. This was a one-way decision to add this new component of Carolyn's Quiz, but okay, I'm all for it. Go, Greg! Dr Greg Hundley: Okay. All right. It's a fast, quick question where our listeners seek your guidance regarding an important scientific discovery from one of our published manuscripts. Are you ready? Dr Carolyn Lam: No. Dr Greg Hundley: Okay. Here's your question. Do branched-chain amino acids promote arterial thrombosis. Way or no way? Dr Carolyn Lam: Maybe? Dr Greg Hundley: Okay, Carolyn. Dr Carolyn Lam: I have a feeling you're going to tell us yes, although I wouldn't have guessed that straight away. Dr Greg Hundley: Okay. Remember that branched-chain amino acids are essential nutrients, including leucine, isoleucine, and valine, and they serve as a resource for energy production and the regulator of important nutrient and metabolic signals. In this study, the activity of human platelets from healthy subjects before and after ingestion of branched-chain amino acids were measured. PP2Cm-deficient mice were used to elucidate the impacts of BCAA catabolism on platelet activation and thrombus formation. Dr Carolyn Lam: Now okay, okay. So what did they find? Way or no way? Dr Greg Hundley: Ingestion of branched-chain amino acids significantly enhanced the activity of platelets in response to agonists and increased the risk of arterial thrombosis. The branched-chain amino acid catabolic pathway-driven propionylation of tropomodulin-3 at K255 was found to be an important mechanism underlying the branched-chain amino acid-facilitated platelet activation, and elevated levels of branched-chain amino acids and enhanced expression of positive regulators of branched-chain amino acid catabolism in platelets were found probably responsible for the high platelet activity in type 2 diabetes mellitus. Dr Carolyn Lam: Very interesting. So yes, it is possible. And what is the clinical implications? Dr Greg Hundley: Right, Carolyn. Branched-chain amino acids, or their catabolites, enhance the risk of arterial thrombosis in small animals, and perhaps future human subject studies, that restrict branched-chain amino acid intake or target branched-chain amino acid catabolism may serve as a novel strategy for anti-thrombosis therapy. Dr Carolyn Lam: Interesting. Okay, Greg. Here you go. Question for me. Have you heard of Home Time?   Dr Greg Hundley: Home Time? Yes. Home Time. It's not like time out for our kids, but we've been having a lot of Home Time in this COVID-19 with our families. Dr Carolyn Lam: All right. Touché. Touché. Home Time! Did you know it is a patient-centered outcome measure that accounts for rehospitalization mortality and post-discharge care? In the paper I want to talk about, Dr Pandey from UT Southwestern and colleagues aim to characterize risk-adjusted 30-day Home Time in patients with acute myocardial infarction as a hospital-level performance metric, and to evaluate associations with risk-standardized readmission rates. The study included almost 985,000 patients with AMI hospitalization across almost 2,400 hospitals between 2009 and 2015 derived from a hundred percent of Medicare claims data. And they found that 30-day home time for patients with AMI can be assessed as a hospital-level performance metric using Medicare claims data. It varied across hospitals, was associated with post-discharge readmission and mortality outcomes, and meaningfully reclassified hospital performance compared with the 30-day readmission and mortality metric. Dr Greg Hundley: Very nice, Carolyn. Well, I'm coming back at you again with another quiz. But first, this paper is from Kamal Khabbaz from Beth Israel Deaconess Medical Center and the Harvard Medical School, and it's going to assess whether left atrial appendage closure or exclusion during bypass surgery has impact on short-term outcomes. So, Carolyn, here's your quiz. Do you think that patients receiving CABG with atrial fibrillation should undergo ligation of their left atrial appendage? Dr Carolyn Lam: Well, I think there's definitely equipoise there. On the one hand, you're already in a surgery. Why not just ligate it? It's not like we need a left atrial appendage. And then on the other hand, I suppose it extends the surgery, it involves some risk, and we don't know if it actually prevents further events. Did I answer that right? Dr Greg Hundley: Yes. Quite the politically correct answer, I think. Now, the objective of this study was to evaluate the impact of left atrial appendage exclusion on short-term outcomes in patients with atrial fibrillation undergoing isolated coronary artery bypass graft surgery. The study analyzed 250,287 CABG patients, of whom 7% received left atrial appendage closure. Only patients with a history of atrial fibrillation were included in the analysis, and the primary outcome was 30-day readmissions following discharge. Secondary outcomes included hospital mortality and stroke. And to assess the postoperative outcomes, the team utilized multivariable logistic regression models, and they adjusted for clinical and demographic co-variables. Dr Carolyn Lam: Great. So what did they find, Greg? Dr Greg Hundley: Okay. Couple of conclusions. First, left atrial appendage exclusion was associated with a greater risk of postoperative respiratory failure, acute kidney injury, but it did not significantly change the rate of blood transfusions or the occurrence of cardiac tamponade. Second, left atrial appendage exclusion was associated with a nonsignificant reduction in stroke, no difference in in-hospital mortality, and a greater risk of 30-day readmissions. Number three, after adjusting for these co-variables, left atrial appendage ligation remained a significant predictor of this 30-day readmissions. And so, Carolyn, in this study, it looks like left atrial appendage exclusion during isolated CABG in patients with AFib is associated with a higher rate of 30-day readmissions. Dr Carolyn Lam: Thanks, Greg. Well, let me talk about what else is in this issue. First is a pair of letters, one from Kai Wu regarding the article, "Effects of Sacubitril-Valsartan Versus Valsartan in Women Compared to Men With HFpEF: Insights From PARAGON-HF" and the response from Dr John McMurry. There are also two On My Mind pieces, one entitled "COVID-19 Arrhythmic Risk and Inflammation: Mind the Gap" by Dr Lazzerini, and another entitled, "Obesity, A Risk Factor for Severe COVID-19 Infection: Multiple Potential Mechanisms" by Dr Naveed Sattar. There are two perspective pieces, "Establishment and Management of Mechanical Circulatory Support During COVID-19 Pandemic" by Dr Pham, and "The COVID-19 Pandemic: A Global Natural Experiment" by Dr Blake Thomson. There's an in-depth paper entitled "The Science Underlying COVID-19: Implications for the Cardiovascular System" by Dr Peter Liu. This is important. This one's an editor's pick, so don't forget to read this. There's an ECG challenge by Dr Praveen Gupta on "Chest Pain with ST Elevation: Looking Behind the Masquerade." In Cardiology News by Tracy Hampton, she reviews the literature and highlights three papers, one, "A Cardiovascular Disease-Linked Gut Microbial Metabolite Acts via Adrenergic Receptors" in Cell 2020; two, "Noninvasive Localization of Cardiac Arrhythmias Using Electromechanical Wave Imaging" in Science and Translational Medicine 2020; and three, "Somatic Gene Editing Ameliorates Skeletal and Cardiac Muscle Failure in Pig and Human Models of Duchenne Muscular Dystrophy", and that in Nature Medicine 2020. For the President's Page, we have a piece by Keith Churchill, who's the Executive Vice President and CEO of Yale New Haven Hospital entitled "The Compelling Need to Address Uncertainty, Anxiety, and Financial Peril for Patients". There's Highlights from Circulation Family of Journals by Sara O'Brien, including "Factors Associated With Large Improvements in Health-Related Quality of Life in Patients with Atrial Fibrillation: Results From the ORBIT-AF" from Circulation Arrhythmia and Electrophysiology. There's "Association Between Sleep Disordered Breathing and Left Ventricular Function: A Cross-Sectional Analysis of the ECHO-SOL Ancillary Study" from Circulation Cardiovascular Imaging. There's also "The Impact of a 10 Rules Protocol on COVID-19 Hospital-Related Transmission: Insights from Padua University Hospital in Italy" from Circulation Cardiovascular Interventions. There's "The Association of an AMI Readmission-Reduction Program with Mortality and Readmission" from Circulation Cardiovascular Qualities and Outcomes. And finally, "Treatment Differences in Chronic Heart Failure Patients with Reduced Ejection Fraction According to Blood Pressure" in Check HF, and that's in Circulation Heart Failure. Dr Greg Hundley: Very nice, Carolyn. Well, I've got just a few Research Letters that I reviewed. First is from Professor Puck Peltenburg, and the Research Letter involves children and adolescents from Brugada syndrome families in which only the SCN5A mutation carriers develop a type one ECG pattern induced by fever. And the second research letter is from Dr David Saadoun, and this evaluates the long-term outcome and prognosis factors associated with isolated aortitis. And then finally, Carolyn, there's a very nice piece related to the current status of cardiovascular medicine in Israel from Professor Ran Kornowski at the Rabin Medical Center. Well, Carolyn, what a packed issue we have, and how about now we get on to that feature discussion? Dr Carolyn Lam: Let's go, Greg. Dr Greg Hundley: Well, listeners, we have a wonderful feature discussion for you in this next segment. We have Professor Keith Fox from Edinburgh and our own associate editor, Professor Stefan James from Uppsala. And we're going to discuss anticoagulation and antiplatelet therapy and rivaroxaban and aspirin and results from the COMPASS trial. Keith, could you tell us what was the background information and what was the hypothesis that you wanted to test with your study? Professor Keith Fox: The hypothesis was whether the combination of a very small dose, a quarter of the dose tested here, of a NOAC alongside an antiplatelet would be superior to aspirin alone, or we also tested a half dose of the NOAC by itself. And the overall trial showed that the quarter dose of rivaroxaban plus aspirin was substantially superior to aspirin alone in preventing cardiovascular death, MI, and stroke, with its biggest impact on strokes and cardiovascular death. So that's the trial as a whole. But our specific goal here was to look at the question of net clinical benefit because clinicians are challenged by any therapy that has a balance of both potential hazard, like bleeding risk, and benefit. So what we analyzed here were the pre-specified characteristics of net clinical benefit in terms of life-threatening and major bleeding into a critical organ, plus cardiovascular death, MI, and stroke. And I asked the question, what was the net clinical benefit? Dr Greg Hundley: Net clinical benefit. Now, tell us a little bit about what population you were looking to understand net clinical benefit, and then what was the study design? Professor Keith Fox: This is the whole of the COMPASS trial without the arm that tested rivaroxaban alone, because that did not show significant benefit. So this is the remaining 18,000 patients, double-blind randomized trial. And the trial, as a whole, was stopped early on the recommendation of the DSMB because it met the criteria for benefit by four standard deviations. Now, what's unusual about this is the population of our patients and vascular risk. So these are people who in the past would just be treated with aspirin. So they're not post-MI. They are people with chronic vascular disease, either peripheral or coronary. And in the past, on top of standard secondary prevention care, they would only have got aspirin. Dr Greg Hundley: And what were the results? Professor Keith Fox: There was a 20% reduction in terms of the net clinical benefit favoring the combination of rivaroxaban and aspirin, and that net clinical benefit being the combined impact of cardiovascular death, MI, stroke, fatal bleeding, or bleeding into a critical organ. Dr Greg Hundley: And did you find the same results in, for example, older versus some of the younger patients? Or were there any other high-risk subgroups, those with impaired renal function or those with heart failure where you saw particular differences? Professor Keith Fox: Yes, Greg. This is a really important issue. If one looked at the whole trial, the number needed to treat to prevent one of these adverse events, N equals 52. But then if we looked at some of the higher-risk cohorts, which we defined prospectively ... For example, these were the risk factors like polyvascular disease, impaired renal function, ambulant heart failure, or diabetes. And if you had all four risk factors, the number needed to treat was nine. If you had three risk factors, it was 12. Two risk factors, 31. So I think there's clearly a message for clinicians to be able to identify people with a combination of these risk factors, one or more, in order to get the most benefit and the least hazard. Dr Greg Hundley: Very interesting. Any speculation on mechanism? Professor Keith Fox: Yes. One of the things that we've done in the past is we've hammered one antithrombotic pathway. Like, for example, we've used more and more potent anti-platelets or combination of anti-platelets. But perhaps one of the things that we've forgotten is the fact that the platelet activation pathway is triggered by thrombin activation and vice versa. So the concept that was new behind the whole COMPASS study was that augmentation of the antithrombotic effects by combining a very small dose of a novel anticoagulant would be beneficial. And the critical question is, would it be sufficiently beneficial without producing a lot of bleeding? So that's why we did this particular analysis. Dr Greg Hundley: So lower doses of some of these drugs. Well, Stefan, can you help us put these study results into context with what we know today about using aspirin alone, rivaroxaban, et cetera? Professor Stefan James: The reason I think this study's so important and interesting is that, first, it's a very common population that we see now in the practice, patients with a stable phase of atherosclerotic disease, both coronary and peripheral vascular. And we need to take care of these patients better. Until now, we have not had very great alternatives for these patients. Now, we've learned what Keith said, that if you combine a low dose of both anti-platelet and antithrombin, you can inhibit and reduce the risk of ischemic events. And the other important finding here is that, I think conceptually very interesting, that if you are able to reduce their number of ischemic complications or thrombotic complications, but not doing that to such an extent that bleeding increases too much, not to an extent that bleeding causes fatal events, then you can find a nice balance between safety and efficacy that can lead to substantial reductions and improvements in terms of the clinical benefit. And that's what we see here in this trial. You can see that there is a reduction of thrombotic events, ischemic events, and there is also some bleeding, but not to such an extent that it affects overall survival and the overall event rate in these patients. And particularly in patients at high risk that you pointed out, these patients have a very high event rate. Although the relative benefit is similar, the absolute benefit is quite impressive. Dr Greg Hundley: Just very exciting to me. Very low doses of some of these common drugs. What's the next study in this field, Keith? Professor Keith Fox: We've got a big gap because we know that modern dual antiplatelet therapy works really well after an acute coronary syndrome and it's highly effective. In the longer term, we know, for example, from some of the studies with ticagrelor that there are cohorts that do well for a period of time after ACS, but really we don't know the bridge between this period and the long term and what role this therapy may have after essential dual antiplatelet therapy. Dr Greg Hundley: Stefan, do you have any thoughts? Professor Stefan James: I agree with Keith. This transition period, when is patient transitioned from being an acute coronary syndrome patient to a chronic coronary syndrome patient? When does that happen? And then probably it differs between individuals and type of events, and so we need to understand more of when is this patient acutely affected and when do we need potent dual antiplatelet therapy? And when can we transition to a more stable phase in which we can inhibit thrombotic events, ischemic events, but not increased bleeding to such a degree that it affects overall survival? And so I think we need to learn a lot more about that transition period and these subgroups of patients of different risks and risks of ischemic events and bleeding events. Dr Greg Hundley: Keith, how would you go about conducting a study in that regard? Professor Keith Fox: I think really one of the very interesting questions is whether the combination of the standard of care of, for example, aspirin and ticagrelor may be better, worse, or the same than this therapy instituted at the end of the period of essential dual antiplatelet therapy. And we need to know that. Dr Greg Hundley: In closing and summing up, Keith, are there any concepts that we want to take home here? Professor Keith Fox: I think that there are two key concepts. One is the synergy between the anticoagulation system and the antiplatelet system, with the potential to use very low doses, to minimize bleeding risk, yet have the benefits. That is the first concept. The second concept is that these chronic vascular disease patients Stefan has described are at continuing risk of vascular events, especially stroke, myocardial infarction, and cardiovascular death. And these can be modified. Dr Greg Hundley: And Stefan, any thoughts from you in closing? Professor Stefan James: I think this paper and the work that Keith has described is fantastic and fascinating to think about because these populations are incredibly large, and they are not doing well. They have a high risk of events, and we tend to forget that, and so we need to both identify them and start treating them now, as we have some evidence, but we'll also need to learn more of how to identify them, how to select them appropriately, and how to identify the transition from acute events to chronic events or current chronic phase of the disease. Dr Greg Hundley: Well, listeners, I want to thank both Professor Keith Fox and our own associate editor, Professor Stefan James, for this very interesting presentation of lower doses of anticoagulant and antiplatelet therapy in patients with chronic vascular disease and really being able to reduce events and diminish bleeding. On behalf of Carolyn and myself, we want to wish you a great week and look forward to catching you next week. Take care. This program is copyright of the American Heart Association 2020.  

Jane Ferguson:                  Hi there. Welcome to Getting Personal: Omics of the Heart, the podcast from Circulation: Genomic and Precision Medicine. I'm Jane Ferguson, and this is Episode 36 from February 2020.                                                 First up, we have “Identification of Circulating Proteins Associated with Blood Pressure Using Mendelian Randomization” from Sébastien Thériault, Guillaume Paré, and colleagues from McMaster University in Ontario. They set out to assess whether they could identify protein biomarkers of hypertension using a Mendelian randomization approach. They analyzed data from a genome-wide association study of 227 biomarkers which were profiled on a custom Luminex-based platform in over 4,000 diabetic or prediabetic participants of the origin trial.                                                 They constructed genetic predictors of each protein and then used these as instruments for Mendelian randomization. They obtained systolic and diastolic blood pressure measurements in almost 70,000 individuals, in addition to mean arterial pressure and pulse pressure in over 74,000 individuals, all European ancestry with GWAS data, as part of the International Consortium for Blood Pressure.                                                 Out of the 227 biomarkers tested, six of them were significantly associated with blood pressure traits by Mendelian randomization after correction for multiple testing. These included known biomarkers such as NT-proBNP, but also novel associations including urokinase-type plasminogen activator, adrenomedullin, interleukin-16, cellular fibronectin and insulin-like growth factor binding protein-3. They validated all of the associations apart from IL-16 in over 300,000 participants in UK Biobank. They probed associations with other cardiovascular risk markers and found that NT-proBNP associated with large artery atherosclerotic stroke, IGFBP3 associated with diabetes, and CFN associated with body mass index.                                                 This study identified novel biomarkers of blood pressure, which may be causal in hypertension. Further study of the underlying mechanisms is required to understand whether these could be useful therapeutic targets in hypertensive disease.                                                 The next paper comes from Sony Tuteja, Dan Rader, Jay Giri and colleagues from the University of Pennsylvania and it's entitled, “Prospective CYP2C19 Genotyping to Guide Antiplatelet Therapy Following Percutaneous Coronary Intervention: A Pragmatic Randomized Clinical Trial”.                                                 They designed a pharmacode genomic trial to assess effects of CYP2C19 genotyping on antiplatelet therapy following PCI. Because loss of function alleles in CYP2C19 impair the effectiveness of clopidogrel, the team were interested in understanding whether knowledge of genotype status would affect prescribing in a clinical setting. They randomized 504 participants to genotype guided or usual care groups and assessed the rate of prasugrel or ticagrelor prescribing in place of clopidogrel within each arm. As a secondary outcome, they assessed whether prescribers adhere to genotype guided recommendations. Of genotyped individuals, 28% carried loss of function alleles. Within the genotype guided group overall, there was higher use of prasugrel or ticagrelor with these being prescribed to 30% of patients compared with only 21% in the usual care group. Within genotype individuals carrying loss of function alleles, 53% were started on prasugrel or ticagrelor, demonstrating some adherence to genotype guided recommendations.                                                 However, this also meant that 47% of people whose genotype suggested reduced effectiveness were nevertheless prescribed clopidogrel. This study highlights that even when genotype information is available, interventional cardiologists consider clinical factors such as disease presentation and may weight these more highly than genotype information when selecting antiplatelet therapy following PCI.                                                 The next paper is about “Deep Mutational Scan of an SCN5A Voltage Sensor and comes to us from Andrew Glazer, Dan Roden and colleagues from Vanderbilt University Medical Center. In this paper, the team aim to characterize the functional consequences of variants and the S4 voltage sensor of domain IV and the SCN5A gene using a high throughput method that they developed. SCN5A encodes the major voltage gated sodium channel in the heart and variants in SCN5A can cause multiple distinct genetic arrhythmia syndromes, including Brugada syndrome, long QT syndrome, atrial fibrillation, and dilated cardiomyopathy, and have been linked to sudden cardiac death.                                                 Because of this, there's considerable interest in understanding the functional and clinical consequences of different variants, but previous approaches were time consuming and results were often inconclusive with many variants being classified as uncertain significance. This newly developed deep mutational scanning approach allows for simultaneous assessment of the function of thousands of variants, making it much more efficient than low throughput patch clamping. The team assessed the function of 248 variants using a triple drug assay in HEK293T cells expressing each variant and they identified 40 putative gain of function and 33 putative loss of function variants. They successfully validated eight of nine of these by patch clamping data. Their study highlights the effectiveness of this deep mutational scanning approach for investigating variants in the cardiac sodium channel SCN5A gene and suggests that this may also be an effective approach for investigating putative disease variants and other ion channels.                                                 The next article is a research letter from Connor Emdin, Amit Khera, and colleagues from Mass General Hospital in the Broad Institute entitled, “Genome-Wide Polygenic Score and Cardiovascular Outcomes with Evacetrapib in Patients with High-Risk Vascular Disease: A Nested Case-Control Study”. In this study, the team set out to probe the utility of using polygenic risk scores to predict the risk of major adverse cardiovascular events within individuals already known to be at high cardiovascular risk and to assess whether genetic scores can identify individuals who would benefit from the use of a CETP inhibitor such as Evacetrapib. They analyze data from the ACCELERATE trial which had tested Evacetrapib in a high risk population, and they found no effect on the incidents of major adverse cardiovascular events overall. Within a nested case-control sample of individuals experiencing major CVD events versus no events, they applied a polygenic risk score and found that the score predicted major cardiovascular events.                                                 Patients in the highest quintile of the risk score were at 60% higher risk of a major cardiovascular event than patients in the lowest quintile. There was no evidence of any interaction between the genetic risk score and Evacetrapib. These data suggest that genetic risk scores may have utility in identifying individuals at high risk events but may not have utility in identifying individuals who may derive more benefit from CETP inhibition. The next letter concerns “Epigenome-Wide Association Study Identifies a Novel DNA Methylation in Patients with Severe Aortic Valve Stenosis” and comes from Takahito Nasu, Mamoru Satoh, Makoto Sasaki and colleagues from Iwate Medical University in Japan. They were interested in understanding whether differences in DNA methylation could underlie the risk of aortic valve stenosis. They conducted an EWAS or epigenome-wide association study of peripheral blood mononuclear cells or PBMCs from 44 individuals with aortic stenosis and 44 disease free controls.                                                 They collected samples at baseline before a surgical intervention in the individuals with aortic stenosis and collected a follow-up sample one year later. They found that DNA methylation at a site on chromosome eight mapping to the TRIB1, or tribbles homolog one gene, was lower in the aortic stenosis group than in the controls at baseline. They replicated the association in an independent sample of 50 cases and 50 controls. TRIB1 MRNA levels were higher in the aortic stenosis group than the controls. When they looked at methylation status one year after aortic valve replacement or a transcatheter aortic valve implantation in patients with stenosis, they found that DNA methylation had increased in the cases while TRIB1 MRNA decreased. These data suggests that methylation status of TRIB1 and expression of TRIB1 may relate to the disease processes in aortic stenosis such as hemodynamic dysregulation and they can be reversed through surgical intervention. Changes in the methylation status of TRIB1 could be a novel biomarker of response to aortic valve replacement.                                                 The next letter comes from Niels Grote Beverborg, Pim van der Harst, and colleagues from University Medical Center Groningen and is entitled, “Genetically Determined High Levels of Iron Parameters Are Protective for Coronary Artery Disease”. Their study addresses the conflicting hypotheses that high iron status is either deleterious or protective against cardiovascular disease. The team constructed genetic predictors of serum iron status using 11 previously identified snips and tested the genetic association with CAD in UK Biobank data from over 408,000 white participants. Overall, the genetic score for higher iron status was associated with protection against CAD. Ten of the snips suggested individual neutral or protective effects of higher iron status on CAD, while one iron increasing snip was associated with increased risk of disease but this was thought to be likely through an iron independent mechanism. Overall, these data suggest that a genetic predisposition to higher iron status does not increase risk of CAD and is actually protective against disease.                                                 The final letter is entitled, “Confidence Weighting for Robust Automated Measurements of Popliteal Vessel Wall MRI” and comes from Daniel Hippe, Jenq-Neng Hwang, and colleagues from the University of Washington. They were interested in assessing whether images of popliteal artery wall incidentally obtained during knee MRI as part of an osteoarthritis study could be used to study the development and progression of atherosclerosis. They developed an automated deep learning based algorithm to segment and quantify the popliteal artery wall in images obtained over 10 years in over 4,700 individuals. Their approach, which they named FRAPPE, or fully automated and robust analysis technique for popliteal artery evaluation, was able to reduce the average time required for segmentation analysis from four hours to eight minutes per image. They applied weights based on confidence for each segment to automatically improve the accuracy of aggregate measurements such as mean wall thickness or mean lumen area. Their data suggest that this automated method can rapidly generate useful information on atherosclerosis from MRI images obtained as part of other studies. When combined with other data. This approach may facilitate novel discovery in secondary analyses of existing studies in an efficient and cost effective way.                                                 And that's all for issue one of 2020. Come back next time for more of the latest papers from Circulation: Genomic and Precision Medicine. Speaker 2:                           This podcast is copyright American Heart Association 2020.  

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. Dr Greg Hundley: And I'm Dr Greg Hundley, associate editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Well, Carolyn, our feature article this week relates to an international multi-center evidence-based reappraisal of genes reported to cause congenital long QT syndrome. But, before we get to that, how about if we grab a cup of coffee and start on our other papers? Do you have one you'd like to discuss? Dr Carolyn Lam: Yes. My favorite part of the week. So this first paper really asks the question, "What's the association between HDL functional characteristics, as opposed to HDL cholesterol levels, and acute coronary syndrome?" The paper comes from Dr Hernáez from IDIBAPS in Barcelona, Spain and colleagues who conducted a case control study nested within the PREDIMED cohort. Originally a randomized trial where participants followed a Mediterranean or low-fat diet. Cases of incident acute coronary syndrome were individually matched one is to two to controls by sex, age, intervention group, body mass index, and follow-up time. The authors measure it the following functional characteristics, which were HDL cholesterol concentration, cholesterol efflux capacity, antioxidant ability, phospholipase A2 activity and sphingosine-1-phosphate, apolipoproteins A1 and A4, serum amyloid A and complement 3 protein. Dr Greg Hundley: Wow Carolyn, a detailed analysis. What did they find? Dr Carolyn Lam: They found that low values of cholesterol efflux capacity, and levels of sphingosine-1-phosphate and apolipoprotein A1 in HDL or all associated with a higher risk of acute coronary syndrome in high cardiovascular risk individuals, irrespective of HDL cholesterol levels and other cardiovascular risk factors. Low cholesterol efflux capacity values and sphingo-1-phosphate levels were particularly associated with an increased risk of myocardial infarction, whereas HDL antioxidant or anti-inflammatory capacity was inversely related to unstable angina. Now this is significant because it's the first longitudinal study to comprehensively examine the association of several HDL function related biomarkers with incident acute coronary syndrome beyond HDL cholesterol levels in a high-risk cardiovascular risk population. Greg Hundley: Very nice. Carolyn. It sounds like function over just the levels is important. Dr Carolyn Lam: Exactly, you summarized it well. Well Greg, I've got another paper and I want to pick your brain first. Is it your impression that type 2 myocardial infarction, the type that occurs due to acute imbalance in myocardial oxygen supply versus demand in the absence of atherothrombosis, do you think that this type of MI is on the rise? It seems more and more common in my country. Dr Greg Hundley: Do we want to say it's on the rise? Certainly by measuring all these high sensitivity troponins, et cetera, we're finding, I think, more evidence of type 2 MI. So, all in all, yeah it probably is on the rise, but likely related to some of our measurement techniques. Dr Carolyn Lam: Oh, you are so smart, Greg. Because this paper that I'm about to tell you about really addresses some of these issues and it's from corresponding author Dr Gulati from Mayo Clinic in Rochester, Minnesota. And they really start by acknowledging that despite being frequently encountered in clinical practice, the population base incidents and trends of type 2 myocardial infarction is unknown and long-term outcomes are incompletely characterized. So they prospectively recruited 5,640 residents of Olmsted County, Minnesota who experienced an event associated with cardiac troponin T greater than 99th percentile of a normal reference population, which is greater than or equal to 0.01 nanograms per milliliter. And this was between 2003 and 2012, so very careful to talk about which Troponin T assay exactly to the point you discussed earlier, Greg. The events were retrospectively classified into type 1 versus type 2 MI using the universal definition. Dr Greg Hundley: So Carolyn, what did they find? Dr Carolyn Lam: They found that there was an evolution in the types of MI occurring in the community over a decade with the incidence of type 2 MI now being similar to type 1 MI. Adjusted long-term mortality following type 2 MI is markedly higher than after type 1 MI and that's driven by early and non-cardiovascular deaths. Mortality of type 2 MI is associated with a provoking factor and is more favorable when the principle provoking mechanism was an arrhythmia compared with postoperative status, hypotension, anemia or hypoxia. And these findings really underscore the healthcare burden of type 2 MI and provide benchmarks for clinical trial design. Dr Greg Hundley: Very nice, Carolyn. Well, my paper comes from type 5 long QT syndromes and an analysis. And it's from Dr Jason Roberts from Western University. Through an international, multi-center collaboration, improved understanding of the clinical phenotype and genetic features associated with rare KCNE1 variants implicated in long QT 5 was sought across 22 genetic arrhythmia clinics and four registries from nine countries that included 229 subjects with autosomal dominant long QT five. So there were 229 of those subjects. And then 19 individuals with the recessive type 2 Jervell and Lang-Nielsen syndrome. The authors compared the effects of clinical and genetic predictors on a composite primary outcome of definite arrhythmic events, including appropriate implantable cardioverter defibrillators shocks, aborted cardiac arrest, and sudden cardiac death. Dr Carolyn Lam: Wow. What did they find? Dr Greg Hundley: Well, several things, Carolyn. First, rare loss of function KCNE1 variants are weakly penetrant and do not manifest with a long QT syndrome phenotype in a majority of individuals. That's a little bit of a surprise. Second, QT prolongation and arrhythmic risk associated with type 2 Jervell and Lang-Nielsen syndrome is mild in comparison with the more malignant phenotype observed for type 1 Jervell and Lang-Nielsen syndrome. And then number three, all individuals possessing a rare loss of function KCNE1 variant should be counseled to avoid QT prolonging medications and should undergo a meticulous clinical evaluation to screen for long QTS phenotype. And then finally, Carolyn, the last finding, in the absence of a long QTS phenotype, more intensive measures, such as beta blockade and exercise restriction, may not be merited. Dr Carolyn Lam: Oh, very interesting. Well, I've got one more original paper and in this, authors describe a new cellular mechanism linking ischemia-reperfusion injury to the development of donor specific antibody, a pathologic feature of chronic antibody-mediated rejection, which mediates late graph loss. This paper is from corresponding author Dr Jane Witt from Yale University School of Medicine and colleagues who use humanized models and patient specimens to show that ischemia-reperfusion injury promoted elaboration of interleukin 18 from endothelial cells to selectively expand alloreactive interleukin 18 receptor 1 positive T peripheral helper cells in allograph tissues and this promoted donor specific antibody formation. Dr Greg Hundley: Carolyn, here's the famous question. What does that mean clinically for us? Dr Carolyn Lam: Aha, I'm prepared. Therapies targeted against endothelial cell derived factors like interleukin 18 may therefore block late complications of ischemia-reperfusion injury. Dr Greg Hundley: Very nice. Sounds like more research to come. Well, how about other articles in the issue? Dr Carolyn Lam: Well, I'd love to talk about a white paper from Dr Al-Khatib, and it's about the research needs and priorities for catheter ablation of atrial fibrillation and this is a report from the National Heart, Lung, and Blood Institute Virtual Workshop. Dr Greg Hundley: Well, I've got another arrhythmia paper, so this is from Professor Michael Ackerman at the Mayo Clinic and its minor long QT gene disease associations by coupling the genome aggregation database. It's a harmonized database of 140,000 or more exomes and genome derived in part from population-based sequencing projects, with phenotypic insights gleaned from a large long QT syndrome registry to reassess the strength of these minor long QT syndrome gene disease associations. Next, Carolyn, in an on my mind piece, Professor Gerd Heusch from University of Essen Medical School discusses, how can the many positive preclinical and clinical proof of concept studies on reduced infarct size by ischemic conditioning interventions and cardioprotective drugs be reconciled with the mostly neutral results in regard to clinical outcomes. The author discusses the important differences between animal models that have been used a lot in this ischemia reperfusion and infarct size reduction science, and then the clinical scenarios of STEMI in humans as well as the many aspects of coronary reperfusion. How is that affecting the myocytes? How is that affecting the microcirculation, et cetera, that must be addressed? And then finally Carolyn, there is a series of letters, one from Professor Oliver Weingärtner from Universitätsklinikum Jena and another from Professor Yasuyoshi Ouchi from Toranomon Hospital. They're exchanging letters debating the utility of lipid lowering with Ezetimibe in individuals over the age of 75 years. Dr Carolyn Lam: Very nice, Greg. Thanks so much. Shall we now move to our future discussion. Dr Greg Hundley: You bet. Well, welcome everyone. This is our feature discussion and today we're going to hear more about long QT syndrome. We have Dr Michael Gollob from University of Toronto and our own associate editor, Dr Sami Viskin from Tel Aviv Medical Center. Good morning. Good afternoon, gentlemen. Before we get started with a discussion of some of the study findings and results, Michael, could you tell us a little bit about why you performed the study and what were some of the hypotheses you wanted to test? Dr Michael Gollob: As you know, long QT syndrome is probably the most recognized channelopathy associated with sudden cardiac death in young individuals and adults. And at the present time, there are 17 genes available for clinical genetic testing in cases of suspected long QT syndrome. We simply ask the question, "Is there sufficient scientific evidence to support that each of these genes are single gene causes of long QT syndrome based on our contemporary knowledge of genetics and the human genome? Dr Greg Hundley: Great, Michael. So, can you tell us a little bit about your study population? How did you go about this and what was your study design? Dr Michael Gollob: We designed a methods approach that would assure that any conclusions that were made from our working group were not based on the opinions of one or two individuals. We wanted to ensure that this was a consensus conclusion with multiple experts in the field including genomic scientists, genetic counselors, inherited arrhythmia experts, and researchers in the field. We created three independent teams of genetic experts to curate the genetic evidence reported in the medical literature for each of these 17 reported causes of long QT syndrome. This was essentially an evidence-based approach using a pre-specified evidence-based matrix or scoring system depending on the level of evidence, genetic primarily, in the reported literature for each gene. Each of these curation teams worked independently of each other and they were blinded to each other's work and they were tasked with concluding whether a gene, based on the medical literature and the resource methodologies, had sufficient evidence for disease causation. Their classifications would be one of disputed evidence, limited evidence, moderate evidence, strong or definitive evidence for claims towards disease causation. Remarkably, independently, all of these teams reached the same conclusion. In the end, their summary data was reviewed by a clinical domain expert panel with individuals with expertise, particularly in long QT syndrome and other channelopathies. So in total 19 individuals reviewed all of the literature and the data presented and came to unanimous conclusions for each gene. Dr Greg Hundley: Out of the 17, were there some that were more important than others or was it uniformly all 17 were relevant? Dr Michael Gollob: Well, I think the most relevant conclusions of our study are that nine of these genes, more than half of these genes, were felt not to have sufficient evidence to support their causation as a single gene cause for typical long QT syndrome. So nine genes that are currently tested by clinical genetic testing providers do not have enough evidence to support their testing in patients with suspected long QT. And to us, that is the most relevant observation because testing genes that do not have sufficient evidence for disease causation poses a significant risk to patient harm and family harm. We concluded that only three genes had very definitive evidence for causation of long QT syndrome. Those three genes were KCNQ1, KCNH2, and SCN5A. There were another four genes that were concluded to have strong or definitive evidence for unusual presentations of long QT syndrome. And by that, I mean presentations that typically occur in the neonatal period and are associated with heart block seizures or developmental delay or in the case of one of these genes, Triadin, an autosomal recessive form of the disease. Dr Greg Hundley: So helping us perhaps what types of genes to screen for when we have someone with this condition or suspected. So Sami, can you help us put this into perspective? How does this study help us in management of this clinical situation. Dr Sami Viskin: In Circulation, we immediately recognize the importance of the manuscript, the importance of the study because unfortunately, there are too many physicians all over who will accept the results of genetic testing essentially like gospel. Now it's in the DNA, it's in the genes, so whatever you find must be true. And too often, clinical decisions on treatment including ICD implantation have been undertaken based on results of genetic testing’s; thus are wrongly interpreted. So we recognize immediately the importance of this paper. We already had a different study by Dr Gollob and his associates. Again, reassessing the role of genes in Brugada syndrome. So we were familiar with this type of analysis. We recognize the importance and we moved ahead to accept this paper, it went fairly easily, I think only one revision. At the same time, we were getting additional paper by other groups. So in the same issue, we have two more papers, one from Jason Roberts with the International Long QT Registry of long QT 5, reaching similar conclusions that this is a gene with very limited penetrants and another study by the Mayo clinic also showing that many of the genes who are not the major genes are overrepresented in the healthy population. So we put all these three papers together with a very nice editorial by Chris Semsarian in the same issue. So everything is put in the right perspective of how we should be looking at all the genes of these disease in a different way. Dr Greg Hundley: So as a clinician quickly, how can I use this information in the issue, perhaps this paper and all three, in management of patients with either suspected or long QT syndrome? Dr Michael Gollob: First off, I would emphasize that the diagnosis of long QT syndrome or any genetic base disease for that matter, should be based on clinical phenotype and not the observation of a genetic change, particularly if genes are being tested that do not have strong evidence for disease causation, as is the case for the nine genes that we've pointed out in this manuscript. So I think clinicians need to be wary of the genetic testing panels that they are requesting be screened or used in the assessment of their patients and be knowledgeable that at this point in time, we really only have three genes with very strong evidence to support disease causation of the typical form of long QT syndrome. And that for the most part, these other genes should not be tested or should only remain in the realm of research. I think that responsibility extends further than just the clinician taking care of the patient, but also clinical genetic testing providers, companies that offer these genetic testing services. I think they should assume a responsibility to ensure that they are only offering services for genes that have strong evidence for disease causation because when they report results in genes that are not valid for the disease, that only confuses the care of the patient and that creates a risk of harm to them if that information is misinterpreted by a physician. As Dr Viskin or Sami pointed out, we do see patients who are inappropriately diagnosed. We remove the diagnosis of roughly 10 to 20% of cases in our own clinic. And unfortunately, many of these patients and their families have suffered undue anxiety. Some of them have ICDs in place that should not have been there. So I think overall, the field needs to be aware of what genes are relevant and what genes still are within the realm of research. Dr Greg Hundley: Can you tell us just quickly Michael and then also Sami, what do you see as the next study in this field? Dr Michael Gollob: We're taking a step back now. The first decade of this century saw an exponential growth in reported gene disease associations. And now in the last five or six years, we've learned a lot about human genetic variation, which has provided us an opportunity to reflect back on some of these previous and reported genes as causes for long QT and other diseases. So I think many individuals in our field may say, "Well, you know, this is disappointing. We believed in these genes. We really thought these genes were causes of long QT." And to that point I would say, we need more research. If you believe in some of these genes that have now been considered to have limited or disputed evidence, research should continue if these remain plausible candidates for the disease. So I think future research has to continue. There are probably still a few other genes that have not yet been discovered. I think we've got the vast majority. I think in most cases, at least in our experience, 90 to 95% of cases are explained by the top three genes. But there are probably other genes out there and it's always fascinating to learn or discover new genes, but those sorts of studies have to be done with the correct methodologies and rigid protocols. Lastly, I think in the future us clinicians and geneticists and genetic counselors need to work closely with genetic testing providers to ensure that they are offering responsible genetic testing services. Dr Greg Hundley: Sami, do you have anything to add? Dr Sami Viskin: Just congratulate the authors. I think they did a very great service to the medical community by pointing out the limitations of the genetic testing and the way we interpret the results, and they deserve to be applauded for reminding us that we have to be careful when we read papers about genetic results or when we get genetic testing results ourselves. Dr Greg Hundley: I want to thank Michael from University of Toronto and Sami from Tel Aviv Medical Center for participating. And on behalf of both Carolyn and myself, wish you all a great week and look forward to chatting with you next week. This program is copyright, the American Heart Association 2020.  

Speaker 1:           Hi, everyone. Welcome to episode 21 of Getting Personal, Omics of the Heart from October 2018. I'm Jane Ferguson, an Assistant Professor at Vanderbilt University Medical Center and an Associate Editor at Circulation: Genomic and Precision Medicine. We have a great issue this month. So, let's dive straight in. First up, an article on "Loss-of-Function ABCC8 Mutations in Pulmonary Arterial Hypertension" from Michael Bohnen, Wendy Chung and colleagues from Columbia University. In pulmonary arterial hypertension, or PAH, compromised pulmonary arterial function can raise pressure in the pulmonary artery which leads to increased pulmonary vascular resistance. This ultimately results in right heart failure. While PAH is relatively rare, it has a high rate of mortality. Some genetic underpinnings have been identified, notably the KCNK3 gene identified by the same research group where they find that mutations result in potassium channelopathy. However, here the authors hypothesized that other genetic contributors also exist and that identification of these could highlight new therapeutic targets to improve treatment and outcomes in PAH. In their study, the authors performed exome sequencing for discovery of novel disease variants in 233 PAH patients, 99 of whom had pediatric-onset and 134 with adult-onset. They sequenced a replication sample of 680 individuals with adult-onset PAH. They found a de novo missense variant in the ABCC8 gene in one patient and then found 10 more ABCC8 variants in other unrelated patients in the discovery and replication samples. Half of these were novel mutations and all were located in conserved regions and predicted to be deleterious. They screened over 33,000 subjects from the Exome Aggregation Consortium and over 49,000 from the Regeneron-Geisinger DiscovEHR study and found significant overrepresentation on rare ABCC8 variants in the PAH cases compared with population controls. ABCC8 encodes sulfonylurea receptor ... part of the potassium ATP channel. The authors determined that it is expressed in lungs in both PAH and healthy individuals and is particularly localized to alveolar macrophages and proximal pulmonary arteries. They expressed eight of the newly discovered ABCC8 mutations in COS cells, which are a monkey-derived, fiberglass-like cell line and they assessed the effects on function. They used patch-clamp experiments to assess potassium ATP channel activity and recorded efflux rates of Rubidium-86. Every mutation was associated with impairments in one or both functional assays, suggesting that mutations in ABCC8 are responsible for PAH by a modulating potassium channel function and flux. An existing drug, Diazoxide, targets ABCC8 and has anti-hypertensive and insulin-lowering effects. The authors find that all mutants were pharmacologically activated by Diazoxide in the functional assays. Now, whether this drug would be safe or effective in PAH remains unknown, but these findings open up targeting of ABCC8 as a possible treatment in PaH and highlight the importance of potassium channels in PAH. Our next paper also used whole-exome sequencing for novel discovery. Marzia de Bortoli, Alessandra Rampazza and colleagues from the University of Padua in Italy published "Whole-Exome Sequencing Identifies Pathogenic Variants in TJP1 Gene Associated With Arrhythmogenic Cardiomyopathy". Arrhythmogenic Cardiomyopathy, or ACM, is one of the most common causes of sudden unexpected death in athletes and young people. It is known to be frequently caused by mutations in genes encoding mechanical junction proteins of the intercalated disks within the cardiac muscle. However, some individuals with ACM do not have any mutations in known genes. This research group was interested in finding novel causal gene mutation and they use whole-exome sequencing to identify mutations from a single patient in Italy. They used InSilica tools to screen for potentially damaging mutations which brought their list of candidate mutations down to 52 and this was topped by a novel mutation in the TJP1 gene which was predicted to be highly deleterious using various algorithms. Using Sanger sequencing, they found that this mutation was also present in several family members. A second mutation in TJP1, also predicted to be damaging, was identified in a second Italian family. They then screened a sample of 43 Dutch and German subjects diagnosed with ACM and found that, once again, mutations in TJP1 topped the list as predicted to be damaging. The TJP1, or tight junction protein 1, encodes the intercalated disk proteins ZO1. The identified mutations may affect folding and local interactions within the protein, affecting protein-protein interactions and gap junction organization. Well, within this paper, they were not able to fully disentangle the mechanisms linking these mutations to disease, given that the prevalence of TJP1 mutations in their ACM samples was almost 5%. Screening for TJP1 mutations in ACM cohorts may identify many additional affected subjects. Further research into TJP1 is needed to identify how these variants may cause ACM. If you want to read more about this paper, you can check out the accompanying editorial from Jason Roberts ... Western University, Ontario ... in this same issue. Next up is a paper from Natsuko Tamura, Yasuhiro Maejima, Mitsuaki Isobe and colleagues from Tokyo Medical and Dental University entitled "Single-nucleotide Polymorphism of the MLX Gene Is Associated With Takayasu Arteritis". Takayasu Arteritis, or TAK, is an autoimmune disease causing aortic vasculitis that is poorly understood and disproportionately affects young Asian women. In previous genome-wide associations, study of TAK in Japanese individuals conducted by this group, indicated SNPs in the MLX gene. In this paper, the authors aim to identify mechanisms linking MLX mutations with TAK. The top GWAS SNP rs665268 is a missense mutation causing L-Glutamine Arginine substitution in the DNA binding site of MLX. They found that this SNP was associated with severity in disease in TAK. With additional copies of the risk alleles associated with more severe aortic regurgitation and greater number arterial lesions. In mice, the highest expression of MLX was found in the aortic valves. Using crystallography, they found that the missense mutation likely stabilizes a complex formed between MLX and MondoA. Immunoprecipitation experiments confirmed that the missense mutation was associated with enhanced MLX MondoA heterodimer formation and MLX transcriptional activity. This resulted in upregulation of TXNIP and higher TXNIP expression is associated with increased intracellular oxidative stress and the authors found for increased oxidative stress in cells carrying the MLX mutation. Further, additional cell experiments showed evidence of this MLX mutation reduces autophagy and stimulates inflammasome activation. Overall, through a series of really elegant experiments, the authors demonstrate that a missense mutation in MLX leads to inflammasome activation and accumulation of cells within the aorta, potentially underlying the pathophysiology seen in TAK patients and highlighting novel causal pathways that may be probed therapeutically.regular Our next paper from Danxin Wang, Wolfgang Sadee and colleagues from the University of Florida and The Ohio State University, also delves into the functional impact of disease-associated SNPs. In their paper, "Interactions Between Regulatory Variants in CYP7A1 Promoter and Enhancer Regions Regulate CYP7A1 Expression", they used a series of experiments to demonstrate how SNPs in CYP7A1 ... which have been associated with cholesterol and cardiovascular disease ... are related to gene function. CYP7A1 is a gene which coordinates a key pathway for cholesterol removal from the body because it encodes an enzyme which is rate-limiting for bioassay synthesis from cholesterol. Although several SNPs in the gene have been associated with cardiovascular phenotypes, the reported effects on gene function have been inconsistent and/or unclear. Because of the linkage disequilibrium between SNPs, it has been hard to understand which SNP or SNPs are actually functional. What this team set out to do was to systematically screen functionality of individual CYP7A1 SNPs to understand the independent effects of each functional variant. First, they used chromatin conformation capture, or 4C assay, to identify regions that associated with a CYP7A1 promoter. They found three distinct regions with evidence of enhancer function and [phonetic 00:09:05] active A>G regulation. They, next, used CRISPR Cas9 to delete each of the three regions in HepG2 cells and assess effects on CYP7A1 expression. One region had no effect, while one led to increased expression and one led to decreased expression ... thus, identifying the presence of both enhancer and repressor regions. Using reporter gene assays, they confirmed the effects seen in CRISPR experiments. Based on reported SNP associations, they narrowed down candidate functional SNPs within the regions and constructed reporter assays containing haplotypes of potential functional SNPs. They were able to identify two SNPs acting together to determine differences in CYP7A1 gene expression. Because these SNPs are in LD, but the minor alleles have effects in opposite directions, considering genotype at both SNPs is required to understand the effects on gene expression. This explains why previous studies found inconsistent results. Both during the functional experiments, they went to human samples and they assessed the combined effect of the two SNPs on clinical phenotypes. Designating people as high or low activity based on the two SNPs, they found significant differences in cholesterol and in the likelihood to reach cholesterol targets on statin, as well as in the risk of MI. This paper is a lovely example of how careful functional interrogation can tease out a complex problem and I think it highlights how much more of this type of work needs to be done for the many other genomic regions with confusing or discord in associations. The last full-length article concerns the "Effect of Ascertainment Bias on Estimates of Patient Mortality in Inherited Cardiac Diseases" and comes from Eline Nannenberg, Imke Christiaans and colleagues at the Academic Medical Center, Amsterdam. They were interested in how much ascertainment bias and the tendency to publish findings from more severe disease cases affects the mortality estimates that are used to guide clinicians and genetic counselors when helping patients understand their disease prognosis. They revisited three inherited cardiac diseases including idiopathic ventricular fibrillation associated with a mutation in DPP6, SCN5A overlap syndrome associated with SCN5A mutations, and Arrhythmogenic Cardiomyopathy caused by a founder PLN mutation. They analyzed mortality over 2-10 years of clinical screening and cascade screening and found that the median age of survival quickly increased in all three conditions. In many cases, the reason that a mutation was identified was because of severe disease in that patient or family, but as the authors highlight here, this can bias publications towards associating the variant with more severe phenotypes and higher mortality. Following up the initial findings with additional screening and tracking of affected individuals is important to subsequently give a more accurate estimation of the effect of the mutation which can be used to inform treatment plans. Moving on to this month's research letters, Catherine Hajek, Jerome Rotter and colleagues from LA BioMed and the University of South Dakota, published the results of their study, "A Coronary Heart Disease Genetic Risk Score Predicts Cardiovascular Disease Risk in Men, Not Women: The Multi-Ethnic Study of Atherosclerosis". The genetic risk scores are being increasingly applied to estimate disease risk in individuals. However, these scores are based on the GWAS discovery from specific populations which have often been disproportionately male and with individuals of European ancestry. In this letter, the authors wanted to understand whether coronary heart disease genetic risk scores performed the same in men and women of European ancestry. Using data from the MESA Study, they applied a 46 locus genetic risk score to over 2500 individuals. In men, this risk score was strongly associated with event rates. However, in women, there was no association. Given the known differences in disease pathophysiology and manifestation between men and women, this finding additionally highlights the need to conduct genetic studies in underrepresented groups so that we can design scores that accurately predict risk within specific groups. Our next letter comes from Xiao Wang and Kiran Musunru at the University of Pennsylvania ... "Confirmation of Causal rs9349379- PHACTR1 Expression Quantitative Trait Locus in iPSC Endothelial Cells". They were interested in understanding the affect of a coronary disease SNP in the PHACTR1 gene on gene expression. Previous efforts to investigate this had yielded conflicting results showing either a significant eQTL effect for PHACTR1 and vascular tissue or no effect on PHACTR1, but an effect on a distal gene EDN1 in endothelial cells. For this study, the authors used CRISPR Cas9 to introduce the SNP to iPS cells and then expanded isogenic lines at the major and minor allele homozygous and differentiated these into endothelial cells. They find that the major allele was associated with significantly higher factorial expression, but no difference in EDN1 expression. Thus, based on these experiments, it appears that PHACTR1 may indeed be the causal gene in that region underlying the GWAS signal and whether or not EDN1 is involved remains unclear. Our next letter is a clinical letter from Nosheen Raza, Anjali Owens and co-authors at the University of Pennsylvania. They report on "ACTA1 Novel Likely Pathogenic Variant in a Family With Dilated Cardiomyopathy". In this case report, they describe that the discovery of a mutation in ACTA1 in a family with dilated cardiomyopathy, but no skeletal muscle symptoms. As a gene that is predominantly expressed in skeletal muscle, ACTA1 mutations have previously been associated with skeletal muscle myopathies and would not have been expected to cause cardiac symptoms in the absence of skeletal muscle dysfunction. However, sequencing suggests that this variant is a causal mutation in this family, highlighting the need to consider potential mechanisms for cardiac muscle specifics of highly expressed skeletal muscle genes. Our second clinical letter comes from Laura Zahavich, Seema Mital and co-authors from the Hospital for Sick Children in Ontario. They report a "Novel Association of a De Novo CALM2 Mutation With Long QT Syndrome and Hypertrophic Cardiomyopathy". They report finding mutation in the calcium transporter CALM2 gene in the child who presented with hypertrophic cardiomyopathy and ultimately died from sudden cardiac death. While this patient also had some variants of un-insignificance, the CALM2 gene is highly conserved and mutations are likely to be pathogenic. The CALM2 is not on all of the clinical genetic testing panels and in this case, whole-exome sequencing was required to identify a mutation. CALM2 have been described in other individuals and together with the findings reported here, there's compelling evidence for inclusion of CALM2 on cardiomyopathy in clinical testing panels. This issue also contains a perspective article from Michael Mackley, Elizabeth Ormondroyd and colleagues from the University of Oxford entitled "From Genotype to Phenotype: Clinical Assessment and Participant Perspective of a Secondary Genomic Finding Associated with Long QT Syndrome". They describe some of the challenges arising from more widespread genetic testing including how to deal with incidental findings. A larger number of people including apparently healthy individuals are receiving sequencing results that highlight potential disease-related mutations, but with varying penetrance and uncertain effects. This perspective paper highlights the issues through case study and discusses future directions and challenges in this rapidly growing area. Finally, we ride out this issue with an AHA scientific statement on "Cardiovascular Health in Turner Syndrome: A Scientific Statement From the American Heart Association" led by Michael Silberbach and Jolien Roos-Hesselink and a group of co-authors representing the American Heart Association Council on Cardiovascular Disease in the Young; Council on Genomic and Precision Medicine; and Council on Peripheral Vascular Disease. In this statement, they discuss the cardiovascular complications that commonly occur in girls and women Turner syndrome. Cardiovascular disease contributes significantly to premature death in individuals with Turner syndrome. Because of the unique nature of the cardiac presentations in Turner syndrome, better clinical guidelines are needed to improve diagnosis and treatment of [phonetic 00:17:26] ischemia in these individuals. This statement takes a first step to outline suggestions to improve clinical practice and highlights the work that still remains to be done to inform disease management. That rounds out the October issue of Circulation: Genomic and Precision Medicine. Thanks for listening! You can go online to ahajournals.org/journal/circgen to access the latest issue and browse previous issues. As a last reminder, AHA Sessions is approaching fast and I hope to see many of you in Chicago, November 10-12. 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.  

Jane Ferguson:                 Hi, everyone. Welcome to Getting Personal: Omics of the Heart. This is podcast episode 16 from May 2018. I'm Jane Ferguson from Vanderbilt University Medical Center and this podcast is brought to you by Circulation Genomic and Precision Medicine and the AHA Council on Genomic and Precision Medicine. Jane Ferguson:                 This month we talked to Dr. Caitrin McDonough from the University of Florida. We briefly mentioned her paper in last month's episode Genetic Variants Influencing Plasma Renin Activity in Hypertensive Patients From the PEAR Study, but we wanted to go into it in more depth this month. Caitrin shared with us that this manuscript actually resulted from student course work and was a collaborative effort between students and instructors. The manuscript highlights has successful as approach can be both in increasing student engagement and as an effective way to do high quality research. You can hear her talk more about her innovative approach to student learning and the study findings later in this episode. Jane Ferguson:                 Of course, we have a great lineup of papers in Circulation Genomic and Precision Medicine this month. First up, a paper entitled, "SCN5A Variant Functional Perturbation and Clinical Presentation Variants of a Certain Significance" by Brett Kroncke, Andrew Glazer, and Dan M. Roden and colleagues from Vanderbilt University Medical Center. They were interested in investigating the functional significance of variants in the cardiac sodium channel in particular to see if they could explain why some variant carriers present with cardiac arrhythmias while others remain asymptomatic. Through a comprehensive literature search, they identified 1712 SCN5A variants and characterized the carriers by disease presentation. Variants associated with disease were more likely to fall in transmembrane domains consistent with the importance of these domains for channel function. Jane Ferguson:                 Using American College of Medical Genetics Criteria for variant classification, they found that variants classified as more pathogenic were also more penetrant. Penetrance was also associated with electrophysiological parameters. This approach highlights how modeling the penetrance of different variants can help define disease risk for individuals who carry potentially pathogenic variants. Jane Ferguson:                 Next we have a paper from Vincenzo Macri, Jennifer Brody, Patrick Ellinor, Nona Sotoodehnia and colleagues from the University of Washington and Massachusets General Hospital. This is also related to sodium channels and the paper is entitled, "Common Coding Variants in SCN10A Are Associated With the Nav1.8 Late Current and Cardiac Conduction". They were interested in SCN10A and sequenced this gene in over 3600 individuals from the CHARGE consortium to identify variants associated with cardiac conduction. They were able to replicate associations between variants and PR and the QRS intervals in a sample of almost 21,000 individuals from the CHARGE Exome sample. They identified several missense variants have clustered into distinct haplotypes and they showed that these haplotypes were associated with late sodium current. Jane Ferguson:                 Continuing the cardiac conduction theme, Honghuang Lin,  Aaron Isaacs and colleagues published a manuscript entitled, "Common and Rare Coding Genetic Variation Underlying the Electrocardiographic PR Interval". They conducted a meta-analyses of PR interval in over 93000 individuals which included over 9000 individuals of African ancestry. They identified 31 loci, 11 of which have not been reported before. We see SCN5A come up again as a gene of interest in this study but their analyses also implicated a novel locus, MYH6. Jane Ferguson:                 Next up moving from the heart to the vasculature, Janne Pott, Markus Scholz and colleagues from the University of Leipzig published a manuscript entitled, "Genetic Regulation of PCSK9 Plasma Levels and Its Impact on Atherosclerotic Vascular Disease Phenotypes". They were interested in whether circulating PCSK9 can be used as a diagnostic or predictive biomarker. To address this, they conducted a GWAS of plasma PCSK9 in over 3000 individuals from the LIFE-Heart study. They found that several independent variants within the PCSK9 gene were associated with plasma PCSK9 as well as some suggestive variants in another gene locus FBXL18. They used Mendelian randomization to probe causality and the data suggest that PCSK9 variants have a causal role in the presence and severity of atherosclerosis. Jane Ferguson:                 Moving on to another biomarker, Lisanne Blauw, Ko Willems van Dijk and colleagues from the  Einthoven Laboratory for Experimental Vascular Medicine report on CETP in their manuscript Cholesteryl Ester Transfer Protein Concentration A Genome-Wide Association Study Followed by Mendelian Randomization on Coronary Artery Disease. They aimed to assess potential causal effects of circulating CDP on cardiovascular disease through GWAS and Mendelian randomization. Jane Ferguson:                 In a study of over 4000 individuals from the Netherlands Epidemiology of Obesity Study, they identified three variants in CTP that associated with plasma levels of CETP and explained over 16% in the total variation in CDP levels. Genetically predicted in CETP was associated with reduced HDL and LDL cholesterol suggesting that CETP may be causally associated with coronary disease. Jane Ferguson:                 Rounding out the table of contents we also have a clinical case perspective from Nosheen Reza, Anjali The Importance of Timely Genetic Evaluation in family members in cases of cardiac disfunction and cardiomyopathy. We have a report from Adrianna Vlachos, Jeffrey Lipton and colleagues on the Diamond Blackfan Anemia Registry and we have a clinical case from Yukihiro Saito, Hiroshi Ito and colleagues on TRP and poor mutations in patients with ventricular non-compaction and cardiac conduction disease. Jane Ferguson:                 To read all of these papers and the accompanying commentaries, log on to circgenetics.aha.journals.org and if you're a visual learner or you need a work related excuse to spend time on YouTube, you can also access video summaries of all our articles from the CircGen website or directly from our YouTube channel Circulation Journal. Lastly, follow us on Twitter at circ_gen or on Facebook to get new content directly in your feed. Jane Ferguson:                 I'm joined today by Caitrin McDonough from the University of Florida and Caitrin is an Assistant Professor in the Department of Pharmacotherapy and Translational research in the College of Pharmacy and she's the first author on a recently published manuscript entitled, "Genetic Variants Influencing Plasma Renin Activity in Hypertensive Patients From the PEAR Study". This was published in the April 2018 issue of Circulation Genomic and Precision Medicine. Welcome, Caitrin. Caitrin M.:                           Thank you. Jane Ferguson:                 For listeners who haven't had a chance to read the paper yet, I wonder could you give us a brief overview of what prompted you to do this study? Caitrin M.:                           Sure so this looks at plasma renin activity and just initially a GWAS but it was done in a hypertensive population from the pharmogenomic evaluation of antihypertensive responses study. Particularly, since our group here at the University of Florida is more interested in pharmacogenomics we wanted to address plasma renin since it can influence blood pressure response to antihypertensive medication particularly if you use it as something to predict but also to correlate it with that as there have been also prior data from our group that shows if you have different levels of plasma renin that would predict if you would respond better to certain types of antihypertensive medications such as a beta-blocker or a diuretic. Caitrin M.:                           We used both a GWAS approach as well as a prioritization through blood pressure response to focus in on signals and then furthered by using prioritization using data from RNA seq and looking at eQTLs and then finally looking at more of just a traditional net replication of the original plasma renin activity signal. Caitrin M.:                           Overall, one of the interesting things and why we were initially doing this study was really in connection with a graduate course that myself and another faculty member here who's also an author on the paper, Yan Gong [inaudible 00:09:12]. We often have the students analyze data from the PEAR study as we have a lot of data from that study and it helped us analyze additional papers but we didn't necessarily know if this was going to be an interesting phenotype but through that course work which turned out that it really did have some interesting signals so we wanted to follow up more on. Jane Ferguson:                 Yeah, I love that approach so I think that's a really smart way to do it. To actually get your students to analyze your data and get them really involved in the process. How much then did the students ... how much were then they able to get involved when it started transpiring that their results would actually be something that could be put together for a manuscript? Caitrin M.:                           Overall, they are fairly involved. During the course work, what we usually do is give them just directly types data since a lot of them have not done this type of genetic analysis before and we split it up where each student gets about four to five chromosomes of data and then different phenotypes in the different race groups as we have both whites and African Americans. They get a certain race group, certain number of chromosomes and so they're able to conduct the analysis just using the Uplink software which is fairly user-friendly and straightforward. Then they get experience making Manhattan plots and using LocusZoom. Caitrin M.:                           After they have the basic techniques, then we teach them how to start following up top signals and determine what is a good signal. They're looking at the LD or SNP function or possibly gene function or looking at their genotype, phenotype relationships and making sure that it's not just one person who's driving the whole signal. Then selecting what top reasons and top SNPs may need a follow up. That part they all do there in the class and learn more of the basics. Caitrin M.:                           After the class, the students who want to continue to participate we get together and redistribute data where they would then move on to working on the imputed data sets and we teach them how to do that. Then we give them ... operate it somewhat similar to a consortia level meta-analysis type thing. I write up an analysis plan, each student does some part of the analysis. They have to bring it all back to me. I sort through it. We meet and go through it. Then we set our next steps to follow up. Then different students get different SNPs to investigate the function of or different subanalyses to do. Caitrin M.:                           One of our graduate students who is on this particular project, her dissertation project was very focused on our RNA seq data so that was how we were able to bring in the eQTL analysis using the RNA seq data as she had done a lot of the groundwork with that already. In one of our discussions that was one of the ways that we were able to incorporate the prioritization since she was intimately familiar with that data set. Jane Ferguson:                 Yeah and I think that's great. I can imagine that, that's a much more compelling way for students to learn about how to analyze data when they see the natural follow through. Do you find that some of the students maybe get more excited about research or are more likely to pursue future research opportunities by having had this hands on experience with the publication process and completing a project really did to this very end? Caitrin M.:                           They do, yeah. I see some of the students that end up sticking with it more are the students who I work more closely with and see more closely some of the students who are from other departments still stay involved but sometimes don't stay quite as involved. But, all of them really do continue to follow up and ask if they can still help or if there's anything they need to do until we get it to publication which is really nice. Jane Ferguson:                 Yeah, right. I think that's fantastic and I'm sure every study has its challenges. I'm interested what were the challenges you encountered in doing this study and which one of them may be unique to the way you have a lot of different people analyzing different aspects of the data versus the regular challenges that would come up in a study like this. Caitrin M.:                           Yeah so some of it I think is just keeping everyone on track and keeping it organized, making sure I think some of our challenges with this study was just me making I think on a lot of other studies, while I had certainly hands on the data it was more of an oversight rule for some pieces of it and just making sure everything looked the way that I thought it did, double checking. Some of it I think the teaching aspect of it just making sure everything was also done correctly and then keeping everything organized made the study a little bit more challenging. Caitrin M.:                           I think part of it too was with the PEAR study, it is a very rich data set. Determining what we wanted for our prioritization scheme and how to work through the different types of data sets that we had and put it all together as initially we just assign each student a different piece and we had a vague plan but it was a little bit more tricky as to work through how it was all coming together then when everyone came back together since a lot of people were doing as opposed to just one person doing it. Jane Ferguson:                 Right, so yeah and I think you're touching on the part that all of us have when we're writing papers that you sometimes end up with a lot of data at the beginning, you're trying to sift through it and then sometimes at a certain point you see something and you're like, "Okay, yes. This is interesting." Then you start following it up. Jane Ferguson:                 I wonder at what point did that happen? I suppose you probably ... You ran the GWAS for plasma renin activity and then find a number of suggested SNPs that were significant you associated but then ... Describe your strategy and you did so the second screening stuff to look at the pharmacological aspect defining [crosstalk 00:15:12]? Caitrin M.:                           Yeah, our initial plan going in was the first two steps, to do the GWAS for plasma renin activity and then to do the prioritization through blood pressure responses. I was very familiar with what our lab was familiar with but then after we got there, I think we were then troubled with what we did next and where to go. When we decided to bring in the RNA seq data, I think that was when it really started coming together as our top signal, the SNN-TXNDC11 gene region really stuck out then and it showed up. That seemed like a much stronger signal and it gave us a little bit more focus and also brought it much more of a functional aspect where we would maybe start to believe that signal more. That I think was really when we did that more of a turning point for the study and helped us focus more on where then to go with the results. Jane Ferguson:                 As far as the data you had I think over 700 people for your GWAS. Then you had a pretty large number of ... Was it the same subjects or different subjects where you also had the RNA seq data to do the QTL analysis? Caitrin M.:                           The same subject so not everyone has RNA seq. We have RNA seq data on 50 individuals and they were selected from whites and at the extremes of the blood pressure response so that it has a slightly interesting selection process. It's the main data analysis there was a best responder, worse responder to thiazide diuretics. Caitrin M.:                           When we do the eQTL analysis, we aren't always sure what we're going to get since we're missing the middle of blood pressure response. But, when we're just looking strictly at eQTL analysis sometimes we get lucky and sometimes it looks weird. Jane Ferguson:                 In your case as well you had the added issue of subjects were randomized to drug treatment so it was some where responders were ... I guess some people got the drug that worked for them and some people did not get the drug that worked for them. Caitrin M.:                           Yeah. Jane Ferguson:                 Did you I guess were incorporating both groups so good responders to either and some of that was because of their gene. They got the right drug for their genotype. Caitrin M.:                           Exactly, yeah. Jane Ferguson:                 It's good and then you were able to replicate this. After you were able to prioritize your gene region based on the GWAS and the drug response and the eQTL data, you actually ended up being able to go to a second sample to replicate the association right? Caitrin M.:                           Yes, it was in a lot of the same investigators, we have a second study PEAR-2, which has a very similar design to the PEAR study but used different drugs but also collected baseline plasma renin activity. We were able to use that phenotype again. We did have slight differences in GWAS to imputation panels at that point in time for when we were conducting this study so we ended up using a proxy to replicate but we did see the same signal in the second population which was very nice to see. Jane Ferguson:                 What is known about this gene region or either of these two genes? Caitrin M.:                           Overall, that was I think one of our harder points when we started trying to make the connections back to our phenotype. This was one of the areas where we did also have help from our students and the students as that was part of their initial training where they really looked to see what function was of various different genes and how to follow them up. That was one area where they came in, was to help look up some of the function of these ... there have been some connections with the various genes, the other phenotypes and with SNN and to atherosclerosis and other inflammatory cytokines such as TNF-alpha. Then there have been data also from [inaudible 00:19:37] that really show that there is an eQTL in this region that which supports what we saw in our own data. However, there really wasn't any direct connections with renin and the renin angiotensin aldosterone system and blood pressure regulation that we could find in the literature. Caitrin M.:                           We're not exactly sure how it connects but based off of our functional data and levels of evidence and then we saw some of that in publicly available data, we're still very interested in the region. Jane Ferguson:                 I think the data is compelling enough that it looks like you've identified the new region that probably is the mechanistically related that will require a whole bunch of basic mechanistic research to figure out what exactly the genes in this region are doing and how this ultimately connect back to blood pressure and response to drug therapy. Caitrin M.:                           Exactly. Jane Ferguson:                 I could see this ... I mean obviously there's a whole lot of potential functional work there and then probably also the clinical work, I wonder what you think about how this would affect any pharmacogenetic therapeutic ... You know at present I think you can look at plasma renin activity and use that as a predictor of drug response to help guide therapies. Would you think that a genotype guided therapy may end up being more effective than the plasma renin activity measurement in this case? Caitrin M.:                           In this case since this is so connected with a phenotype that you could use with plasma renin, I think if you're able to draw a plasma renin you may just want to do that. I think our overall goal would be if someone had preexisting genetic data and you weren't wanting to do an additional test or if you're contemplating response to a lot of different drugs that perhaps you could use a genetic data. One of the issues that was brought up on review and that are a lot of group considers quite a lot is that we have a lot of signals and that our group has certainly published a lot in this area and there's a lot of signals that we have to a lot of different drugs and how do you incorporate all of them together, is there overlap between them or where do they all fall? Caitrin M.:                           That is certainly something that we're still working on as more I think ultimate goal would be more to delve more of a SNP score or gene score and some type of risk score that would help you determine what drug you would best respond to. We've done that a little bit in some of our prior publications but we haven't yet taken all of our data together and help to build something that would if you had a lot of data on an individual and various different alleles at various different genes, how that would respond. Caitrin M.:                           Overall, when we look at blood pressure response as a pharmacogenetic signal, certainly we see larger affect sizes than you would in disease genetics but we're not seeing affect sizes like you would with more of an adverse drug event. We're in between there and we're often times it's not necessarily just going to be one SNP or one gene that would tell your whole story but a combination of quite a few of them. Jane Ferguson:                 I wonder are there more similar stories like this from the same data set? You know you've been through this process from start to finish and building in the functional work and do you think that next year's class will be able to do this again with the same data set? That maybe pick one of the next priority candidate down the list and maybe find another interesting story like this? Caitrin M.:                           Yeah, so we actually just finished our class this year and they looked at potassium. We just got done grading final papers and submitting grades so we will over the summer be working with them a little bit more. I think some of our new graduate students too are starting to work on trying to make more connections between a lot of our different phenotypes and as you start to layer those together what it exactly means for a patient or implementation perspective. Jane Ferguson:                 Yeah, interesting. We'll have to look for that story whenever you guys get done with it. Otherwise, are you planning on following up this specific SNP region in any other way or any other studies? Where's next for you guys overall? Caitrin M.:                           I think one of the things we would like to do is look at this more in PEAR-2. We really just brought the PEAR-2 data set in here as replication of the top region in that last stage but we have that data set and we can certainly look at that data set. Caitrin M.:                           The other thing that I would like to do is as we started this project in conjunction with the class that was a couple of years ago at this point in time, we used [TAP/MAP 3 00:24:35] imputed data since that was what we had in the lab and what we were using at that point in time. At this point in time, we have now imputed both PEAR and PEAR-2 2000 genomes phase three data. It'd be interesting to see if we are able to see any additional signals or if these regions become stronger or exactly what would happen using a more imputation panel that has more coverage and where we would have the same panel between both PEAR and PEAR-2. Jane Ferguson:                 Right because you may or may not have identified the causal SNPs in the previous access but- Caitrin M.:                           Yeah. Jane Ferguson:                 -yeah so it'd be nice to see if you can actually get that out. That potentially could end being a drugable target maybe suitable for something more specific but who knows. Is there anything else that we haven't covered yet that you'd like to mention? Caitrin M.:                           Overall, I think that just this type of model of utilizing more of a real world analysis and data in a class project really certainly engages our students a lot and I think they all enjoy actually being able to work with data that came out of this study and have a lot more hands-on experience and really project-based analysis experience. We've been very happy with this model and have used it multiple times. We have an HDL paper, the renin paper, our glucose response paper and now we're working on the potassium project. It's been a good model for us here with our pharmacogenomics class. Jane Ferguson:                 Yeah, I mean I think it's a really smart and intuitive way to think about education. It's mutually beneficial it sounds like, so it's helping you guys get your data analyzed. It's really helping the students learn so I think it's a win-win situation. I think it's a model that a lot of other people would really be interested in adopting. Caitrin M.:                           Yeah. Jane Ferguson:                 Okay well thanks so much for talking to me and talking about your model and your research. It's been great. Caitrin M.:                           Yes, thank you very much for having me. Jane Ferguson:                 That's it from us for May. Thank you for listening and come back for more next month.  

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. 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. Our featured paper today provides important trial evidence that will guide interventional management of symptomatic femoral artery disease, but first, here's your summary of this week's journal.                                                 The first paper sheds light on the interaction between left ventricular dysfunction and mesenchymal stromal cell activation. First author, Dr. Naftali-Shani. Corresponding author, Dr. Leor and colleagues from Neufeld Cardiac Research Institute in Israel isolated mesenchymal stromal cells from cardiac and subcutaneous fat tissues of mice with left ventricular dysfunction, 28 days after myocardial infarction or sham operation. They further injected mesenchymal stromal cells or saline into the infracted myocardium of mice and evaluated left ventricular remodeling 28 days after myocardial infarction. They found that left ventricular dysfunction switched cardiac mesenchymal stromal cells towards an inflammatory phenotype and that these pro-inflammatory mesenchymal stromal cells contributed to adverse left ventricular remodeling and dysfunction. The inflammatory polarization of cardiac mesenchymal stromal cells by left ventricular dysfunction was mediated by toll-like receptor four. Finally, toll-like receptor four deficiency in mesenchymal stromal cells attenuated their pro-inflammatory activation, improved their reparative properties, graft survival, infarct repair and left ventricular remodeling.                                                 In summary, the environment of the failing and infarcted myocardium drove resident and transplanted mesenchymal stromal cells towards a pro-inflammatory phenotype that restricted their survival and reparative effects in a mechanism mediated by toll-like receptor four. Targeting toll-like receptor four in mesenchymal stromal cells could improve the safety and efficacy of cell therapy in heart failure.                                                 The next study provides evidence that fractional flow reserve or FFR is a useful index for decision-making in real life daily cath lab practice. First author, Dr. Ahn, corresponding author, Dr. Park and colleagues from Heart Institute Asan Medical Center in South Korea, evaluated the prognosis of deferred and revascularized coronary stenosis after FFR measurement in the IRIS-FFR registry of 5,848 prospectively enrolled patients. This large prospective registry showed that the FFR was linearly associated with the risk of cardiac events in deferred lesions. In addition, revascularization for coronary artery stenosis with a low FFR of less than 0.75 was associated with better outcomes than deferral, while for a stenosis with a high FFR of greater than 0.76, medical treatment would be a reasonable and safe strategy. Thus, the authors concluded that FFR may be considered a clinical prognostic index in addition to a physiological quantification for flow-limiting stenosis. These and other issues are discussed in an accompanying editorial by Doctors De Bruyne, Fournier and Barbato.                                                 The next study sheds important insights into a potential disease modifier in pulmonary arterial hypertenstion, and that is vascular endothelial growth factor receptor three, or VEGF receptor three. First author, Dr. Hwangbo, Co-corresponding authors Dr. Chun and Dr. Jin from Yale Cardiovascular Research Center in Connecticut, used a combination of experimental animal models, human patient cells and detailed signaling studies to demonstrate the importance of a novel interaction between bone morphogenetic protein type two receptors, or BMPR2 and VEGF receptor three in regulating the robustness of endothelial bone morphogenic protein signaling response. They demonstrated that the interaction was critical for promoting BMPR2 internalization in response to bone morphogenic protein stimulation. They further showed that genetic deletion of endothelial VEGF receptor three in mice resulted in exacerbation of chronic hypoxia-induced pulmonary hypertension and impaired bone morphogenic protein signaling. Thus, these findings identify VEGF receptor three as a key regulator of endothelial BMPR2 signaling and a potential determinant of pulmonary arterial hypertension penetrance in humans.                                                 The next study tells us that a low-dose drug-coated balloon may be a promising treatment option in symptomatic superficial femoral or popliteal artery disease. Dr. Schroeder and colleagues of the Jewish Hospital in Berlin, Germany, reported results of the ILLUMENATE European Randomized Clinical Trial, which was a prospective randomized multi-center, single-blinded trial, where patients were randomized 3:1 to treatment with a low-dose drug-coated balloon or an uncoated percutaneous transluminal angioplasty balloon. The primary safety endpoint was a composite of freedom from device and procedure-related death through 30 days, and freedom from target limb major amputation and clinically-driven target lesion revascularization through 12 months. The primary effectiveness endpoint was primary patency at 12 months. The main results were that in symptomatic patients, with superficial femoral and/or proximal popliteal artery disease, low-dose, drug-coated balloon was safer and more effective than uncoated percutaneous transluminal angioplasty balloons through follow-up of 12 months. This is discussed as a novel strategy to reduce femoral popliteal restenosis in an accompanying editorial by Doctors Goldsweig and Aronow.                                                 The final study provides important genotype-phenotype correlations of SCN5A mutations in probands with Brugada syndrome. First author, Dr. Yamagata, corresponding author, Dr. Shimizu and colleagues of Nippon Medical School in Tokyo, Japan, studied 415 Japanese Brugada syndrome probands to assess the association between SCN5A mutations and clinical outcomes. During a mean follow-up period of 72 months, the overall cardiac event rate was 2.5% per year. Compared to probands without mutations, probands with SCN5A mutations experienced their first cardiac event at a younger age, had a higher positive rate of late potentials and exhibited longer P-wave, PQ and QRS durations, and had a higher rate of cardiac events, especially when the mutations were located in the pore region of the encoded protein. The conclusion was therefore, that genetic screening for SCN5A mutations among Brugada syndrome probands may be useful for stratifying such patients according to their risk of subsequent cardiac events. Well, that wraps it up for your summaries. Now for our feature discussion.                                                 Our feature paper today is the stuff that really could change guidelines. Now, we're talking about superficial femoral artery disease and its treatment. Unlike most other vascular beds, where stenting is the preferred modality of endovascular revascularization, the optimal therapy for superficial femoral artery disease remain controversial. However, today's paper really adds to our insight and I am so pleased to have the first and corresponding author Dr. Ilka Ott, from German Heart Center in Munich, as well as Dr. Manos Brilakis, Associate Editor, from UT Southwestern. Welcome both. Dr. Ilka Ott:                         Welcome. Dr. Manos Brilakis:           Morning. Dr. Carolyn Lam:               Wonderful. So Ilka could you please share what you found? Dr. Ilka Ott:                         We already know from previous studies there has been a lot of studies showing the drug-eluting balloon is superior to plain angioplasty in superficial artery disease. So then, in our study, we found that the treatment with the drug-eluting balloon plus stenting was very superior to the balloon angioplasty plus stenting and the directional atherectomy. The primary endpoint we used in the study was an angiographic endpoint. It was diameter of stenosis and this was significantly lower in the patients treated by drug-eluting balloon angioplasty, as compared to the balloon angioplasty and atherectomy group. Moreover, we had a clinical follow-up of 24 months and we found that also the target lesion revascularization was 70% in the group of drug-eluting balloon plus stent as compared to 37% in the balloon angioplasty and stent group, and 53% in the atherectomy group. We found a significant reduction also in the clinical endpoint of TLR at three years. Dr. Carolyn Lam:               Wow Ilka, congratulations, but may I just ask, was there any reason to think that a drug-eluting balloon would not be similarly beneficial as in other vascular beds? Dr. Ilka Ott:                         Well, I think is not a novelty of the study. We already know from previous studies that drug-eluting balloon is superior to plain balloon angioplasty so that's not a surprising result. However, in disease of the femoral superficial artery we often have the problems, in particular when we treat complex lesions like along occlusions or along calcified stenosis, that drug-eluting balloon is not sufficient, so you need to also stabilize the lesion to stabilize dissections. You also need to do a stent implantation. Our study now shows that the combination of drug-eluting balloon plus stent is superior than plain balloon angioplasty plus stent. The nice approach is most of the time if you need a stent, if you use drug-eluting balloon and the lesion is stable and you don't need a stent you are glad. This has shown previous studies, however, if you need further treatment and you need to place a stent, we now show that the pretreatment with a drug-eluting balloon is a superior option than just the plain balloon angioplasty. Dr. Carolyn Lam:               Manos, what is your take on these results? Do you think it will impact guidelines? Dr. Manos Brilakis:           First of all, I would like to congratulate Dr. Ott for an excellent study. I think what is particularly important here, is the comparative effectiveness component. We have several studies circulating already about drug-coated balloons, have studies on stents, but we don't have studies addressing the other modalities like atherectomy. Why I was particularly impressed, is I think the study will have a finally an assessment of atherectomy as a primary strategy for calcified lesions and it's interesting that that was not as good efficacy. It was actually tents for worse TLR as compared to plain old balloon angioplasty and stent. Would like to ask Dr. Ott what is your kind thoughts about the alone atherectomy give the results of the study? Are they still doing it or is it falling out of favor? Dr. Ilka Ott:                         Yes, I think this is a very important point. I think atherectomy alone is not an appropriate treatment but there are some data that atherectomy in combination with drug-eluting balloon gives much better results, or you may even think about a combination of atherectomy and drug-eluting stent, so it often is the case. This study also raises a lot of questions and gives some thought into further studies. I think in the combination atherectomy might still have its place. Dr. Carolyn Lam:               Could you tell us some of those plans for future studies? Dr. Ilka Ott:                         Well, we are just in the initiation phase but I think one also very interesting concept is to compare drug-eluting balloon plus stent to the drug-eluting stents that have been on the market. However, as I said before, there's again the concept if you combine the drug-eluting balloon plus a stent it might be also, from the commercial aspect, better because sometimes you don't need the stent. And then moreover, the drug-eluting stents are much more expensive. It would be interested to see a study like that. Dr. Carolyn Lam:               What about the concern that the superficial femoral artery is subject to a lot of stretching and external compression and it's long and ... Maybe I'm out of date here about the concern of stent fractures and so on. It looks like your study has disproven this, or do you think the follow-up's long enough? Dr. Ilka Ott:                         I think the follow-up of two years is quite good, but you're right, it seems like in the superficial femoral artery the restenosis process is much longer and more prolonged. Of course, you would like not to place a stent in the SSA but from the interventional aspect, it's often not possible because if you have a dissection with a limiting the flow, you have to fix that by putting in a stent. Nitinol stents are pretty good these days. Moreover, we have another generation of the woven stents the Supera stents that might also be an interesting point to investigate in comparison to the strategy we now have shown to be superior. Dr. Manos Brilakis:           I think what we need is more studies like this, that they take the other modalities like atherectomy, laser and combine them with what is currently the standard of care, which is drug-coated balloons or drug-coated balloons plus stent, as shared in the study. I just want to congratulate Dr. Ott on her study and encourage future studies from the group. I know the ISAR group is been a phenomenally productive group in coronary intervention and I'm delighted to see they're expanding on the peripheral world. Dr. Carolyn Lam:               I couldn't agree more. Congratulations, once again, for a study that really will impact practice and that we're so proud to be publishing in Circulation.                                                 Listeners, I'm sure you learned as much as me, so please don't forget to tune in next week as well. Thanks.

  Carolyn: 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. Today we will be diving deep into issues of resistant hypertension, adherence to anti-hypertensive medication, and renal denervation. All this by looking closely at new data from the Renal Denervation for Hypertension trial. First, here are your summaries of this week's journal.     The first paper sought to answer these questions: How can we better re-stratify patients with long QT syndrome type 3? You will remember that as the type caused by a gain of function mutation in the SCN5A sodium channel, and the type that has a more lethal course than types 1 and 2. Another question is, are we sure that beta blockers are effective in type 3 long QT syndrome? Well the current study is by co-first-authors, Dr. Wilde of Academic Medical Center, Amsterdam, and Dr. Moss from University of Rochester School of Medicine and Dentistry, which is the largest multi-center long QT type 3 syndrome cohort described to date.     This study was designed to identify the risk and therapeutic factors associated with cardiac events in patients. The risk factors evaluated included clinical features such as age, gender, ECG measurements, the mutation type, and the therapeutic effects of beta blockers, other medications, and ICD. In almost four hundred patients with type 3 long QT syndrome, 30% experienced at least one cardiac event; that is syncope, aborted cardiac arrest, or sudden death. The risk of a first cardiac event was directly related to the degree of QT prolongation. Each 10 millisecond increase in QTC up to 500 milliseconds was associated with a 19% increase in cardiac events. Prior syncope doubled the risk of life threatening events. Beta blocker therapy was associated with an 83% percent reduction in cardiac events in females, however the efficacy in males could not be conclusively determined due to low number of events. The take-home message is, in your patients with long QT syndrome type 3, recognize the very high risk sub-population with prolonged QTC and a history of syncope.     The next paper is a basic science paper that reveals a novel way in which mitochondrial dysfunction may be targeted in heart failure. This paper is from first author Dr. Li, corresponding author Dr. Tian, and colleagues from the Mitochondria and Metabolism Center at University of Washington. These authors previously found that elevation in the NADH to NAD ratio induces mitochondrial protein hyperacetylation, and renders hearts highly susceptible to stresses, and they showed this in a mouse model of primary mitochondrial dysfunction caused by genetic defects. In the current study they defined the molecular intermediaries linking specific NAD sensitive hyperacetylation targets to the development of heart failure, and further demonstrated the relevance of these mechanisms in human heart failure. Specifically, they identified that hyperacetylation of the regulators of mitochondrial permeability transition poor and malate-aspartate shuttle, mediates the increased susceptibility to cardiac stresses. Further, expanding the cardiac NAD pool via pharmacological or genetic approaches normalized the NADH to NAD ratio, and thereby normalized protein acetylation in hypertrophied and failing hearts. Importantly, these measures improved cardiac function and reduced pathological hypertrophy in mice. Thus, the clinical implication is that restoring the NADH to NAD ratio may be an effective and translatable strategy to treat mitochondrial dysfunction in heart failure.     The next study broadens our considerations of the benefits versus risks of intensive anti-platelet therapy in patients with a prior myocardial infarction, and really suggests that more intensive anti-platelet therapy should be considered, not only to reduce the risks of coronary events, but also to reduce the risk of stroke. This is a paper from Dr. Bonaca and colleagues of the TIMI study group from Brigham and Women's Hospital in Boston, Massachusetts, who investigated the efficacy of ticagrelor, 60 milligrams twice a day, for reducing stroke in patients with a prior myocardial infarction from the Pegasus-TIMI 54 trial.     You will remember that in the Pegasus-TIMI 54 trial, ticagrelor was already shown to reduce the risk of major adverse cardiovascular events when added to low-dose aspirin in stable patients with prior MI. Of more than 14,000 patients randomized to placebo or Ticagrelor, 213 experienced a stroke, 85% of which were ischemic. 18% of strokes were fatal, and another 15% led to either moderate or severe disability at 30 days. Ticagrelor significantly reduced the risk of stroke, with a hazards ratio of 0.75, and this was driven by a reduction in ischemic stroke. Hemorrhagic stroke occurred in nine patients on placebo and eight patients on ticagrelor. Furthermore, a meta-analysis of four placebo-controlled trials of more intensive antiplatelet therapy in more than 44,800 patients with coronary disease confirmed a marked reduction in ischemic stroke, with a combined hazards ratio of 0.66. Thus this study really broadens our considerations of benefits versus risks of intensive antiplatelet regimens for the long-term secondary prevention in patients with patients with prior myocardial infarction. It really highlights the broader benefits in reducing ischemic stroke, and not just coronary events. In summary, overall, for 1,000 patients initiated on ticagrelor 60 milligrams twice daily for three years, 13 primary endpoint events would be prevented, including approximately five ischemic strokes. This benefit would come at a cost of nine TIMI major bleeds, but no hemorrhagic strokes or fatal bleeds.     That wraps it up for our summaries! Now for our feature paper. Our feature paper today discusses a really important issue that we face everywhere around the world, and that is the management of resistant hypertension. We're taking a very interesting look at the Renal Denervation for Hypertension trial, because we're actually looking at the adherence to anti-hypertensive therapy, and what we've learned in this trial. I'm so excited because I am sitting right here with first and corresponding author Dr. Michel Azizi, from Georges Pompidou hospital in Paris, France. Hello Michel, thank you!   Michel: Hello, Carolyn. Thank you also for the invitation to discuss about the paper.   Carolyn: We're also so lucky to have the associate editor who handled the paper, Dr. Wanpen Vongpatanasin, associate editor from UT Southwestern. Welcome, Wanpen.   Wanpen: Hi, Carolyn.   Michel: Hi, Wanpen.   Carolyn: This whole issue of resistant hypertension, I'll tell you, to me that means someone who's adequately treated, and despite all the treatment that we can throw at them, they still have a blood pressure that is above a certain level, right?   Michel: Yes.   Carolyn: But your study seems to tell us that that assumption, that everyone's receiving treatment and still having high blood pressure, may need to be questioned, so please tell us a little bit more about what you found.   Michel: This is a clinical trial where we compared the effect of renal denervation to medical treatment, optimal medical treatment. We standardized the anti-hypertensive treatment in the cohort of patients with resistant hypertension, and then we followed them on a monthly basis with home blood pressure monitoring. We also increased the intensity of the treatment every month after randomization between renal denervation against nothing, because this is a probe trial, it is not a double blind trial. We gave them the same treatment in both arms. At the end of the many study we demonstrated that there was 6 millimeter of difference, in terms of ABPM, in favor of renal denervation, against the same medical treatment alone.     However, because this trial was an open trial, it was open to a Hawthorne effect, and the possibility that patients or doctors behave differently in each arm of the study. Those having renal denervation may be more adherent to the treatment, and those not being given the new therapy, not being really adherent to treatment. This was an issue, so we specified analysis. We also measured drug levels in urine after six months of followup, and also assessed the exposure to each individual using a peptide in urine, which is N-acetyl-serylaspartyl-lysyl-proline (AcSDKP)/creatinine.     What we found after six months of followup in patients who really participated to this trial, they were willing to participate to the study, they signed an informed consent where it was written that, indeed, we will monitor drug levels. They knew that we would do this. They also knew that we will follow them very carefully every month, et cetera, that we'll provide them home blood pressure monitor for free. They had access to the same doctor, same nurse, same everything. They could arrive at the time they wanted in the morning for being investigated. After six months of followup we found that more than half of these patients did not take correctly their treatment, and even 15% of them, in reality, took zero medication over seven medications. This was a major, major surprise for us in this trial.   Carolyn: I think that's one of the most significant findings, even in a trial setting, that is such a lot of non-adherents, anti-habitants, of therapy. It really makes us question when we say someone has resistant hypertension, is it really that, or do we have just a very non-compliant patient?   Michel: Yes.   Carolyn: Because it can only be worse in the real-world setting, isn't it? Congratulations, that was a very striking message to me as well. What was the other main finding that you wanted to ... ?   Michel: The other finding was that the rate of non-adherence was similar in both arms. That there was absolutely no influence of being randomized to the renal denervation group or the medical treatment group only. This means that the patients were not influenced, and other physicians behaved similarly in both arms. Because at the end you have exactly the same rate of non-adherence to treatment. This is also very important.   Carolyn: Yes, indeed. Wanpen, I was wondering what your thoughts were, and take-home messages from this paper. We definitely thought it was significant in the editorial board because you even commissioned a wonderful editorial by Dr. David Calhoun on this. What are your thoughts?   Wanpen: In the United States, using the same technique, we found as much non-adherence. I think there is a lot that we need to do and to understand what caused non-adherence. The patient should not be the only party that's to blame. I think that the doctor's as much of a culprit here to try to tease out what's the barrier to the treatment. Also, as pointed out by Dr. Calhoun, is that although the trials show improvement in blood pressure in both groups, at the end number of medications of patients in resistant hypertension, they require to take four to five drugs to get the blood pressure under control. I think this is going to be a lifelong continuing medication treatment that the physicians have to face, and to deal with the adherence problem as well. Just lastly, I think that although people believe that doing drug levels is only for research purpose, but many people don't realize that actually many drug levels for anti-hypertensive drugs actually is clinical available and can be ordered. It takes a little bit more effort to order it, but it can be done, and actually our center has been doing that already anyway.   Carolyn: Wow. I cannot say that my center has been doing that in Asia, but I really have to admit that this paper made me think about it. Especially the editorial when he highlights it, the very unique information that is provided by actually measuring the blood levels. Michel, you were nodding your head vigorously when Wanpen was saying that we should not just blame the patient. Tell me, what are your thoughts, and how does this affect your clinical practice?   Michel: I fully agree with Wanpen. We have to now integrate the fact that it's accessible, you can measure drug levels through technology, with mass spectrometry, et cetera. This is very important to integrate and to change our paradigm that we have to put in our brain. We have to monitor drug levels. Using this technology we have to establish a partnership with the patient.     I think the truth, also, is somewhere, as Wanpen said, we are also culprits. If patients do not take their treatment, okay, there may be some benefit and e have to look why they are not taking pill treatment, but also we are culprits because we don't listen to them, we don't take enough time, et cetera, et cetera. But I think patients should not be only blamed, so it opens a new possibility to discuss with the patient about the fact that we didn't find the drug in levels in their urine, et cetera.     However, taking into account that there will be this toothbrush effect, that is, "Patient, brush your teeth when you go to see the dentist," you'll take the pills when you go to see the doctor so you can be treated. This is one of the difficulties. However I think it's a new possibility to discuss with the patient of his or her difficulties in taking the pills. It gives us the opportunity to discuss, to take time with our patients.   Carolyn: It's really fascinating, you're talking from a system based in Europe. You're based in Paris.   Michel: Yes.   Carolyn: Wanpen just said that she's doing it, and she's based in the US. Do you now routinely, maybe, monitor these medication levels?   Michel: Yes, yes, yes.   Carolyn: Wow.   Michel: In the hospital we have these mass spectrometer platforms, so we have access to this, and we are working with the house authority to have the reimbursement. Because I think it's important, because if it's not reimbursed there is also a problem.   Carolyn: Of course.   Michel: We are working to see how it could be reimbursed for labs doing these measurements.   Carolyn: But this is for maybe selected resistant hypertensive patients that are difficult to ... ?   Michel: Yes, absolutely. Those very difficult to manage. I think, as a rule of thumb, that after four or five drugs given to the patient, if the patient-   Carolyn: Yeah, we should start questioning, are they taking it.   Michel: If the patients do not have secondary hypertension, we should really start questioning ourself whether they are taking or not the treatment, even if they are looking right in your eyes and telling you, "Yes, doctor, I'm taking all the pills."   Carolyn: Wanpen, how about the reimbursement issues and things like that in the United States? How are you getting it done in your institution?   Wanpen: Actually the coding for doing drug levels, it's actually generic. It's the same coding for Digoxin or Cyclosporine. They actually don't care about what the name of the drug. Strangely, they're coded by the technique, so that's how we go with it, but we have to put in miscellaneous "other" for, we wanted to test for this. That's how we get around it.   Carolyn: Do you do that again routinely, or in selected patients that are difficult to manage hypertensive?   Wanpen: Obviously we have to be selective, so we select from people who we would suspect are non-adherent, but they say they're taking it. But if they already came in and made that they're not taking the drug, there's no point doing that for the clinical purpose. We're doing it for people who we suspect it, and we use it the way ... Actually we shall describe very well, not only just to find what drug they're not taking, because when they're not taking, only about 30% are not taking everything, about 20% not taking one or two drugs. When we drill down to that drug they say, "I have side effects to beta blocker and I don't want to tell my physician that I have problems taking it, but I just not take it." I think that's what led us to pinpoint the problem a little bit better with this technique.   Carolyn: What a lot of practical advice, and congratulations once again for very, very meaningful findings. I learned a lot this time. I don't do this, and so I'm definitely going to think about this much more because of your work. Thank you very much Wanpen, Michel.     And thank you, listeners, for tuning in this time. Remember, you're listening to circulation on the run. Listen in again next week. Thanks.    

The PR interval on the electrocardiogram reflects atrial and atrioventricular nodal conduction time. The PR interval is heritable, provides important information about arrhythmia risk, and has been suggested to differ among human races. Genome-wide association (GWA) studies have identified common genetic determinants of the PR interval in individuals of European and Asian ancestry, but there is a general paucity of GWA studies in individuals of African ancestry. We performed GWA studies in African American individuals from four cohorts (n = 6,247) to identify genetic variants associated with PR interval duration. Genotyping was performed using the Affymetrix 6.0 microarray. Imputation was performed for 2.8 million single nucleotide polymorphisms (SNPs) using combined YRI and CEU HapMap phase II panels. We observed a strong signal (rs3922844) within the gene encoding the cardiac sodium channel (SCN5A) with genome-wide significant association (p < 2.5 > 10(-8)) in two of the four cohorts and in the meta-analysis. The signal explained 2% of PR interval variability in African Americans (beta = 5.1 msec per minor allele, 95% CI = 4.1-6.1, p = 3 x 10(-23)). This SNP was also associated with PR interval (beta = 2.4 msec per minor allele, 95% CI = 1.8-3.0, p = 3 x 10(-16)) in individuals of European ancestry (n = 14,042), but with a smaller effect size (p for heterogeneity < 0.001) and variability explained (0.5%). Further meta-analysis of the four cohorts identified genome-wide significant associations with SNPs in SCN10A (rs6798015), MEIS1 (rs10865355), and TBX5 (rs7312625) that were highly correlated with SNPs identified in European and Asian GWA studies. African ancestry was associated with increased PR duration (13.3 msec, p = 0.009) in one but not the other three cohorts. Our findings demonstrate the relevance of common variants to African Americans at four loci previously associated with PR interval in European and Asian samples and identify an association signal at one of these loci that is more strongly associated with PR interval in African Americans than in Europeans.