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Welcome to EP Edge Journal Watch, where cardiac electrophysiology meets evidence, precision, and perspective.
Hosted by Dr. Niraj Sharma, this weekly podcast distills high-impact cardiovascular and Cardiac Electrophysiology and arrhythmia research into clear, clinically meaningful insights. Each episode goes beyond headlines and abstracts to uncover what new studies actually mean for patient care, decision-making, and the future of electrophysiology.
What EP Edge Journal Watch stands for:
Evidence-based practice
Precision electrophysiology, arrhythmias analysis
A forward-thinking, edge-driven approach to how we interpret and apply data in real-world clinical settings.
Whether you’re an electrophysiologist, cardiologist, researcher, trainee, or allied health professional, EP Edge Journal Watch brings you the signal not the noise. Expect sharp summaries, thoughtful commentary, and practical takeaways designed for the busy clinician who wants to stay ahead of the curve
This program is for educational purposes only and reflects independent editorial commentary. It is not medical advice and should not replace clinical judgment or review of primary sources and guidelines. The views expressed are those of the host and contributors.
Niraj Sharma:Hello and welcome to epedge Journal Watch. I'm Doctor. Sharma. Thank you for joining us for Issue 44, November 2026. Today, we are examining five papers in-depth.
Niraj Sharma:We begin with Wong's recommendations for measuring atrial fibrillation ablation outcomes followed by Andrade's analysis of shorter trial follow-up. We then consider Varma's combined pacing and defibrillation strategy, LIMS assessment of atrial disease in hypertrophic cardiomyopathy, and Wei's study of physical activity intensity. For each, we'll work through the clinical question, the approach, the findings, and what they mean for practice. We'll also briefly cover the remaining publications. The newsletter contains the complete assessments and infographics.
Niraj Sharma:Paul Wang et al. Paper is Ablation, Effectiveness Endpoints, safety endpoints, and trial design, academic research consortium initiative endorsed by the Heart Rhythm Society. It appeared in Circulation, Arrhythmia, and Electrophysiology in October 2026. Why was this needed? Ablation technologies have evolved but trials still differ in recurrence definitions, monitoring, drug withdrawal, and safety reporting.
Niraj Sharma:A thirty second recurrence can label treatment a failure despite substantial symptomatic improvement. Conversely, sparse monitoring can label treatment a success while missing recurrent disease. New energy sources also bring safety questions that older protocols may not adequately address. The consortium's purpose was to establish a common framework for evaluating effectiveness and harm. Three international working groups addressed effectiveness, safety and trial design, with regulatory, clinical, patient and industry participation.
Niraj Sharma:This is an evidence informed consensus, not a randomized test of its recommendations. The framework starts with when recurrence should count. Early arrhythmias may reflect transient inflammation and autonomic changes, rather than durable treatment failure, however excluding too much early follow-up can conceal meaningful recurrence. The recommended blanking period is therefore two months instead of three. Much of the rationale comes from thermal ablation evidence showing resolution of transient changes and greater prognostic importance of later recurrences.
Niraj Sharma:Pulsed field lesions may mature differently, but that doesn't establish a validated shorter blanking period specifically for pulsed field ablation. The next question is what recurrence should count. The proposed threshold is at least six minutes of atrial fibrillation, flutter, or atrial tachycardia on a device capable of continuous recording for that duration. Why six minutes? The report cites implantable monitor studies supporting better detection accuracy at that threshold, together with ablation sub analyses showing relatively similar recurrence rates using thirty second and six minute definitions.
Niraj Sharma:It also questions whether very brief episodes adequately represent clinical benefit. Stroke risk studies provide context but their results vary. They don't establish six minutes as a universal biological boundary or an automatic indication for anticoagulation. The authors still recommend reporting thirty second recurrences so that historical comparisons remain possible. The six minute proposal becomes clearer when we separate device detection from a trial endpoint.
Niraj Sharma:The report describes different recording capabilities. An implantable cardiac monitor may use a two minute detection window, while a pacemaker or defibrillator with atrial sensing can record shorter episodes. Those technical capabilities don't, by themselves, determine what should count as trial failure. Device alerts also require reliable rhythm classification. Programming affects false positive alerts, and systems differ in their ability to recognize regular atrial tachycardia and flutter.
Niraj Sharma:Finding more episodes is useful only if we know what was recorded and apply the same rules across comparison groups. There is an important exception to the duration rule. Any atrial fibrillation, flutter, or atrial tachycardia documented on a standard twelve lead electrocardiogram counts as recurrence. A brief clinical tracing cannot be treated as though it were a continuous recording. The report then considers burden.
Niraj Sharma:How much of the monitored time is spent in arrhythmia? This can describe substantial improvement that a first recurrence endpoint misses. A burden below zero point one percent is proposed as success with continuous monitoring. An equivalent threshold for intermittent monitoring remains unresolved and burden isn't sufficiently validated as an unrestricted, standalone primary endpoint. A low percentage can still contain a long individual episode.
Niraj Sharma:The report gives the example of six hours of arrhythmia across six months, which remains below zero point one percent. Reporting the longest episode can therefore add information that the average burden conceals. For intermittent surveillance, the recommended minimum includes three fourteen day recordings, weekly transmissions or equivalent recordings, and recordings during symptoms and visits. Monitoring adherence must also be reported otherwise, apparently better success could simply reflect less observation. Rhythm control is only one part of the primary composite endpoint.
Niraj Sharma:Freedom from cardioversion, repeat ablation, and class I or III antiarrhythmic treatment beyond blanking must also be considered. Drug washout matters because residual antiarrhythmic effects can persist after withdrawal and obscure the contribution of ablation itself. Follow-up depends on the population and technology. Established technologies in paroxysmal atrial fibrillation require at least eight months in total, two months of blanking, and six months of subsequent observation. Persistent atrial fibrillation and novel technologies require twelve months, with longer post approval observation for new technologies extending to thirty six months.
Niraj Sharma:Safety assessment must address the energy source. For pulsed field ablation, relevant concerns include hemolysis, renal injury, coronary spasm, and cerebral injury. Remapping substudies at approximately three months can assess durability and myocardial injury with novel devices or energies. The epedge take: These recommendations could make future trials more comparable, provided recurrence definitions, monitoring, medication rules, and safety surveillance are specified together. Changing one threshold alone doesn't improve the evidence.
Niraj Sharma:The proposals still need validation against patient important outcomes. No funding was reported, although many contributors disclosed industry relationships. For clinical care, a research definition must remain alongside symptoms, function, treatment burden, and the patient's priorities. The next paper tests whether the observation period itself can be shortened. Jason Andrade and colleagues published incorporating a shortened long term effectiveness endpoint into catheter ablation trials: Statistical Properties and Implications in Arrhythmia and Electrophysiology in October 2026.
Niraj Sharma:The rationale is that many failures occur relatively early after blanking. Waiting a full year increases trial cost and delays completion. But efficiency is worthwhile only if the shorter endpoint preserves enough information. The investigators pooled nine zero five patients from four prospective studies of drug refractory paroxysmal atrial fibrillation. These were per protocol populations with intermittent rhythm monitoring.
Niraj Sharma:They compared the conventional twelve month assessment, including three months of blanking, with six months in total including two months of blanking. This changes both when failures begin to count and how long investigators look for them. There were two distinct questions: whether individual patients received the same classification and whether the overall twelve month success rate could be predicted. For individual classification, agreement ranged from eighty three percent to ninety two percent. However, sensitivity for identifying conventional failures ranged from fifty seven percent to seventy six percent.
Niraj Sharma:In other words, the shortened definition missed twenty four to forty three percent of the patients classified as failures by the conventional definition. Those percentages refer to failures, not to everyone treated. High agreement can coexist with this limitation because most patients are classified as successes. Agreement alone, therefore, doesn't establish that the endpoints are interchangeable. For aggregate prediction, the investigators extended the decline in event free survival observed between months five and six.
Niraj Sharma:Predicted twelve month success was seventy two point five percent, observed success was seventy one percent. The over prediction was 1.5 points. That is encouraging but extrapolation assumes that the later trajectory resembles the earlier slope. A close population estimate doesn't ensure correct classification of individual patients or performance in a different clinical population. The proposed six month performance goal was fifty six point two percent, replacing a historical twelve month benchmark of fifty percent.
Niraj Sharma:Raising the benchmark recognizes that success is easier to achieve with less observation. It remains a single arm performance goal, not a randomized comparison. The principal limitations are intermittent monitoring, selected paroxysmal atrial fib populations, and the need for independent prospective validation. The manufacturer funded the analysis and two authors were employees. Separate supplementary analyses weren't available for independent review.
Niraj Sharma:The epedge take: This is a plausible way to make selected trials more efficient with the endpoint and benchmarks specified in advance. It doesn't justify ending patient or safety follow-up at six months. Crucially, Andrade's six months includes blanking, Wang's eight months includes two months of blanking, followed by six months of observation. The proposals are related but they are not the same. Our next question concerns the hardware used to deliver resynchronization.
Niraj Sharma:Varma and colleagues report cardiac resynchronization therapy using a conduction system pacing defibrillation lead in patients meeting CRTD indications, six month clinical outcomes results from the ASCEND CSP study. This is a 2026 article in press in JAK, Clinical Electrophysiology. Some patients have limited improvement with conventional biventricular pacing. Recruiting the native conduction system offers another route to ventricular activation, but patients who also need a defibrillator require dependable sensing and shock delivery. This study evaluates a purpose built lead intended to combine those functions.
Niraj Sharma:Before claiming a clinical advantage, we need to establish whether the lead can be implanted, captures the intended tissue, and performs reliably. Fifty two patients underwent attempted implantation. Fifty one received the investigational lead. Mean ejection fraction was approximately 29.5% and about twothree had left bundle branch block. The configuration is essential to interpretation.
Niraj Sharma:Patients received the conduction system pacing defibrillation lead together with the coronary sinus left ventricular lead. This was left bundle branch optimized resynchronization, not a test of conduction system pacing alone. Implant success was ninety eight point one percent. However, confirmed or likely left, bundle branch capture occurred in forty two of fifty one patients. The remaining nine had left ventricular septal capture.
Niraj Sharma:Anatomical placement and conduction system capture aren't interchangeable. At six months, forty nine of 50 evaluable leads met the combined sensing and threshold criteria. Defibrillation testing successfully terminated induced arrhythmias in all twenty five tested patients. That establishes encouraging performance in those tested, not universal or long term shock reliability. Estimated freedom from lead related serious adverse device effects was ninety eight point one percent, with a 95% confidence interval from eighty seven point one percent to ninety nine point seven percent.
Niraj Sharma:The width reflects substantial uncertainty from a small cohort: one mechanical lead malfunction and three septal perforations occurred during implantation. The perforations were managed without reported sequelae. One patient died before three months, with the death judged unrelated to the device or procedure. The clinical findings were also encouraging. Among thirty eight patients with paired echocardiograms, ejection fraction increased by 10.4 percentage points.
Niraj Sharma:This is an absolute change in ejection fraction, not a relative percentage increase, and it applies to patients with paired measurements. The next question is whether that improvement was greater than we would expect with conventional resynchronization. The investigators explored that question by matching 51 study patients to two zero four conventional biventricular resynchronization recipients from an earlier study. Ejection fraction increased by 10.4 versus 4.6 percentage points, with a p value of 0.0005. Clinical composite improvement occurred in seventy six point five versus fifty two percent.
Niraj Sharma:However, the heart failure quality of life improvement was similar without a demonstrated comparative advantage. Propensity matching balances selected measured characteristics. It cannot recreate randomization, remove unmeasured differences between studies, or guarantee comparable imaging and medical care. Baseline QRS duration and end systolic volume weren't included in the match and echocardiographic assessment differed. Most patients received beta blockers and other heart failure treatment.
Niraj Sharma:Medication changes, discretionary programming, missing paired imaging, and the additional coronary sinus lead complicate attribution of benefit. Multiple exploratory comparisons were not adjusted and follow-up lasted only six months. The manufacturer sponsored the study. The epedge take: Feasibility and electrical performance justify further investigation. The historical comparison suggests a potential clinical advantage but doesn't establish superiority, nor does it show that the coronary sinus lead can be omitted.
Niraj Sharma:Randomized contemporary comparisons should assess verified capture, ventricular remodeling, heart failure events, patient experience, and long term lead and shock performance. We now move from ventricular activation to atrial vulnerability. Lim and colleagues published physiological left atrial staging and the risk of new onset atrial fibrillation in hypertrophic cardiomyopathy in JAK in October 2026. The rationale is that atrial size alone may miss important functional disease. Against a stiff ventricle, the atrium can initially compensate by contracting harder.
Niraj Sharma:Later, that compensation may fail. The same strain measurement therefore needs to be interpreted in relation to loading conditions. The investigators combined estimated atrial pressure with contractile strain. Stage one represented normal pressure and function. Stage two represented relatively augmented contraction for the prevailing pressure.
Niraj Sharma:Stage III represented loss of that augmentation despite elevated pressure. Stage IV combined elevated pressure with contraction below the normal range. Isolated contractile dysfunction without elevated pressure remained a separate category. This was a retrospective prognostic study. Seven zero five of eighteen fifty six screened patients entered the main analysis, with four twenty five in an external validation cohort, prior atrial fibrillation, substantial valve disease, ejection fraction below 65%, and missing measurements were among the exclusions.
Niraj Sharma:Pressure was estimated from echocardiographic measures, including septal EE', tricuspid regurgitation velocity, and reservoir strain. Contractile strain was assessed against age and sex based normal values. A ratio derived from the study data helped distinguish compensation from loss of compensation. Over median follow-up of seven point five years, one hundred and one patients developed clinically meaningful atrial fibrillation. Estimated ten year incidence increased across the four stages: four point eight, sixteen point seven, twenty three point nine, and forty nine point one percent.
Niraj Sharma:These are time to event estimates. Only sixteen stage IV patients remained at risk at ten years, so the late figure has considerable uncertainty. Each stage increment was associated with an adjusted hazard ratio of 1.83, with a 95% confidence interval from 1.42 to 2.37. External validation produced a similar estimate of 1.82. A hazard ratio compares event rates during follow-up, not absolute percentage point differences in risk.
Niraj Sharma:Adding staging increased the clinical model's C statistic from 0.765 to 0.791, with a p value of 0.049. This measures improved discrimination between patients who develop the outcome and those who don't. It doesn't demonstrate improved outcomes from using the model. Chan and Rakowski's accompanying editorial, Atrial Cardiomyopathy and From Compensation to Atrial Fibrillation reinforces the physiological lesson: Stronger contraction can signify compensatory effort rather than a healthier atrium. Referral center selection, indirect pressure estimates, and non uniform rhythm surveillance limit generalization.
Niraj Sharma:Brief incidental episodes without subsequent treatment were excluded. Censoring at interventions that change atrial mechanics may also affect interpretation. The EP EDGE take: Atrial physiology adds useful prognostic information beyond chamber size. Stage based monitoring schedules and treatment thresholds still need prospective testing. These findings don't establish an indication for anticoagulation solely on atrial stage.
Niraj Sharma:The next step is to determine whether acting on this information improves detection and patient outcomes. Our final detailed paper asks whether exercise intensity is associated with the development of atrial fibrillation beyond the total amount of activity. Wei et al. Report volume versus intensity of physical activity and risk of cardiovascular and non cardiovascular chronic diseases, published online in the European Heart Journal in March 2026. The question is whether people with similar activity volumes have different AF risks because their intensity mix differs.
Niraj Sharma:The prospective United Kingdom biobank analysis included ninety six thousand four hundred and eight people with approximately seven days of wrist accelerometer measurement. Vigorous activity was expressed as a proportion of total activity volume weighted by metabolic equivalence including light activity. 4% on this scale is not 4% of exercise minutes and cannot be translated directly into a prescription. Over approximately nine years, 4,123 participants developed atrial fibrillation, compared with no vigorous contribution (a contribution above four percent was associated with a twenty nine percent lower relative hazard in initial adjusted model. After additional adjustment for medications, blood pressure, body mass index, biomarkers, and frailty, the association weakened to about seventeen percent.
Niraj Sharma:The hazard ratio was 0.833, with a 95% confidence interval from 0.737 to 0.940. This remains statistically significant, but it is in association with new onset atrial fibrillation, not proof that vigorous exercise prevents it. Nor did the study establish reduced recurrence after ablation, lower burden in established atrial fibrillation, or protection against ventricular arrhythmias. The relationship also wasn't indefinitely linear. The lower AF risk tended to plateau around a vigorous contribution of four-five percent.
Niraj Sharma:This general population finding cannot establish the effects of very high endurance training volumes or define a safe upper limit for athletes. What happened to the other diseases? Using the same above four percent comparison and the more extensively adjusted model, relative hazards were approximately twenty two percent lower for major cardiovascular events, defined here as myocardial infarction, stroke, or heart failure, forty percent lower for type two diabetes, and sixty percent lower for dementia. Lower hazards were also observed for immune mediated inflammatory disease, metabolic dysfunction associated steatotic liver disease, chronic respiratory disease, and chronic kidney disease, ranging from approximately twenty four percent to thirty six percent. All cause mortality was about forty percent lower.
Niraj Sharma:These are relative associations, not absolute benefits or proven treatment effects. For diabetes, liver disease, and kidney disease, both activity volume and intensity appeared relevant. The results don't justify replacing adequate overall activity with a small amount of vigorous exercise. Multiple testing adjustments limited false discoveries across outcomes. It cannot remove confounding.
Niraj Sharma:Healthier people may exercise harder and illness may reduce activity before diagnosis. One week of measurement may also poorly represent long term habits. Schwendinger et al. Accompanying editorial emphasizes individual capacity. The same workload may be vigorous for a frail older adult and modest for someone fitter.
Niraj Sharma:The epedge take for AF prevention discussions consider both activity amount and intensity within the patient's fitness and disease context. The findings support further testing of the activity mix, not a universal intensity target. For patients with established arrhythmias, this paper doesn't establish an exercise treatment regimen that requires intervention studies measuring rhythm burden, symptoms, and clinical outcomes. Let's turn briefly to the remaining publications. Each has a full assessment in the newsletter.
Niraj Sharma:Bunch and colleagues' October Heart Rhythm Commentary, The Indispensable Role of Sham Controls in Evaluating Interventional Therapies, asks how much symptomatic improvement reflects the procedure itself, rather than expectations or additional care. Its contribution is to distinguish objectively measured rhythm improvement from patient reported benefit, with the need for a sham control determined by the clinical question and ethical balance. Benato et al. Examined recurrent arrhythmias and lesion assessment after pulsed field ablation. Among one hundred and forty five patients returning for repeat procedures, all four veins remained isolated in forty two percent.
Niraj Sharma:The practical lesson is to map the mechanism of recurrence rather than assume reconnection, while recognizing that selected redo patients cannot establish durability in the full treated population. Yagishita et al. Assessed the learning curve for pentaspline pulsed field ablation with posterior wall isolation. Residual gaps became less frequent with experience and could be addressed after mapping. But the study doesn't establish a universal 20 case competency threshold or justify posterior wall isolation for every patient with persistent atrial fibrillation.
Niraj Sharma:Takase et al. Research letter addresses silent cerebral lesion burden across pulsed field ablation platforms. Lesion counts differed while binary positivity did not differ significantly, supporting more detailed safety reporting. The small, non randomized groups and procedural differences prevent reliable platform ranking. Tamiraj and colleagues discuss subcutaneous and extravascular defibrillators in relation to breast surgery, pregnancy, lactation, radiation therapy, and imaging.
Niraj Sharma:Their practical framework brings pocket position, clothing comfort, reconstruction plans, and multidisciplinary coordination into device selection without establishing one universally preferable system. Maligay Reddy et al. Review testosterone and testosterone replacement in relation to atrial fibrillation. The proposed mechanisms and nonlinear risk pattern remain uncertain. The review supports considering relevant hormone exposure in the clinical history but doesn't establish a testosterone target for arrhythmia prevention.
Niraj Sharma:Gautam Sharma et al. VPC Yoga study randomized one hundred and thirty four patients to Yoga plus standard care or standard care alone. The twelve week adjusted ectopic burden comparison favored yoga, but baseline imbalance, missing data, short rhythm follow-up, and an unblinded intervention limit. The conclusion: Improved ventricular function wasn't demonstrated. These brief reports raise useful questions about measurement mechanism and the patient's experience.
Niraj Sharma:Their full methodological assessments, limitations, and epedge takes are in the newsletter. Before we close, let's bring the five featured discussions together. Wong's consensus asks us to define ablation success through recurrence, burden, additional treatment, and adequate surveillance. Andrade tests the efficiency of shorter follow-up while showing why population agreement and individual failure detection are different questions. Varma demonstrates a promising combined pacing and defibrillation configuration, with comparative clinical benefits still requiring randomized evidence.
Niraj Sharma:Limb shows how atrial pressure and function can refine risk assessment in hypertrophic cardiomyopathy. Whey links the intensity mix of activity with future disease, while leaving the effects of an exercise prescription unproven. For each paper, the useful conclusion is the one its methods can support. A research threshold, a prognostic association, and a treatment effect should each inform care in different ways. You'll find the full newsletter, infographics, references, and article links on LinkedIn and at epedge.substack.com.
Niraj Sharma:Thank you for listening and for sharing these discussions with colleagues. Questions, suggestions, or concerns can be emailed to epedgeCast@gmail.com. I'm Doctor. Sharma.
Niraj Sharma:Thank you for listening to EP Edge Journal Watch. Take care and bye for now.