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Welcome to EP Edge Journal Watch — where cardiac electrophysiology meets evidence, precision, and perspective.
Hosted by Dr. Niraj Sharma, this bi-weekly podcast distills high-impact cardiovascular and EP 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
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
Welcome back to EP Edge Journal Watch. I am Doctor. Sharma and thank you for joining me. In this issue we are covering one of the most important tensions in contemporary electrophysiology. When is a signal just noise and when is it something we really need to pay attention to?
Niraj Sharma:We will look at early recurrence after pulsed field ablation, whether PFA is truly outperforming thermal ablation, and what untreated non pulmonary vein triggers may be costing us after a first atrial fibrillation ablation. As we move through this issue, keep this broader theme in mind. EP is increasingly about precision, not just procedure. Let us start with the first study on early recurrence after pulse field ablation for paroxysmal atrial fibrillation. Traditionally, we have all been trained to think of the first three months after ablation as a blanking period, meaning early atrial arrhythmias may reflect transient inflammation, edema, or lesion maturation rather than durable failure.
Niraj Sharma:But this study raises a major question: does that old thermal era assumption fully apply to PFA? In this prospective single center study, patients underwent PFA pulmonary vein isolation and then had continuous rhythm monitoring with implantable loop recorders. That is important because continuous monitoring gives us a much more sensitive view of recurrence than routine clinical follow-up. What they found was striking. About thirty eight percent of patients had early recurrence, and every one of those patients later went on to have late recurrence.
Niraj Sharma:Now, the nuance matters. This was a small cohort and overall arrhythmia burden remained very low. So this is not a paper telling us to panic over every brief episode, but it is telling us that after PFA, early recurrence may be a much cleaner signal than we used to think. In practical terms, if a patient has recurrent atrial arrhythmia early after PFA, especially beyond the first few weeks, that should trigger closer surveillance and more mechanistic thinking. Is this pulmonary vein reconnection?
Niraj Sharma:Is this nonpulmonary vein substrate? Is this a different atrial tachyarrhythmia phenotype emerging? That is the new conversation. Next is the Bayesian meta analysis comparing pulsed field ablation with thermal ablation. This is an especially useful paper because it does not just ask whether there is a statistically significant difference, it asks how probable it is that PFA is actually better.
Niraj Sharma:Let me briefly explain Bayesian statistics in practical language. In traditional frequentist statistics, we often ask, If there were truly no difference, how likely would it be to see the data we observed? That leads us to p values. Bayesian analysis asks a more clinically intuitive question: Given the data we now have, what is the probability that one treatment is better than the other? That is often closer to how clinicians actually think.
Niraj Sharma:In this meta analysis, PFA appeared associated with better freedom from arrhythmia recurrence, shorter procedure time, and shorter left atrial dwell time. Safety overall looked favorable and there was no major harm signal. But here is the most important nuance: the probability of clinically meaningful benefit was much stronger in observational studies than in randomized trials. That gap is the warning label. It tells us that some of the apparent superiority of PFA may be inflated by selection bias, workflow bias, or non randomized comparisons.
Niraj Sharma:So what is the real take home? In 2026, the strongest case for PFA remains efficiency, reproducibility, and a favorable safety profile. Superiority in efficacy is plausible, maybe even likely in some settings, but it is not yet fully proved across all atrial fibrillation phenotypes. That is the intellectually honest position. The third study examines the role of non pulmonary vein triggers in first time AF ablation.
Niraj Sharma:This is highly relevant because many of us have wrestled with the same question. When you find a non PV trigger, are you identifying a truly actionable driver of recurrence or are you simply revealing a more diseased atrium? In this large prospective registry from Penn, most patients had no non PV triggers. Some had triggers that were mapped and ablated. A very small group had reproducible non PV triggers that were not treated or could not be successfully ablated.
Niraj Sharma:And that last group did terribly. Their recurrence rate was over seventy percent at one year. That is the key message. Untreated reproducible non PV triggers are not benign background noise. They appear to carry a major recurrence penalty.
Niraj Sharma:Now that does not mean we should chase every fleeting provoked ectopic beat with aggressive lesion sets, but if you identify a convincing, reproducible, clinically plausible trigger, leaving it untreated is usually not neutral and that is a very important distinction for procedural strategy. In the next segment, we will move into Class Ic antiarrhythmic therapy after PCI, device reliability warnings, and early data on the next generation Amulet three sixty platform. Let us continue with the provocative reappraisal of Class Ic antiarrhythmic therapy after PCI in patients with new onset atrial fibrillation. Ever since cast, class Ic drugs such as flecainide and propafenone have carried a strong stigma in the setting of coronary disease, and for good reason. Cast showed proarrhythmic risk in a very different era in a very different substrate, but modern PCI patients with revascularized disease and preserved ventricular function are not necessarily the same population.
Niraj Sharma:This nationwide cohort study suggested that selected class Ic users after PCI did not have more ventricular arrhythmias and in fact appeared to have lower rates of major adverse cardiovascular events, mortality, and cerebrovascular events. Now before anyone overreacts, this is not a paper that vindicates class Ic therapy across the board. The magnitude of apparent benefit is too large to accept uncritically. This almost certainly reflects physician selection of lower risk patients, but the study still matters. It pushes back against lazy, absolute extrapolation of cast to every patient with any history of coronary artery disease.
Niraj Sharma:The right takeaway is narrower: blanket prohibition may be too simplistic, but blanket rehabilitation is also unjustified. The real question is whether there is a selected subgroup, revascularized, preserved ejection fraction, minimal scar burden, low ischemic risk, where class Ic therapy may be reasonable. That is exactly the population that deserves randomized study. The fifth paper is one of those studies that may change device clinic behavior immediately. It focuses on rapid early battery depletion and lead electrode corrosion caused by gate oxide semiconductor defects in cardiac implantable electronic devices.
Niraj Sharma:Here is why this matters: When a newly implanted pacemaker or defibrillator shows rapid battery depletion, abnormal lead impedance, loss of telemetry, or bizarre diagnostics that do not make physiologic sense, our first instinct is often to blame the lead, but this paper tells us there is another important possibility. The problem may actually be the pulse generator itself, specifically a semiconductor defect causing high current drain and secondary lead damage. The timing was notable with many failures occurring within the first year and pacemakers failing earlier than ICD's clinical consequences were not trivial. They included syncope, heart failure, cardiac arrest and even death. This is not a paper that gives us true incidence because MOD is a passive reporting system, but it absolutely gives us a pattern to recognize.
Niraj Sharma:If the device story stops making physiologic sense, especially early after implant, generator failure should move up the differential. The sixth study gives us early outcomes with the next generation Amulet three sixty dual seal left atrial appendage occluder. We all know the broader challenge in this space. Device closure performance can look excellent, but the clinically meaningful endpoint is long term stroke prevention without forcing patients back onto chronic anticoagulation. In Veritas, implant success was nearly universal.
Niraj Sharma:Complete closure rates at forty five days were excellent. There was no leak greater than three millimeters, device embolization was zero, and pericardial effusion requiring intervention was low. Those are very encouraging engineering and procedural signals. But there is an important caution here. This was a single arm short term device performance study.
Niraj Sharma:It tells us that the redesign appears promising. It does not yet prove long term stroke reduction superiority or even equivalence against alternative strategies. One especially important detail was the difference between site reported and core lab detected device related thrombus. That discrepancy reminds us that adjudicated data can be more sobering than operator impression. So the practical position today is this: Amulet three sixty looks technically impressive and procedurally encouraging, but the long term clinical proof is still maturing.
Niraj Sharma:In the next segment, we turn to a fascinating bench safety paper on pulsed field ablation near appendage occlusion devices, a very practical paper on activated clotting time variability, and an athlete cardiology study that reframes sinus bradycardia through both physiologic and genetic lenses. The seventh study is a bench investigation but clinically it has outsized relevance. It examined pulsed field ablation near metallic left atrial appendage occlusion devices such as Watchman and Amulet. Why does this matter? Because as combined or sequential AF ablation and appendage occlusion strategies become more common, we need to understand whether PFA behaves safely near metallic structures.
Niraj Sharma:In this in vitro model, when PFA electrodes were in direct contact with, or extremely close to, the occlusion device, arcing occurred, generators frequently interrupted or prevented energy delivery, and when lesions were created in that setting, they were often irregular and shallower. At about three millimeters of separation, those problems disappeared. That is the operational message. This is not philosophical. It is spatial.
Niraj Sharma:Do not allow PFA electrodes to work in direct contact or near contact with a netanol appendage device. If you are too close, you may not only interrupt delivery, you may also create distorted incomplete lesions and potentially increase local risk. So when ablating near a prior appendage occluder, intentional distance matters. The eighth paper addresses something every EP lab should care about more than it probably does: activated clotting time platform variability during left atrial ablation. We often say things like target an ACT above three hundred seconds as though that number means the same thing everywhere.
Niraj Sharma:This paper strongly suggests it does not. The authors reviewed the limited direct comparison literature and paired that with an international physician survey. What they found was that ACT values measured simultaneously on different platforms can differ by fifty-sixty seconds. That is not trivial. A lab targeting 300 on one machine may be functionally anticoagulating very differently from a lab targeting 300 on another.
Niraj Sharma:In the real world, this matters because physicians do adapt their heparin strategy based on the platform they use. Higher targets and larger heparin doses were more common with some platforms, lower with others. Nearly one third of respondents said they changed their dosing approach after changing ACT systems. The clinical takeaway is uncomfortable but important. A universal ACT threshold may be partly a myth.
Niraj Sharma:In the PFA era, where procedures can be shorter and decisions may hinge on only a few ACT checks, platform awareness becomes even more important. We should not just be target aware, we should be platform aware. The ninth study turns to athlete bradycardia and this paper is especially useful because it helps separate what is unusual from what is dangerous. In elite endurance athletes, low resting and minimum heart rates are common. But when those rates become very low, clinicians naturally wonder, is this still physiologic or are we drifting into sinus node disease?
Niraj Sharma:In this cohort of current and former elite endurance athletes, minimum heart rates of 40 bpm or less were common. Two-three second pauses occurred with some frequency. Yet clinically important adverse events were rare and among those with very low heart rates, there was no clear short term signal of syncope, pacemaker implantation, or other major downstream harm. What makes this paper especially interesting is the genetic angle. A lower heart rate polygenic risk score was associated with greater bradycardic burden.
Niraj Sharma:In other words, athlete bradycardia may not be purely a training effect. It may reflect a combination of training adaptation, remodeling, and inherited predisposition. The clinical message is reassuring but not careless. We should avoid overmedicalizing asymptomatic athlete bradycardia, especially when the phenotype is otherwise typical. But we still need a bright line around symptoms, structural heart disease, Mobitz type II block, and complete AV block.
Niraj Sharma:Those are not training effects. In the final segment, we will cover two clinically relevant studies on diltiazem and factor Xa inhibitors, then close with a broader synthesis on stroke prevention after AF ablation through the lens of OCEAN alone AF an option. Let us move now to one of the most practical prescribing issues in everyday atrial fibrillation diltiazem, combined with factor Xa inhibitors. Diltiazem is often treated as a routine, almost casual rate control drug, but pharmacologically it is not neutral. It can inhibit CYP3A4 and P glycoprotein, increasing exposure to these anticoagulants and potentially increasing bleeding risk.
Niraj Sharma:What makes this issue especially important is that we now have two complementary cohort studies pointing in the same direction. The earlier study showed that concomitant diltiazem was associated with more bleeding related hospitalization and more major bleeding compared with factor Xa inhibitors used without diltiazem. The newer study used a stronger active comparator, comparing diltiazem directly with metoprolol in patients on ipixaban or rivaroxaban. Again diltiazem came out with a higher bleeding signal and importantly the risk was greater at higher diltiazem doses. Now the absolute excess risk for an individual patient is not massive, but the consistency of the signal matters, and the dose response pattern makes the interaction biologically and clinically more believable.
Niraj Sharma:So the practical takeaway is this: diltiazem is no longer a benign default partner for apixaban or rivaroxaban. If beta blockade is reasonable, metoprolol increasingly looks like the cleaner default. And if diltiazem must be used, especially at higher doses, it deserves more deliberate bleeding surveillance. The final paper is a perspective that synthesizes three important post ablation stroke prevention trials: OCEAN, ALONE, AF, and OPTION. This is a major issue because one of the biggest unresolved questions in modern AF care is what to do with stroke prevention after apparently successful ablation.
Niraj Sharma:Current guidelines remain appropriately conservative. If stroke risk is moderate to high, anticoagulation is generally continued regardless of procedural success, and there are good reasons for that. Silent AF recurrence can occur, atrial cardiomyopathy can persist, and stroke biology is not erased simply because the rhythm looks better. But what these trials collectively suggest is that the future may be more individualized and more phenotype driven. Ocean suggested that thromboembolic event rates after successful ablation were very low, while bleeding remained relevant with continued rivaroxaban.
Niraj Sharma:Alone AF suggested that in carefully selected patients without documented recurrence, stopping oral anticoagulation may reduce the composite of embolic and bleeding events, largely because of less major bleeding. Option then added another dimension. If you mechanically exclude the appendage with left atrial appendage occlusion, you may preserve stroke protection while reducing non procedural bleeding compared with continued anticoagulation therapy. To me, the most important conceptual advance here is that rhythm control, substrate risk, and stroke prevention are related, but they are not interchangeable. A successful ablation does not automatically erase embolic biology, and a closed appendage does not improve rhythm outcomes.
Niraj Sharma:These are different axes of care. So where does that leave us in practice? Not with dogma, not with reflex continuation of anticoagulation in everyone, and not with reflex discontinuation after every apparently successful ablation. It leaves us with a more individualized model based on CHADS VASc score, bleeding liability, recurrent AF burden, atrial substrate, and whether the appendage has been mechanically excluded. Patients with low CHADS VASc score less than three with rigorous AF monitoring along with excellent AF phenotype may be considered for cautious withdrawal of anticoagulation that is where the field is heading.
Niraj Sharma:And that brings us to the end of this issue of EP Edge Journal Watch. Thank you again for listening. I truly appreciate your time and your continued support. Full references and infographics are available on the LinkedIn newsletter, EP Edge Journal Watch and also on Substack. If you have questions, comments or suggestions for future issues, you can reach me at epedgecastgmail. com.
Niraj Sharma:Thank you again for being here. Thank you for following and please continue to follow, share and support EP Edge as we keep building this community together. Until next time, take care.