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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. This is Doctor. Sharma. Thank you for joining us for Issue 41, October 2026, An ablation endpoint, a monitoring result, and a clinical benefit are related, but they aren't interchangeable. That distinction connects our four featured papers: low voltage ablation and persistent atrial fibrillation, coronary changes after isthmus ablation, smartwatch assessment of arrhythmia burden, and appendage closure versus anticoagulation.
Niraj Sharma:We'll follow the decision from choosing a lesion set, through assessing harm and measuring recurrence, to deciding how best to prevent stroke. The remaining eight articles will receive shorter discussions. Our emphasis is on the methods and uncertainties that change interpretation in electrophysiology practice. We begin with Sohai Virk and colleagues adjunctive low voltage area ablation reduces, atrial fibrillation recurrence in persistent atrial fibrillation, a systematic review, meta analysis, and trial sequential analysis. This is a 2026 advanced publication in Clinical Electrophysiology.
Niraj Sharma:The unresolved question is whether a measured atrial substrate can guide useful treatment beyond pulmonary vein isolation. Low voltage isn't a histological diagnosis. Rhythm, wavefront direction, electrode configuration, and tissue contact influence what we label abnormal. The intervention therefore includes both the mapping strategy and the lesions delivered in response. Seven randomized trials reported fourteen eighty seven participants with twelve-eighteen months of follow-up.
Niraj Sharma:All used radiofrequency energy. Four trials randomized patients only after identifying low voltage substrate, an important distinction from treating an unselected persistent atrial fibrillation population. The primary pooled outcome was timed to first recurrent atrial fibrillation or atrial tachyarrhythmia after the index procedure. Mapping rhythm, voltage thresholds, substrate modification, surveillance and antiarrhythmic withdrawal varied. Some hazard ratios were reconstructed from survival curves and one trial contributed final conference results rather than a complete final publication.
Niraj Sharma:The pooled hazard ratio was 0.67, with a 95% confidence interval from 0.50 to 0.88 and a p value of 0.004. That estimates a 33% reduction in recurrence hazard, not a 33 percentage point absolute reduction. Without a common baseline risk and time horizon, a pooled number needed to treat would imply precision these data don't provide. That pooled estimate brings together seven trials: Erase AF, Stable SR2, Scar AF, Suppress AF, Solve AF, Ideal AF, and the trial by Huang et al. Each compared pulmonary vein isolation alone with isolation plus low voltage area ablation, but patient selection, voltage mapping, and substrate treatment differed, and the trials didn't show a uniform benefit.
Niraj Sharma:The initial I2 was 55%, indicating appreciable variation between trial results beyond chance. To explore that variation, the investigators repeated the meta analysis seven times, leaving out a different trial each time. This tests whether one study drives the pooled benefit or the inconsistency. IDEAL AF emerged as the main contributor. It remained part of the primary analysis, but removing it in this sensitivity analysis reduced I2 to 19%.
Niraj Sharma:The pooled hazard ratio moved from 0.67 to 0.74, with a 95% confidence interval from 0.59 to 0.92. The estimated benefit became smaller but remained statistically significant. Why might ideal AF have differed? It reported a larger treatment effect with a hazard ratio of 0.39. The authors noted that it was the only trial where operators were blinded to the voltage map during pulmonary vein isolation.
Niraj Sharma:That could limit inadvertent treatment of adjacent low voltage tissue in the isolation only group. Participants also had the longest median atrial fibrillation duration (thirty six months), and only thirty two percent were free of atrial fibrillation or atrial tachycardia after a single isolation procedure at twelve months. These are possible explanations for the variation, not established mechanisms. Ideal AF wasn't discarded as invalid. The benefit persisted without this influential trial.
Niraj Sharma:The trade off was additional treatment. Procedure duration increased by 30.5 and radiofrequency duration by twelve point three minutes. Repeat ablation wasn't significantly reduced. Risk ratio 0.70 with an interval from 0.49 to 1.01. Preventing a recorded recurrence and avoiding another procedure are different outcomes.
Niraj Sharma:Major complications occurred in three point two versus two point eight percent. The risk ratio of one point one two had an interval from 0.60 to 2.10. That doesn't establish equivalent safety. The interval permits more than a doubling of complications. Longer term atrial mechanical effects and organized tachycardia also remain insufficiently characterized.
Niraj Sharma:Trial sequential analysis crossed its benefit boundary at 68% of the specified information size under assumptions including a 30% hazard reduction. This strengthens the statistical signal but doesn't resolve differences in eligibility, monitoring, or lesion strategy. Reporting discrepancies also remain. The abstract gives fourteen eighty seven participants. Table one randomized counts total fifteen eighty seven.
Niraj Sharma:Table two analyzed groups total fourteen fifty six. The stated search date follows acceptance. We retain the authors' estimates while flagging these unresolved inconsistencies. The EP edge take, reproducible low voltage substrate, deserves consideration within an individualized radiofrequency strategy. These findings don't justify empiric atrial debulking or establish that the same lesion approach works with pulsed field energy.
Niraj Sharma:Future trials should standardize mapping and lesion endpoints, use continuous monitoring, and measure arrhythmia burden, quality of life, atrial function and repeat intervention. The decision remains whether the benefit from additional lesions justifies their additional exposure. Extra lesions are not without complications. That question becomes particularly concrete when the extra lesion lies near a coronary artery. Devi Nair et al.
Niraj Sharma:Report chronic impact of CTI ablation on the adjacent right coronary artery, pulsed field versus radiofrequency versus no ablation in the impact study. This is an October 2026 accepted pre proof in JAAC, Clinical Electrophysiology. Acute coronary spasm is already a recognized concern with pulsed field delivery near coronary vessels. The question here is different: what happens to vessel caliber over subsequent months, and does radiofrequency provide a safer comparison? This retrospective imaging registry screened two thirty three patients with baseline computed tomography.
Niraj Sharma:One hundred and fifty five had interpretable paired imaging, thirty nine after pulsed field isthmus ablation, fifty nine after radiofrequency, and fifty seven without isthmus ablation. Readers were blinded to treatment and time point. The primary endpoint was at least 10% reduction in right coronary caliber at the last available scan. Most imaging follow-up was around four months. Only thirty seven patients had a second scan around ten months, and those scans were preferentially obtained after initial narrowing.
Niraj Sharma:The study therefore doesn't provide uniform long term surveillance of the original cohort. Pulsed field treatment predominantly used a pentaspline catheter with six focal linear cases. Every pulsed field patient received intravenous nitroglycerin prophylaxis with blood pressure support. Radiofrequency used a lattice tip catheter. These are comparisons of particular treatment workflows, not isolated energy effects across interchangeable catheters.
Niraj Sharma:At least 10% narrowing occurred in five of thirty nine pulsed field patients, nine of fifty nine radiofrequency patients, and two of fifty seven controls. The respective rates were twelve point eight, fifteen point three, and three point five percent. The pulse field minus radiofrequency risk difference was -2.4 percentage points with a confidence interval from -15.8 to plus 13.1. A p value of one doesn't establish equivalence. The interval permits clinically important differences in either direction.
Niraj Sharma:At least 20% narrowing occurred in seven point seven, thirteen point six, three point five percent respectively. No patient developed at least 70% stenosis or a recognized ischemic event. All 16 narrowing events in impact CTI occurred in patients with baseline coronary disease. Within the ablation groups, fourteen of sixty four patients with coronary disease developed narrowing, compared with none of thirty four without it. But baseline coronary disease and prior ablation differed between groups, and 16 events couldn't support reliable multivariable or propensity adjustment.
Niraj Sharma:The absence of events in thirty four patients isn't evidence that absence of coronary disease guarantees protection. Secondary mixed model comparisons suggested differences between radiofrequency or pooled ablation and controls. Nonparametric patient level analyses didn't reproduce those findings. Imaging exclusions, calcium blooming, and the lack of formal reproducibility testing further limit interpretation of small caliber changes. Our earlier Issue 11 discussion supplies essential context: Tam et al.
Niraj Sharma:Effect of pulsed field ablation on human coronary arteries. A longitudinal study with intracoronary imaging appeared in JACC Clinical Electrophysiology in July 2025. Nineteen patients had paired optical coherence tomography of 20 vessels, including 18 right coronary arteries. At three months, median wall area increased 17.1% and median luminal area decreased 10.1%. An illustrated individual case showed approximately 64% corrected luminal area reduction.
Niraj Sharma:That observation shouldn't be described as typical 50% intimal thickening. Imaging identified structural remodeling. Human histology didn't establish intimal hyperplasia. Malyshev et al. Nitroglycerin to ameliorate coronary artery spasm.
Niraj Sharma:During focal pulse field ablation for atrial fibrillation appeared in the same journal in May 2024. Angiography detected moderate or severe spasm in four of five patients without nitrate pretreatment, despite no ST segment changes. With repeated central NTG, two of ten had mild or moderate spasm and none severe. This small, non randomized study addressed acute vasomotor behavior, not late structural injury. The EP EDGE take: Preventing severe acute spasm cannot be assumed to prevent chronic remodeling.
Niraj Sharma:TAM demonstrates that delayed change can occur. Impact CTI adds radiofrequency and untreated comparisons but doesn't establish the safer energy source. Baseline coronary disease deserves attention as a risk marker, without being promoted into a proven causal explanation. The practical response is to avoid unnecessary isthmus lesions, consider coronary proximity, and recognize the limits of clinical ischemia as a safety endpoint. These findings support prospective standardized imaging, not routine invasive surveillance for every asymptomatic patient.
Niraj Sharma:Stroke prevention brings us from measuring rhythm to weighing clinical outcomes. Laudani et al. Examined catheter based left atrial appendage closure versus oral anticoagulation in patients with atrial fibrillation. A systematic review and meta analysis in JAMA Cardiology, October 2026. Eight randomized trials enrolled 7,434 patients and contributed twenty two thousand four hundred and forty one patient years.
Niraj Sharma:Weighted follow-up was thirty seven point nine months. Populations included general atrial fibrillation cohorts, patients after ablation, and patients undergoing transcatheter aortic valve replacement. Comparators included warfarin and direct oral anticoagulants. This mustn't be presented as a uniform comparison against contemporary direct oral therapy. The primary outcomes were all stroke and major bleeding.
Niraj Sharma:Incidence rate ratios accounted for observation time. All stroke had a ratio of 1.08, with a confidence interval from 0.82 to 1.41. Major bleeding had a ratio of 0.96, with an interval from 0.81 to 1.14. Neither comparison established superiority or equivalence. Secondary analyses separated outcomes that can move in opposite directions.
Niraj Sharma:Ischemic stroke was more frequent with closure in the primary model. Ratio 1.34, interval 1.01 to 1.77. Non procedural major bleeding was less frequent. Ratio 0.73. Interval 0.58 to 0.92.
Niraj Sharma:All cause mortality had a ratio of 0.93. Interval 0.79 to 1.10. The sensitivity analysis is important. With Hartung NAP inference, the ischemic stroke estimate became 1.40, with an interval from 0.97 to 2.03. Non procedural bleeding remained 0.73, but its interval widened to 0.52 through 1.01.
Niraj Sharma:Both crossed unity. That doesn't make the directional findings disappear. It makes the certainty of a positive versus negative statistical classification less robust to the chosen method. With only eight trials and multiple secondary comparisons, a narrowly significant result shouldn't carry the entire treatment argument. The appendage closure analysis also forces us to consider timing.
Niraj Sharma:A time average rate ratio can obscure an early procedural hazard and a later reduction in bleeding. Lower non procedural bleeding isn't the same claim as lower total major bleeding, and the primary analysis didn't establish the latter. Pooled procedural rates per 1,000 patients included approximately five strokes, nine major bleeds, one death, five device embolizations, and nine effusions requiring intervention. These categories can overlap and shouldn't be summed as separate affected patients. Their clinical consequences also differ, which limits the usefulness of collapsing everything into one composite.
Niraj Sharma:Absolute benefit depends on baseline stroke and bleeding risk, duration of follow-up, and the competing risk of death. The pooled rate ratios don't yield a dependable universal number needed to treat. Devices, post implant drugs, and trial populations varied, and aggregate data cannot identify every subgroup likely to derive a net benefit. Most randomized participants could receive anticoagulation. The evidence therefore doesn't directly settle the problem of a patient with an absolute contraindication.
Niraj Sharma:Conversely, preference to avoid a long term medication doesn't make the procedure's early risks or subsequent antithrombotic requirements disappear. Piccini's accompanying editorial emphasizes that appendage exclusion doesn't remove every ischemic stroke mechanism. That is particularly relevant when the overall stroke result and the ischemic stroke signal are discussed together. A technically successful occlusion can coexist with residual non appendage thromboembolic risk This is a preference sensitive decision with outcomes that need to remain separate. Discuss procedural events, disabling stroke, subsequent bleeding, medication exposure, and imaging, follow-up explicitly.
Niraj Sharma:These findings don't support routine replacement of well tolerated anticoagulation. The next useful evidence should identify absolute net benefit using contemporary devices and standardized drug regimens while reporting stroke severity and patient reported outcomes. Successful closure is a procedural achievement. The clinical objective remains better long term stroke prevention with an acceptable burden of harm. The next four papers address practical electrophysiology decisions.
Niraj Sharma:Correa Velasquez et al. Studied conduction time criteria for confirming entrainment and macro reentry in atrial tachycardia, with 104 analyzable patients. Using four atrial sites at matched pacing rates, the first criterion compared conduction along the same pathway during overdrive pacing of tachycardia versus pacing in sinus rhythm. The second compared conduction from site A to site B with conduction from B to A during tachycardia without requiring sinus rhythm. Thresholds of sixty and sixty three milliseconds yielded sensitivities of 9596% respectively, with no false positives in study controls.
Niraj Sharma:The principle is that entrainment can force the paced wavefront to take a longer route around the circuit. The EP edge take, promising but thresholds derived in this cohort, partly simulated focal controls and dependence on electrode placement require external validation. Chakupi et al. Evaluated acute performance, safety, and feasibility of a mapping integrated balloon in basket pulsed field system. This single center cohort included one hundred and thirty three patients, ninety four with paroxysmal and thirty nine with persistent atrial fibrillation.
Niraj Sharma:Beyond pulmonary vein isolation, thirty four underwent posterior wall isolation. Twelve patients received other lesion sets anterior mitral lines, CTI ablation, roof lines, a posterior mitral line, and SVC isolation. Nitrates were given before mitral line and CTI ablation to reduce coronary spasm. Reported acute pulmonary vein isolation success was ninety six point two percent. Twelve of eighty two patients eligible for longer follow-up had late recurrence without mandated continuous monitoring.
Niraj Sharma:Two procedural complications and one acute kidney injury in the biomarker subset warrant attention. The EP edge take: feasibility doesn't establish benefit from additional lesions or settle coronary and renal safety. Alhidi's Danish registry study compared three approaches during first time pulsed field ablation in twelve sixty nine patients: deep sedation, administered by trained electrophysiology nurses under electrophysiologist supervision, deep sedation administered by an anesthesia nurse, and general anesthesia with endotracheal intubation. Both deep sedation approaches used propofol with opioids and spontaneous ventilation. One year recurrence was approximately twenty two-twenty three percent across groups, and anesthesia backup was rarely required.
Niraj Sharma:However, strategy and patient selection depended on the institution, and the safety definition could miss transient disturbances managed without escalation, the epedge take, Assess screening, staff training, monitoring, and immediate rescue capability. These data don't establish equivalent safety between staffing models. Singai Reddy et al. Asked whether flecainide or propafenone increased ventricular arrhythmias or mortality in patients with atrial fibrillation and structural heart disease including coronary disease, heart failure, or left ventricular hypertrophy. Seven studies included 35,886 patients.
Niraj Sharma:Six were pooled. Comparisons with other antiarrhythmics or no treatment were predominantly observational. The ventricular arrhythmia hazard ratio was zero point seven three, with a 95% confidence interval from zero point five one to one point zero three. Mortality was also not significantly different. The EP edge take, selective prescribing, heterogeneous disease, and prediction intervals allowing harm prevent calling these drugs safe across structural heart disease.
Niraj Sharma:Stable coronary disease, infarct scar, and ventricular dysfunction require separate judgments and prospective testing. Shamohamadi, Sanders, et al. Synthesized 17 cohorts examining blood pressure and atrial fibrillation. Mortality showed a U shaped association, while higher systolic pressure was strongly associated with intracranial hemorrhage. The modeled mortality nadir near 134 millimeters of mercury isn't a randomized treatment target, and low pressure may identify frailty or ventricular dysfunction.
Niraj Sharma:The EP edge take is to address hypertension while investigating the clinical meaning of low pressure rather than prescribing directly from an observational curve, Conjus HEAL LAA study enrolled 500 patients to evaluate a coded appendage occluder against performance goals. The six month safety composite was eleven point one percent, and no leak greater than five millimeters appeared among four zero four evaluable forty five day studies. Device thrombus still occurred, later imaging denominators fell. And non randomized medication selection complicates interpretation. The epedge take, consistent with MANCAD and Ellen Bogen's concerns, is that meeting a benchmark doesn't isolate a coding benefit or justify shorter antithrombotic treatment.
Niraj Sharma:Whittington's molecular thrombus imaging cohort included one hundred predominantly minor stroke patients with cardiovascular tracer uptake in sixty three. Classification changed in '26, but reclassification wasn't validated by a trial of imaging guided treatment. The recurrence hazard ratio of ten point four had a very wide interval, 1.35-79.4, and the paper has an unresolved discrepancy in uptake group counts. The EP edge take is biological proof of concept requiring validation before tracer positivity directs anticoagulation or intervention. Rita Rubin's JAMA Caffeine article is medical news, not a new trial.
Niraj Sharma:It distinguishes ordinary coffee and tea from high dose energy products and discusses preparation, individual tolerance, and largely observational associations. Approximately four hundred mg daily is described as a generally tolerated upper amount for many adults, not a preventive target or a uniform recommendation. The EP EDGE take is an individualized conversation about dose, sleep, symptoms, and preparation without automatically banning tolerated coffee or prescribing it for cardiovascular protection. As we wrap up issue 41, let's bring together the main implications for our practice. Virk's meta analysis supports considering targeted low voltage area ablation in selected patients with persistent atrial fibrillation, while differences in mapping, lesion strategy, and monitoring limit a universal prescription.
Niraj Sharma:Impact CTI reminds us that preventing acute coronary spasm and observing no clinical ischemia don't exclude delayed coronary changes after ablation near the right coronary artery. Zuo's Smartwatches study shows the potential for tracking atrial fibrillation burden, but accuracy must be interpreted alongside how much time the device actually provides usable recordings. Loudini's appendage closure analysis reinforces the need to weigh procedural complications, ischemic stroke, and subsequent bleeding separately when discussing closure versus anticoagulation. The other papers add practical considerations. Correa Velasquez's conduction time maneuvers offer additional ways to confirm macro reentry, with independent validation still needed before we generalize the derived thresholds.
Niraj Sharma:Chakopee's balloon in basket experience supports the feasibility of pulmonary vein isolation and selected additional lesions, including posterior wall and mitral line ablation, but doesn't establish that extending treatment beyond the veins improves outcomes. Alhade's Danish sedation study highlights the importance of patient selection, staff training, monitoring, and rescue capability when evaluating deep alongside general anesthesia. Singieredi's review raises questions about class Ic drug restrictions in selected structural heart disease populations, but observational associations don't establish safety in patients with infarct scar or ventricular dysfunction. Shah Mohamedy, Sanders, et al. Found: A U shaped association between blood pressure and mortality in atrial fibrillation, alongside greater intracranial hemorrhage risk at higher systolic pressures.
Niraj Sharma:The apparent mortality nadir isn't a randomized treatment target. Kanjia's coded appendage device study met its performance benchmarks but doesn't isolate a coding benefit or establish that antithrombotic therapy can safely be shortened. Whittington's molecular thrombus imaging study offers a promising way to identify possible embolic sources after stroke, although changes in diagnostic classifications still need to translate into better treatment outcomes. And Rita Rubin's caffeine discussion supports an individualized assessment of dose, preparation, sleep, and symptoms, while distinguishing ordinary coffee and tea from high dose energy products. Before we close, I'd like to thank everyone who has emailed or contacted us from across the wider epedge audience.
Niraj Sharma:I particularly appreciate colleagues bringing studies to my attention that I hadn't previously come across. Those exchanges broaden our reading and help shape future issues. Please keep the papers, questions, suggestions and emails coming. You'll find the full newsletter and references on LinkedIn and at epedge.substack.com. Questions, suggestions or concerns can be emailed to epedgeCast@gmail.com
Niraj Sharma:Thank you for listening and for sharing EP EDGE with your colleagues. This is Doctor. Sharma. Until next time, take care and bye for now.