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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 EP Edge Journal Watch Issue 33 for August 2026. I'm Doctor. Sharma and it's great to have you with me. Before we begin, thank you for the thoughtful suggestions, concerns, questions. They're helping shape not only the podcast but the wider EP Edge project.
Niraj Sharma:Wherever you're listening from, the pace of events can feel relentless. New technology arrives quickly, information moves even faster, and certainty is often advertised before the evidence has earned it. That makes careful interpretation more important, not less. In electrophysiology, as in the wider world, judgement still matters. I am also pleased to announce the EP Edge app and the new EP Edge website at epedge.org.
Niraj Sharma:The app is being designed to bring the EP Edge ecosystem together in one place, including the podcast, journal watch, newsletters, EP Edge Rx, EP Edge Academy tools, and additional clinical and educational features. The website, epedge.org, will serve as the central digital home for all of this work. And please look out for the next EP Edge Journal Watch issue, which will again include collaboration with the Heart Rhythm Society. Now, this is a packed issue. We'll ask whether there's an optimal time to stop anticoagulation after successful atrial fibrillation ablation.
Niraj Sharma:We'll look at prophylactic pulmonary vein isolation for typical flutter and heart failure. We'll examine neurologic events and hemolysis with pulsed field ablation. Then we'll move into lead extraction, first asking whether prior sternotomy may reduce complications, and then exploring a new vibration based system. We'll also return to first principles in the EP laboratory with the line of block maneuver, and finish with two studies on sudden death risk, one using the ECG during atrial fibrillation and another examining a rare KCNJ8 variant linked with J wave syndromes. So let's begin with a question patients ask us all the time: After a successful atrial fibrillation ablation, when can the anticoagulant finally stop?
Niraj Sharma:The first paper is titled Optimal Timing for Oral Anticoagulant Discontinuation and Prognosis after Successful Catheter Ablation for Atrial Fibrillation. The lead author is Tomoya Iwawaki and it was published in July 2026 in JACC Clinical Electrophysiology. A patient feels better, the monitor looks reassuring, and the ablation appears successful. From the patient's perspective, the atrial fibrillation has been treated. So why continue a drug that carries bleeding risk?
Niraj Sharma:The difficulty is that ablation reduces rhythm burden, but it doesn't erase stroke biology. Silent atrial fibrillation may continue. Atrial fibrosis, vascular disease, age, and prior stroke remain. Yet keeping everyone anticoagulated indefinitely also creates avoidable bleeding. The investigators reviewed two thousand four hundred and forty eight first time ablation patients and repeatedly compared those who stopped anticoagulation with those who continued it at five thirty seven weekly time points.
Niraj Sharma:They used inverse probability weighting to make the groups more comparable, then created a reverse net clinical benefit model weighing bleeding against thromboembolism. The headline was eight point one months. That was the point where the modeled balance most favored discontinuation. But stopping at that time was still associated with more than twice the hazard of thromboembolism, with a hazard ratio of 2.364. Bleeding hazard was much lower, with a hazard ratio of 0.176.
Niraj Sharma:Mortality was not different. A hazard ratio compares event rates over time. It doesn't mean every patient who stops has twice the absolute stroke risk. It means events accumulated faster after discontinuation within this weighted observational model, while major bleeding accumulated much more slowly. The EP Edge Take is that eight point one months is not a biologic cutoff or an appointment date, it's the peak of a statistical model.
Niraj Sharma:The study was retrospective, treatment wasn't randomized, rhythm monitoring was intermittent, and practice changed across seventeen years. In practice, a low risk patient with durable rhythm control and meaningful bleeding concerns may reasonably be reassessed later than three months. A patient with prior stroke, substantial atrial disease, impaired ventricular function, or higher thromboembolic risk should not interpret this paper as permission to stop. For the complete curves, subgroup findings, and limitations, see the full EP Edge Journal Watch newsletter. Our second paper is Prophylactic Pulmonary Vein Isolation in Patients with Typical Atrial Flutter and Heart Failure.
Niraj Sharma:The lead author is Chu Heng Bian and it was published in August 2026 in Heart Rhythm. Typical flutter often looks like a procedural success story. We identify the circuit, create bidirectional CTI block, and the flutter is treated, but many patients later develop atrial fibrillation even when it was never documented before the flutter ablation. In a patient with heart failure, that new atrial fibrillation may lead to congestion, hospitalization or loss of clinical stability. So the investigators asked a provocative question: Should we treat only the flutter that's present or also isolate the pulmonary veins to prevent the arrhythmia that may come next?
Niraj Sharma:This was a prospective, multicenter, non randomized study from nine Chinese centers. Eighty one patients were enrolled, forty two received isthmus ablation plus circumferential pulmonary vein isolation and thirty nine received isthmus ablation alone. The primary outcome was death or hospitalization for worsening heart failure over about forty months. The primary endpoint occurred in thirty one percent of the combined ablation group compared with fifty six point one percent of the isthmus only group. The adjusted hazard ratio was 0.37, suggesting a sixty three percent lower event rate over follow-up.
Niraj Sharma:The difference was driven mainly by fewer heart failure hospitalizations. Atrial fibrillation also developed much less often, nine point five percent versus thirty eight point five percent. That sounds dramatic but treatment was determined by center, not randomization. Four centers performed the combined strategy, while five performed isthmus ablation alone. Treatment was therefore tied to the center's operators' heart failure management, follow-up culture, and hospitalization thresholds.
Niraj Sharma:There was also a procedural price. Adding pulmonary vein isolation more than doubled procedure time from about sixty six to one hundred and forty one minutes and required transseptal access in patients without documented atrial fibrillation. The EP Edge take is that this is not a reason to add pulmonary vein isolation to every typical flutter ablation. It is a strong reason for a randomized trial in patients with typical flutter and clinically significant heart failure. Sometimes flutter may be the first visible expression of a larger atrial disease process.
Niraj Sharma:The key question is whether preventing future atrial fibrillation improves enough meaningful outcomes to justify the additional procedure. Now let's turn to Pulsed Field Ablation and a paper titled Impact of Lesion Delivery and Irrigation Rates on Neurovascular Events with PFA for atrial fibrillation. The lead author is Musa Mansour and it was published in July 2026 in JACC, Clinical Electrophysiology. After the variable loop circular PFA catheter entered commercial use in The United States, four strokes or transient ischemic attacks were reported among the first 132 procedures. That was an observed rate of three percent, high enough to trigger a voluntary commercial pause.
Niraj Sharma:The deeper question was whether the problem came from the device, irrigation, application number, lesion stacking, ablation beyond the veins, catheter exchanges, anticoagulation, operator learning, or several factors together. The investigators reviewed 6,811 commercial procedures using the manufacturer's complaint database. They compared the early pre pause workflow with two post pause workflows, one using four mLmin irrigation and one using 30 during energy delivery. After the pause, the observed neurologic event rate fell from three percent to zero point two eight percent. At the same time, the average number of complete ablations fell from about 33 to 21, with less stacking and far less extrapulmonary vein ablation.
Niraj Sharma:Higher irrigation produced a numerically lower event rate: zero point two two percent versus zero point 39%. But the difference was not statistically reliable, so irrigation alone cannot be credited with solving the problem. The initial signal came from only four events, two at one center, in a very small denominator. After the pause, the denominator became more than 50 times larger, while several workflow variables changed simultaneously. The improvement is reassuring, but there's no single smoking gun.
Niraj Sharma:The EP Edge Take is practical. With the new PFA platform, device specific workflow matters. Avoid unnecessary applications and stacking. Reposition deliberately. Maintain careful sheath management and anticoagulation.
Niraj Sharma:Use the recommended irrigation protocol. And don't assume experience with one PFA system automatically transfers to another. This is also how post market surveillance should work. A signal appeared, use stopped, the workflow was examined, and practice resumed with tighter controls. What remains missing is an independent registry capturing lesion count, stacking, irrigation exchanges, activated clotting time, silenced cerebral lesions, and clinical events.
Niraj Sharma:Staying with PFA, the next paper is Hemolysis and Renal Safety of Pulsed Field versus Thermal Ablation for Atrial Fibrillation A Systematic Review and Meta Analysis. The lead author is Mustafa Ere Kilich and it was published in August 2026 in Heart Rhythm. The rationale is fascinating. PFA is often described as tissue selective, but the energy is delivered inside a blood filled chamber, red blood cells are exposed to high voltage fields, Electroporation can produce intravascular hemolysis. Most patients may show only a laboratory signal, but free hemoglobin can injure the kidneys and rare severe cases have been reported.
Niraj Sharma:The question was whether PFA causes more hemolysis than thermal ablation and whether that becomes acute kidney injury. The authors pooled 12 comparative observational studies involving five thousand one hundred and fifty eight patients. They examined hemolysis markers, creatinine, estimated filtration rate, acute kidney injury dialysis, and procedural complications. The answer was clear on hemolysis. PFA produced higher lactate dehydrogenase, lower haptoglobin, and higher bilirubin.
Niraj Sharma:The signal was strongest with some pentaspline platforms. The renal answer was less certain. Acute kidney injury occurred in three point five percent after PFA and three point one percent after thermal ablation. The pooled risk ratio was one point one four, with a confidence interval from 0.42 to 3.12. That interval means the analysis did not show a reliable difference but it also did not prove equivalence.
Niraj Sharma:The data remained compatible with lower risk, no difference, or a meaningful increase. Three PFA patients required dialysis, compared with none after thermal ablation, although the numbers were too small for a firm comparison. The EP Edge take is that PFA related hemolysis is real, while clinically significant renal injury appears uncommon at the population level. That should lead to dose discipline, not alarm. Assess baseline renal function, avoid unnecessary applications, hydrate appropriately, and consider post procedure creatinine and urine assessment in patients with chronic kidney disease, extensive lesion sets, high application counts, hemoglobinuria, or dark urine.
Niraj Sharma:PFA safety isn't only about the esophagus, phrenic nerve, or pulmonary veins. The blood and kidneys are part of the procedure too. Let's move into lead extraction. The next paper is Procedural Characteristics and Outcomes of Transvenous Lead Extraction in Patients with Prior Sternotomy. The lead author is Mohamed Medailli and it was published in July 2026 in JACC Clinical Electrophysiology.
Niraj Sharma:The study addresses a procedural paradox. Prior sternotomy may create scar that contains bleeding and reduces tamponade, But if a major tear occurs, that same scar can make repeat sternotomy slower and more difficult. The investigators used the Cleveland Clinic Extract Registry and included four thousand eight hundred and forty six patients treated between 1996 and 2022. Of these, thirteen forty four had a prior sternotomy. They compared outcomes using multivariable adjustment, then repeated the analysis in twelve fifty six matched pairs.
Niraj Sharma:Despite being older and carrying more comorbidity, prior sternotomy patients had fewer major complications, one point four percent versus three percent. Major cardiovascular injury occurred in one point two percent versus two point two percent, and rescue surgery was needed in zero point seven percent versus one point six percent. After adjustment, prior sternotomy was associated with an odds ratio of zero point five two for major complications, meaning roughly half the odds compared with patients without prior sternotomy. Tamponade was also less common, supporting the idea that adhesions may contain bleeding. But the second half of the story is crucial.
Niraj Sharma:Among the small number needing emergency rescue surgery, mortality was numerically higher after prior sternotomy: thirty three percent versus thirteen percent. The numbers were too small for a reliable conclusion, but the deaths involved difficulty locating and controlling bleeding during emergency reentry. The EP Edge take is that prior sternotomy may reduce the probability of a catastrophic extraction complication while increasing the complexity of rescue if catastrophe occurs. This should recalibrate planning, not relax it review the operative history consider detailed imaging choose the room carefully ensure immediate surgical availability, bridge balloon readiness, blood products and a defined rescue pathway. The major limitation is generalizability.
Niraj Sharma:These were outcomes from a very high volume center across twenty six years of evolving technology. Prior sternotomy is not permission to perform extraction without mature rescue infrastructure. The next lead extraction paper may be the most technically disruptive study in this issue. Its exact title is Novel Approach to Lead Extraction Utilizing Vibration Energy from Bench Experiments to a First in Human Study. The lead author is Orr Tomer and it was published in July 2026 in JACC Clinical Electrophysiology.
Niraj Sharma:Conventional extraction advances a mechanical or laser sheath over the lead and disrupts fibrotic attachments. It works, but it creates force where the lead meets the vessel, heart, valve, and surrounding tissue. This team asked whether controlled vibration could travel down a locking stylet, generate shear forces, and allow the lead to slip out of its fibrotic envelope without a cutting sheath. Development occurred in three stages: bench testing, animal studies and first in human use. Bench work identified a useful vibration range around 20 five-thirty five Hz.
Niraj Sharma:Animal studies included leads implanted for up to about five years. Then 10 patients underwent extraction of eighteen leads. Mean dwell time was about forty nine months. All 18 leads were completely removed. No mechanical extraction sheath was required.
Niraj Sharma:Mean vibration time was roughly thirty seven seconds per lead and no major procedural complication occurred. That is exciting but this is feasibility evidence not comparative safety evidence. 13 patients originally consented, one lead came out with traction alone and two cases were excluded because of technical malfunctions involving the anchoring system or controller. Those failures matter when judging a new device. The human leads were also not especially old.
Niraj Sharma:We still don't know how the system performs with heavy very old leads, damaged lumens, lumenless leads, occluded veins, retained neighboring leads, or systemic infection where residual fibrous ghosts may matter. The EP Edge Take is that this is a genuinely new mechanism and potentially an important additional tool. Moving the lead within its fibrotic casing may reduce some forms of mechanical trauma, but it should not reduce surgical backup, and it should not yet be viewed as a tool for lower volume programs. The next study must count every attempted case, including setup failure, inability to engage the lead, crossover, and incomplete extraction. This may become a new first tool.
Niraj Sharma:It is far too early for it to become the only tool. Now, back to the EP laboratory. The next paper is Line of block: A simple pacing maneuver to distinguish AV nodal from accessory pathway, ventriculoatrial conduction. The lead author is Ahmed Mokhtar and it was published in August 2026 in Heart Rhythm. Concentric retrograde atrial activation may represent AV nodal conduction or a septal accessory pathway.
Niraj Sharma:We have parahesian pacing, differential ventricular pacing, entrainment, and His refractory ventricular premature beats. Each is useful and each has pitfalls. The line of block concept starts with anatomy. The tricuspid annulus is normally an electrical barrier between ventricle and atrium. Without an accessory pathway, a basal right ventricular stimulus must travel toward the His Purkinje system before reaching the atrium through the AV node.
Niraj Sharma:Move the catheter toward the apex, and access to the conduction system should improve. If a septal pathway is present, the basal position is closer to it. Moving away from the annulus should lengthen the stimulus to atrial interval. The operator paces at the basal right ventricle and measures SA1, then moves the same catheter about two-four centimeters toward the apex and measures SA2. If SA1 is greater than SA2, that supports nodal conduction.
Niraj Sharma:If SA1 is less than SA2, that supports an accessory pathway. 24 patients were studied. Every pathway patient had a negative SA1 SA2, and every patient without a demonstrated pathway had a positive value. The group difference was highly significant. There is an internal inconsistency in the paper.
Niraj Sharma:The abstract and text describe 10 pathway patients and 14 without, while one table lists eleven and thirteen. That needs clarification. The EP Edge take is that this is an excellent proof of concept and a memorable corroborating maneuver. It is not yet a stand alone verdict. The sample is small, the catheter positions require standardization, and the maneuver has not been independently validated across difficult pathway types.
Niraj Sharma:Use it as another piece of physiologic evidence, especially when the traditional apex pacing position is uncertain. Don't let it overrule conflicting data from entrainment, parahesian pacing, activation mapping, or His Refractory ventricular stimulation. Our next paper asks whether an ECG recorded during atrial fibrillation can reveal hidden sudden death risk. The exact title is A Novel Electrocardiographic Risk Score for Sudden Cardiac Arrest in Patients with Atrial Fibrillation The lead author is Thiantan TriTitruyan and it was published in August 2026 in Heart Rhythm. Patients with atrial fibrillation are often excluded from ECG risk studies because the rhythm is irregular, QT correction is difficult, and repolarization measurements are less stable.
Niraj Sharma:This study asked whether that complexity still contains useful information. The discovery cohort included four forty seven sudden cardiac arrest cases and one hundred and thirty eight controls with atrial fibrillation or flutter on a prior ECG. The score was tested in a separate validation cohort with three fifteen cases and one hundred and thirty eight controls. Five ECG findings each received one point: prolonged corrected QT, a frontal QRST angle greater than 100 degrees, T peak to T end greater than ninety four milliseconds, ECG left ventricular hypertrophy and delayed precordial QRS transition. In discovery, each point was associated with a 1.5 fold increase in the odds of sudden cardiac arrest.
Niraj Sharma:A score of four or more had an odds ratio of twelve point nine. In validation, each point had an odds ratio of two point four and a score of three or more had an odds ratio of twenty two point nine. Those are large associations, but this was a case control study. The investigators deliberately assembled arrest cases and controls. A high score therefore doesn't provide a patient's absolute annual risk, and it cannot be read as a 23 fold increase in real world probability for every clinic patient.
Niraj Sharma:Discrimination was more modest. The area under the curve was 0.64 in discovery and 0.71 in validation. That is better than left ventricular ejection fraction alone, but not enough for a high stakes decision by itself. The EP Edge take is that the atrial fibrillation ECG should not be dismissed as noise. The score may enrich a research population or identify patients for deeper phenotyping.
Niraj Sharma:It is not an ICD score. Before clinical use, we need prospective cohorts, absolute event rates, automated measurements, medication adjustment, and comparison with imaging, scar, biomarkers, ventricular ectopy, and competing nonarrhythmic death. Our final study is Biophysical Characterization of a Novel Rare Variant Linked with Inherited and Acquired J Wave Syndrome. The lead author is Dan Hu and it was published in July 2026 in Clinical Electrophysiology. The study tries to connect Brugada syndrome, early repolarization syndrome, idiopathic ventricular fibrillation, and ventricular fibrillation during acute myocardial infarction.
Niraj Sharma:The proposed bridge is the ATP sensitive potassium channel. Under normal conditions, intracellular ATP helps keep it closed. During ischemia, ATP falls, the channel opens, potassium leaves the cell, and the action potential shortens. That may be adaptive, but excessive activity could create dangerous repolarization heterogeneity. The investigators screened four thirteen patients with Brugada syndrome or early repolarization syndrome, plus twenty five who developed ventricular fibrillation during acute myocardial infarction.
Niraj Sharma:They identified the A88G variant in three unrelated patients. They expressed the mutant channel in HeK293 cells and studied it with patch clamp techniques. The mutant produced about twice the whole cell current. Single channel conductance increased from about 46 to 73 picosemins, the channel stayed open about 27.5 ms versus 3.5, and the ATP concentration needed to inhibit half the channel activity rose from roughly 44 to more than 1,700 micromoles per liter. In practical terms, the mutant channel was more conductive, stayed open longer, and was far less responsive to ATP's normal breaking effect.
Niraj Sharma:The functional signal is powerful. The clinical genetic evidence is much weaker. There were only three carriers, no family co segregation analysis, no penetrance estimate, and one patient carried another rare variant. Experimental cells also cannot reproduce the full human myocardial environment. The EP Edge take is that A88G is a compelling functional variant, but it is not yet a clinically validated result that should determine family screening, prognosis, or treatment on its own.
Niraj Sharma:The most interesting possibility is a gene environment interaction. One carrier developed ventricular fibrillation during acute ischemia, exactly when ATP sensitive potassium channels become more active. That is a biologically attractive model. Proven? Not yet.
Niraj Sharma:Let's close with a rapid recap. The Iwawaki anticoagulation study suggests timing matters after atrial fibrillation ablation, but 8.1 is a modeled balance point, not a universal stopping date. The B and Flutter study raises the possibility that prophylactic pulmonary vein isolation may reduce future atrial fibrillation and heart failure hospitalization in selected patients, but randomization is still needed. The Mansor PFA analysis shows that a major early neurologic safety signal fell after workflow changes while leaving the exact causal factor uncertain. The Killick meta analysis confirms that PFA causes more biochemical hemolysis than thermal ablation, although population level acute kidney injury was not clearly increased.
Niraj Sharma:The MDALE extraction study suggests prior sternotomy may reduce major complications, while making emergency surgical rescue more difficult when complications occur. The Tomer first in human study shows that vibration based lead extraction is feasible and highly innovative, but still very early. The Moctar line of block study offers a simple way to distinguish nodal from septal accessory pathway conduction pending larger The Truyen SCAAFERS score shows that the ECG during atrial fibrillation may contain useful sudden death information, but it is not ready to guide ICD decisions, and the HuK CNG8 study provides strong functional evidence for a gain of function variant, while the clinical genetic evidence remains preliminary. All references and graphics are available in the LinkedIn newsletter, EP Edge Journal Watch, and on Substack at epedge. Substack . com.
Niraj Sharma:Questions, suggestions or concerns can be emailed to epedge. Castgmail . com. Thank you again for listening and thank you for continuing to support EP Edge. I'll see you in the next episode. Bye for now, and take care.