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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
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:Welcome back to EP Edge Journal Watch. This is Doctor. Sharma and I'm glad you are here for issue 25 June 2026. First, thank you for the suggestions and questions. They help make this series more practical for the EP lab, clinic, consult room and journal club.
Niraj Sharma:I am also very excited about the EP Edge Journal Watch podcast with the Heart Rhythm Society. These papers deserve a deeper audio conversation because they change how we consent, monitor, prescribe and choose devices. The theme this month is beyond the binary. Stroke risk is not simply male versus female, ablation success is not recurrence versus no recurrence, PFA is not simply safe versus unsafe, ICD benefit is not only ejection fraction below 35% and device selection is not just lead versus no lead. We will cover stroke prevention, AF risk scoring, AF ablation endpoints, PFA workflow and biology, device strategy, battery longevity, competing defibrillator risk, and one EP lab pearl where the VA interval can absolutely fool you.
Niraj Sharma:We start with the option bleeding risk sub study with the editorial by Scavoni and DiBiase. The question was practical. After AF ablation, can left atrial appendage closure preserve stroke protection while reducing long term bleeding compared with oral anticoagulation. Option randomized sixteen hundred post ablation AF patients with elevated stroke risk, eight zero three to left atrial appendage closure with watchman flex, and seven ninety seven to anticoagulation. This sub study stratified patients by has blood score zero, one, two and three or higher.
Niraj Sharma:The primary effectiveness endpoint was death stroke or systemic embolism at 36 months That was similar between arms across as bled categories. The interaction p value was 0.73, meaning there was no evidence that the effectiveness of left atrial appendage closure differed by bleeding risk subgroup. The bleeding endpoint is the headline. In has bled zero, bleeding was seventeen point two percent with anticoagulation versus four point four percent with left atrial appendage closure. Hazard ratio 0.25.
Niraj Sharma:In has bled one, it was seventeen point two versus seven point five percent. Hazard ratio 0.41. A hazard ratio compares event rates over time. 0.41 means about a fifty nine percent lower relative hazard, but the absolute difference matters too. About ten fewer bleeding events per 100 patients over three years and has bled one.
Niraj Sharma:EP Edge, take low has bled, does not mean no bleeding risk. Option moves atrial appendage closure from only when anticoagulation is impossible toward a legitimate long term strategy discussion in selected post ablation patients. Next, female sex in AF stroke risk. McGarvey and colleagues asked whether female sex is a uniform independent risk factor or more of a risk modifier that matters mainly when age and comorbidity are present. Using TriNetX, they identified nine hundred forty two thousand six hundred forty two patients with non valvular AF from 2015 to 2025.
Niraj Sharma:They stratified patients by sex and age under 65, 65 to 74, and 75 or older. They then use CHADS WAH which removed sex from the score and performed one to one propensity matching. The outcome was cerebral infarction or arterial embolism over one year. In younger patients, female sex did not consistently increase risk. The signal appeared mainly in patients 75 or older.
Niraj Sharma:In older patients without additional risk factors and not anticoagulated, the hazard ratio was 1.244. That means about a 24% higher relative hazard, but the absolute rates were 0.783% versus 0.624 or roughly one extra stroke per six hundred twenty nine patients over one year. With one additional risk factor, the older female signal persisted, but the hazard ratio was only 1.065, and the absolute difference was about one extra stroke per nine fifty two patients per year. EP Edge take: Female sex should sharpen risk assessment in older comorbid patients, especially 75 and above. It should not automatically drive anticoagulation in otherwise low risk younger women.
Niraj Sharma:Now to early recurrence after PFA versus radiofrequency ablation. Villarreal and colleagues studied whether symptomatic early recurrence during the blanking period differs between PFA and RF and whether early recurrence still predicts late recurrence. This was a prospective registry from Beth Israel Deaconess. After propensity matching nine sixty two first time PVI patients were analyzed, four twenty RF and five forty two PFA. Early recurrence or ERAT was AF, flutter, or atrial tachycardia lasting more than thirty seconds within ninety days.
Niraj Sharma:Late recurrence was assessed after that through nine months. PFA had less early recurrence. Three month freedom from atrial arrhythmia was eighty six point six percent with PFA versus seventy three point eight percent with RF. The largest gap was in month one. Recurrence nine point eight percent with PFA versus nineteen point five percent with RF.
Niraj Sharma:After adjustment, PFA had a hazard ratio of 0.61 for early recurrence, meaning about a 39% lower relative hazard. But once early recurrence occurred, it strongly predicted late recurrence, hazard ratio 3.78 for first month early recurrence, and 4.1 for months two or three. EP Edge take PFA may reduce early inflammatory noise but early recurrence after PFA is not meaningless. It should prompt closer monitoring, phenotype definition, and rhythm optimization. The next paper may change how we talk about ablation success, burden based outcomes after AF ablation.
Niraj Sharma:Olmerad and colleagues studied one hundred sixty five patients with paroxysmal or persistent AF undergoing first time ablation after implantable loop recorder placement. Median follow-up was about forty one months. Antiarrhythmic drugs were stopped at three months and quality of life was tracked. The key metric was atrial tachyarrhythmia burden, the percent of monitored time spent in AF or atrial tachycardia. Across the cohort, median burden fell from fifteen percent before ablation to zero percent after ablation.
Niraj Sharma:In the seventy six patients who had recurrence, the result was even more provocative. Burden fell from ninety three percent to zero point four five percent. More than ninety percent of recurrent patients achieved at least a seventy five percent burden reduction. At four years, freedom from any two minute episode was fifty four percent, but freedom from a twenty four hour episode was seventy nine percent. Statistics translation, Kaplan Meier recurrence asks, when did the first episode happen?
Niraj Sharma:Burden asks, how much arrhythmia remains? A patient can fail a thirty second endpoint but have an enormous therapeutic response. EP Edge take, stop equating any recurrence with failure. Follow-up should include baseline burden, residual burden, symptoms phenotype and durability of benefit. Next, the time course of recurrence in paroxysmal AF ablation trials.
Niraj Sharma:Aguilar and colleagues asked whether the traditional twelve month follow-up endpoint is necessary for every paroxysmal AF ablation trial. They pulled 42 randomized trials with ten thousand two hundred forty six patients and reconstructed recurrence timing from published Kaplan Meier curves. Arrhythmia free survival was ninety point four percent at four months, eighty three point four percent at six months, seventy seven point two percent at nine months, and seventy two point eight percent at twelve months. The important finding recurrences were front loaded. Thirty five point nine percent of all twelve month recurrences had occurred by month four, sixty one point five percent by month six, eighty 5.2% by month nine.
Niraj Sharma:Six month survival predicted twelve month survival with a mean absolute error of 4.2%, meaning the prediction was off by about four percentage points on average. Statistics translation, this was reconstructed trial level data, not individual continuous monitoring. It is useful for trial design, not for saying an individual patient needs no long term follow-up. EP Edge take, trial follow-up may be shortened in selected paroxysmal AF studies but clinical monitoring should still match the purpose, symptoms, burden, stroke risk, heart failure or progression. Now left atrial size in persistent AF, does size matter?
Niraj Sharma:This CAPLA sub study asked whether left atrial volume index predicts ablation failure or whether it predicts recurrence burden and phenotype. CAPLA randomized persistent AF patients to PVI alone versus PVI plus posterior wall isolation. This sub study included two eighty one patients with baseline left atrial volume index and twelve month follow-up. Monitoring included implanted devices, loop recorders, twice daily mobile ECGs or Holters. Recurrence occurred in forty six point three percent at one year and sixty one point six percent at three years, but left atrial volume index did not independently predict binary recurrence.
Niraj Sharma:The odds ratio was one point zero one per milliliter per square meter with p equals zero point five five. But among patients who recurred, larger left atrial volume index was associated with more burden and persistent rather than paroxysmal recurrence. The odds ratio for persistent recurrence was one point seven eight per 10 milliliters per square meter. Statistics translation odds ratio 1.01 means left atrial volume index did not meaningfully change the odds of any recurrence, but 1.78 per 10 unit increase means larger atria strongly shifted the recurrence phenotype toward persistent AF. EP Edge take.
Niraj Sharma:A large left atrium should not automatically mean do not ablate, it should mean counsel differently. Expect higher burden and more persistent recurrence if recurrence happens. Now to PFA biology, thrombo inflammation and hemolysis after pentaspline PFA. Popa and colleagues studied sixty patients with paroxysmal AF undergoing first time PVI, thirty with pentaspline PFA and thirty with radiofrequency ablation. They measured inflammation, platelet activation, endothelial injury, hemolysis, nitric oxide and renal function at three time points.
Niraj Sharma:The rationale is important. PFA is tissue selective, but electroporation can still affect red blood cells. That can release free hemoglobin, deplete nitric oxide, and potentially interact with renal function, inflammation, and thrombosis. Intravascular hemolysis occurred in one hundred percent of PFA patients after an average of 40 two point eight deliveries. Nitric oxide decreased significantly in the PFA group only by about twenty six point five percent.
Niraj Sharma:No acute kidney injury occurred which is reassuring, but hemolysis burden correlated with creatinine increase, inflammation, platelet activation, and endothelial injury. Female sex was the only independent predictor of significant hemolysis. Odds ratio 7.8. Statistics translation, odds ratio 7.8 means nearly eightfold higher odds in this cohort, but the confidence interval was wide so the signal is important but imprecise. EP Edge take.
Niraj Sharma:PFA is not biologically silent. Use it efficiently. Optimize contact, avoid redundant applications and think carefully in patients with renal dysfunction, anemia or high anticipated lesion burden. The companion PFA paper is about workflow and durability. Rodriguez Munoz and colleagues asked whether pulmonary vein reconnection after pentasline PFA is mostly a waveform problem or a technique problem.
Niraj Sharma:This was a single center prospective study of first time pentasline PFA, PVI with planned invasive remapping at least thirty days after regardless of symptoms. One hundred and eighteen patients were enrolled, ninety four underwent remapping across three workflow phases. Phase one used systematic orthogonal fluoroscopy reference images, stability checks and repeat ablations if the catheter removed. Phase two added carina coverage and improved inferior vein mechanics. Phase three added left carina applications plus electro anatomical mapping and impedance guided assessment of spline distribution.
Niraj Sharma:Per vein durability improved from 89.8% to 92.9% to 99.2%. Per patient durability improved from 60% to 76.5% to 96.7%. Statistic translation per vein and per patient durability are very different. A few reconnected veins can translate into many patients with at least one reconnection. EP Edge take, PFA durability is workflow dependent but because more applications may increase hemolysis exposure, the answer is not simply more pulses, it's better pulses, better contact orientation, carina coverage and avoiding redundancy.
Niraj Sharma:Let's move to devices starting with subcutaneous ICD or S ICD in patients with prior monomorphic VT. The classic concern is lack of ATP. Monomorphic VT is often pace terminable, so choosing a subcutaneous ICD in someone with prior VT has been controversial. Boto and colleagues analyzed the rhythm detect registry across 37 Italian centers. Among two thousand one hundred and sixty four de novo S ICD implants, two ten patients had prior sustained monomorphic VT.
Niraj Sharma:Median follow-up was forty three months. Recurrence sustained monomorphic VT occurred in twenty one patients or ten percent with sixty six total episodes. All ventricular arrhythmias were successfully terminated by shocks. First shock efficacy was ninety three percent for both monomorphic VT and polymorphic VT or VF. Final success was one hundred percent.
Niraj Sharma:The annualized MVT rate was two point eight percent per year. Appropriate shocks were four point nine percent per year, inappropriate shocks two point eight percent per year, and complications two point three percent per year. About half of patients with recurrent MVT underwent ablation and no patient required conversion to a transvenous ICD for ATP. Statistics translation annualized rates average events over time, but risk is concentrated in a subset. Selection bias also matters because clinicians probably avoided S ICD in patients expected to need frequent ATP.
Niraj Sharma:EP Edge Take, prior monomorphic VT is not an automatic S ICD exclusion. The key is whether frequent stable ATP responsive VT is likely. Next is CRT DX versus conventional CRT D. The question is elegant, in CRT candidates without sinus node dysfunction, do we really need an atrial lead or do we simply need atrial sensing? CRT, next trial randomized six thirty six patients at 23 Italian sites to two lead CRT DX or conventional three lead CRT D.
Niraj Sharma:CRT DX senses the atrium using a floating atrial dipole on the right ventricular lead but does not pace the atrium. The primary endpoint was a one year composite of all cause mortality, cardiovascular hospitalization, and lead related complications. The endpoint occurred in thirteen point one percent with CRT DX versus fifteen point six percent with CRT D. The hazard ratio was zero point eight two, and non inferiority was met in both per protocol and intention to treat analyses. Atrial lead or atrial functionality complications were lower with CRT DX one point three percent versus four point two percent.
Niraj Sharma:Procedure time was shorter ninety two versus one hundred and seven minutes. Reverse remodeling was similar and only one CRT Dx patient later required a standard atrial lead. Statistics translation, non inferiority means CRT Dx was not unacceptably worse than CRTD within a pre specified margin. It does not automatically prove superiority. The clinical win is similar outcomes with less atrial lead burden.
Niraj Sharma:EP Edge take, do not implant an atrial lead by habit. Ask whether the patient needs atrial pacing or only reliable atrial sensing. Now the ICD battery longevity paper, this one matters for patients systems and cost. Freeman and colleagues use the Pacemate National Remote Monitoring data set analyzing ICDs implanted from 2003 to 2023. Over 15,000 single chamber ICDs, over 10,000 dual chamber ICDs, and over 17,000 biventricular ICDs.
Niraj Sharma:They compared time to replacement interval across BioTronic, Boston Scientific, Medtronic and Abbott. Replacement interval is the battery point where generator replacement planning begins. First every additional lead cost about two to three years of battery longevity. Second, manufacturer mattered. Among devices reaching replacement interval Boston Scientific Transvenous ICDs had the longest observed longevity across single chamber, dual chamber, and biventricular systems.
Niraj Sharma:Single chamber median longevity was one hundred fifty one point three months for Boston Scientific, one hundred twenty nine point five for Abbott, one hundred seven point four for Medtronic, and eighty four point zero for Biotronic. Dual chamber longevity was one hundred thirty four point one months for Boston Scientific, 108.6 for Abbott, 92.9 for Biotronic, and 91.7 for Medtronic. Biventricular longevity was one hundred ten point six months for Boston Scientific, 83.1 for Abbott, 78.2 for Medtronic, and 76 for Biotronic. Statistics translation, Kaplan Meier curves handled devices that had not yet reached replacement interval. Cox regression identified manufacturer, programmed pulse width, and programmed output as major drivers of longevity.
Niraj Sharma:EP Edge take battery longevity should enter device selection. Fewer unnecessary leads, careful programming and manufacturer differences may reduce lifetime generator changes, complications and potentially cost. Next, competing risk in primary prevention ICD patients with advanced heart failure. Barshashet and colleagues pooled 5,168 primary prevention ICD recipients from five trials, made it two, made it CRT, made it RIT, made it RIZK, and RAID. Patients were grouped by ejection fraction 20% or lower, twenty one to twenty nine percent, and thirty to thirty five percent.
Niraj Sharma:The primary endpoint was sustained VT or VF. The key statistical method was fine and gray, competing risk analysis because death from pump failure or nonarrhythmic causes can prevent observation of later VT or VF. At three years, sustained VT or VF occurred in twenty eight percent of patients with ejection fraction twenty percent or lower, twenty three percent with twenty one to twenty nine percent, and twenty percent with thirty to thirty five percent. Appropriate ICD shocks were seventeen, twelve, and eleven percent, but mortality also increased sixteen percent, ten percent, and nine percent across those same groups. Statistics translation, a subdistribution hazard ratio accounts for competing events.
Niraj Sharma:LV ejection fraction twenty percent or lower carried higher cumulative arrhythmic risk, but also substantially higher all cause mortality. The editorial frames it well, these patients have more shockable arrhythmia and more non shockable death. Both are true. EP Edge take, ICD consent should say both things clearly. You are at higher risk of a rhythm the ICD can treat and also at higher risk of dying from mechanisms it cannot treat.
Niraj Sharma:Our final paper is the EP lab pearl, the nearly zero VA interval trap. This vignette shows how slow slow atrioventricular nodal tachycardia or AVNRT with a prolonged lower common pathway can mimic typical slow fast AVNRT. The apparent VA interval may be less than seventy milliseconds or nearly zero. In the first case an 81 year old woman had tachycardia cycle length four hundred twenty four milliseconds, Ah interval three hundred fifty six milliseconds, and interval sixty eight milliseconds. That pattern could easily be called typical AVNRT, but ventricular overdrive pacing changed the diagnosis.
Niraj Sharma:The post pacing interval was five hundred seventy milliseconds and the tachycardia cycle length was four hundred eighteen milliseconds. So PPI minus TCL was one hundred fifty two milliseconds. A value greater than 115 argues against AVRT and supports AVNRT. After right inferior extension ablation, tachycardia persisted. Repeat PPI minus TCL was one hundred eighty two milliseconds.
Niraj Sharma:Left atrial mapping then found earliest retrograde activation at the left inferior extension and ablation there terminated tachycardia. EP methods translation in AVRT, the ventricle is part of the circuit, so PPI minus TCL is shorter. In AVNRT, the ventricle is outside the critical circuit, so it is longer. EP Edge take. If a near zero VA tachycardia behaves like AVNRT but will not die with right inferior extension lesions, map the retrograde limb.
Niraj Sharma:The VA interval can lie. Let's close with the rapid recap. This issue showed us that left atrial appendage closure after ablation may reduce cumulative bleeding exposure, female sex behaves more like a risk modifier than a universal stroke risk point, PFA reduces early recurrence but early recurrence still matters, AF burden may be more meaningful than first recurrence, and left atrial size predicts recurrence phenotype more than binary success. We also saw that PFA durability is workflow dependent. PFA hemolysis is real.
Niraj Sharma:S ICD may be reasonable in selected prior monomorphic VT patients. CRT DX can reduce atrial lead burden. ICD battery longevity differs by manufacturer and programming, very low ejection fraction creates both arrhythmic and competing mortality risk, and a near zero VA interval can fool you. All references and graphics are available on the LinkedIn newsletter, EP Edge Journal Watch, as well as on Substack at epedge. Substack . com.
Niraj Sharma:Questions, suggestions or concerns can be sent to epedge. Cast@gmail . com. Thank you again for listening to EP Edge Journal Watch. I appreciate your time, feedback and your commitment to thoughtful electrophysiology. Take care and I will see you in the next episode.