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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:Hello and welcome back to EP Edge Journal Watch. I am Doctor. Sharma and this is Issue 23 May 2026. First thank you for listening, reading, sharing and sending suggestions. I really appreciate the feedback.
Niraj Sharma:Based on that feedback, we are going to try a slightly different format today. The full EP Edge Journal Watch newsletter still covers all 12 studies in detail with methodology, statistics, limitations, graphics, and references. But for the podcast, we are going to make the listening experience more focused. So today, we will do four main comprehensive analysis and then a rapid fire review of the remaining studies. The goal is to keep the episode conversational, practical, and useful without turning it into a marathon.
Niraj Sharma:The four featured studies today are: first, durability of pulmonary vein isolation, does the pulsed field ablation system matter? Second, adjunctive posterior wall ablation with a balloon in basket pulsed field ablation catheter from the Volt CE Mark study. Third, safety and midterm outcome of focal pulsed field ablation for outflow tract PVCs and fourth, our EP Edge Off Track Analysis midlife cardiorespiratory fitness and healthy aging. The theme this month is very clear, PFA is moving from acute success to durable success. We are no longer just asking can we isolate the veins, we are asking does the lesion last, does the platform matter and what should the endpoint be.
Niraj Sharma:Let's get started. Our first thorough analysis is: Durability of pulmonary vein isolation. Does the pulsed field ablation system matter? This is one of the most important PFA papers in this issue because it asks a question that is going to become increasingly relevant in everyday practice. When we say PFA are we talking about one technology or are we talking about multiple technologies that all use electroporation but may produce very different lesion sets?
Niraj Sharma:The early PFA story was about safety and acute pulmonary vein isolation and that was appropriate. We needed to know whether PFA could isolate veins efficiently with a lower risk of collateral thermal injury, but the next chapter is durability because for atrial fibrillation ablation acute PVI is not the finish line. The real question is whether those veins remain isolated months later. This study compared two PFA platforms, the Farapulse pentasplane catheter and the Volt balloon in basket catheter. That distinction matters.
Niraj Sharma:The pentaspline system depends on spline configuration, tissue apposition, and multiple overlapping applications. The balloon in basket system is designed to create more circumferential ostial contact with a different relationship between electrodes, tissue and the blood pool. So the study was not just asking whether PFA works, it was asking whether catheter architecture influences chronic PVI durability. Methodologically, this was a retrospective review from two Australian centers. The index cohort included eighty six patients treated with the pentaspline catheter and forty six patients treated with the balloon in basket catheter.
Niraj Sharma:Importantly, repeat mapping was performed only in patients who had clinical recurrence after the blanking period. So this was not mandatory remapping of everyone. That is a key limitation and it shapes how we interpret the results. At the repeat procedure, the investigators performed high density voltage mapping to assess pulmonary vein durability and posterior wall durability before any additional ablation was delivered. Now to the results.
Niraj Sharma:Over a median follow-up of about fourteen months, eighteen patients had clinical recurrence, nine in each group, seventeen of those patients underwent repeat electrophysiology study. The major finding was striking. Pulmonary vein level reconnection was two point nine percent with the balloon and basket system compared with twenty eight point one percent with the pentaspline system. The p value was 0.003. Let us translate that.
Niraj Sharma:A p value of 0.003 means that if there were truly no difference between platforms, observing a separation this large would be unlikely. It does not prove causality by itself but it tells us this is not a subtle signal. Patient level durability was also better with balloon in basket PFA 88.9% versus 37.5%, but here is the fascinating part. Clinical recurrence was not clearly lower with balloon and basket PFA. In the propensity matched cohort, recurrence rates were similar: twenty point six percent versus seventeen point six percent.
Niraj Sharma:That sounds paradoxical, but it is actually very instructive. Pulmonary vein durability and clinical recurrence are related, but they are not the same endpoint. Once you make the veins more durable, the remaining recurrences may come from non PV triggers, posterior wall substrate, atrial myopathy, or more intensive rhythm monitoring. There was also an interesting posterior wall signal. Posterior wall isolation was associated with lower arrhythmia recurrence in the combined cohort, four point three percent with posterior wall isolation versus seventeen point six percent without it.
Niraj Sharma:EP Edge take. This paper strongly suggests that PFA platform architecture may matter. It does not prove definitive platform superiority. Because the study was retrospective, the redo cohort was small, and mapping was clinically driven. But it pushes the field in the right direction.
Niraj Sharma:For practice the message is this: Acute PVI is no longer enough as a procedural quality metric. We need durable PVI, better endpoints and platform specific durability data. The future PFA conversation will not just be about energy source, it will be about lesion architecture. Before we move to posterior wall ablation, let us do the first rapid fire companion paper because it fits perfectly with the durability discussion. The study is residual tiny pulmonary vein, potentials on high resolution mapping, after pulsed field ablation predict atrial arrhythmia recurrence and poor durability of pulmonary vein isolation.
Niraj Sharma:This study asked a very practical question. After PFA, if the vein looks isolated by the ablation catheter but high resolution mapping still shows tiny residual signals. Should we care? The investigators studied one hundred and fifty eight patients undergoing initial AF ablation with a single shot PFA device. After ablation, they performed high resolution mapping.
Niraj Sharma:Residual tiny pulmonary vein potentials were defined as low amplitude electrograms with bipolar voltage of at least 0.03 millivolts. These residual tiny signals were found in thirty percent of patients. The presence of these signals was associated with AF or atrial tachycardia recurrence. The hazard ratio was two point six eight. That means patients with residual tiny potentials had about 2.7 times the time to event risk of recurrence compared with patients without those signals.
Niraj Sharma:The confidence interval was 1.14 to 6.31, so the estimate is imprecise but statistically significant. Among patients who underwent repeat ablation, eighty one percent of residual tiny potential sites were concordant with late reconnection sites. EP Edge rapid take. This may be the next PFA endpoint conversation, not just are the veins isolated but are there residual micro potentials that predict future reconnection. For practice I would not say we should chase every tiny signal tomorrow but I would say high resolution mapping after PFA may become more important as we refine endpoints.
Niraj Sharma:The full details are in the newsletter. Now to our second critical appraisal, adjunctive posterior wall ablation with a balloon in basket pulsed field ablation catheter in atrial fibrillation from the Volt CE Mark study. This study fits naturally after the durability paper. If PFA is making pulmonary vein isolation more durable, then the next question becomes what are we missing when patients recur despite durable veins? One candidate is the posterior wall.
Niraj Sharma:The posterior wall has always been an attractive target, particularly in persistent AF. But historically posterior wall ablation with radiofrequency has been controversial. It can be time consuming, it may not be durable, and the esophagus sits directly behind the left atrium which creates a real safety constraint for thermal ablation. PFA changes the conversation because it is non thermal and relatively myocardial selective. That does not automatically mean posterior wall ablation is beneficial but it may make it easier and safer to study properly.
Niraj Sharma:This VOLT study evaluated adjunctive posterior wall ablation using a balloon in basket PFA catheter. It was prospective, single arm, multicenter, and included fifty patients who underwent posterior wall ablation in addition to PVI. Twenty seven patients had paroxysmal AF and twenty three had persistent AF. Posterior wall ablation was performed at physician discretion. After ablation, mapping was used to confirm pulmonary vein and posterior wall endpoints.
Niraj Sharma:The catheter has integration with three-dimensional mapping and real time tissue contact assessment. That is important because posterior wall work is not just about energy delivery, it is also about controlled lesion placement and workflow. The results were strong from a feasibility standpoint. Pulmonary vein isolation was achieved 100% of veins, two hundred out of two hundred. Posterior wall ablation was confirmed in one hundred percent of treated patients, fifty out of fifty.
Niraj Sharma:Mean procedure time was about eighty minutes, mean fluoroscopy time was about fourteen minutes. The mean number of posterior wall applications was about 11. Operators rated the catheter easy or very easy to use on the posterior wall in eighty eight percent of cases. And importantly, there were no primary safety endpoint events through seven days. No deaths, no clinical strokes, no phrenic nerve injury, no clinical coronary artery spasm, and no clinically relevant hemolysis.
Niraj Sharma:Now here is the statistics and interpretation point. This was a single arm feasibility study. So when we hear one hundred percent acute posterior wall ablation that tells us the workflow can be done. It does not prove that posterior wall ablation improves long term rhythm outcomes. In other words feasibility is not the same thing as efficacy.
Niraj Sharma:EP Edge take, PFA may make posterior wall ablation technically easier, more efficient and potentially safer than thermal ablation, but the central question remains patient selection. Which patients should get posterior wall ablation? Persistent AF, enlarged left atrium, low posterior wall voltage, recurrent AF after durable PVI, documented posterior wall triggers, that is where the field needs to go. For practice today I would frame this as posterior wall PFA is technically ready for serious evaluation, but it should not become reflexive for every patient just because it is easier to do. The right future trial is not just PVI versus PVI plus posterior wall in everyone.
Niraj Sharma:It is phenotype driven posterior wall ablation with rhythm burden, durability and safety endpoints. Our third thorough analysis moves PFA beyond atrial fibrillation. The study is safety and midterm outcome of focal pulse field ablation for outflow tract premature ventricular contractions. This is a very interesting paper because it asks whether PFA can become a useful ventricular arrhythmia tool. Outflow tract PVC ablation is often straightforward when the site is in the right ventricular outflow tract, but it gets more difficult when the focus is in the left ventricular outflow tract, the left ventricular summit, the coronary venous system, or an intramural location.
Niraj Sharma:Radiofrequency can be limited by lesion depth, steam pop risk, access limitations, and proximity to the coronary arteries. So focal PFA is attractive because it may create non thermal lesions and may help in anatomically difficult regions, but ventricular PFA also raises important safety questions. Coronary vasospasm, conduction system injury, thromboembolism, and what happens when we deliver energy close to the LAD or septal This was a prospective multicenter study from four European centers. Eighty patients with symptomatic outflow tract PVCs underwent focal monopolar PFA using the Centauri generator. Follow-up at three and six months included clinical evaluation and twenty four hour Holter monitoring.
Niraj Sharma:Clinical success was defined as more than eighty percent reduction in daily PVC burden off antiarrhythmic drugs. Most PVCs came from the RVOT, about sixty one percent. The remainder came from the LVOT and left ventricular summit region. The efficacy results were impressive. Acute procedural success was achieved in all patients.
Niraj Sharma:At a median follow-up of eight months, clinical success was eighty eight percent. The median PVC burden decreased from twenty one point four percent before ablation to zero percent at follow-up. The p value was less than 0.001. By site, success was highest for RVOT PVCs at ninety four percent. Endocardial LVOT success was eighty nine percent.
Niraj Sharma:Left ventricular summit success was lower, around seventy two percent. The redo group is very important. Among patients with prior failed radiofrequency ablation, fourteen of fifteen had no recurrence. That is a strong practical signal. But the safety details are just as important.
Niraj Sharma:There was one ischemic stroke and seven minor complications. Coronary vasospasm occurred in two of twelve patients undergoing ablation from the great cardiac vein or anterior interventricular vein, both resolved with nitroglycerin. Right bundle branch block occurred during septal RVOT ablation in two patients, one transient and one permanent. Here is the statistics point. Two vasospasm events among twelve venous cases sounds like seventeen percent, but the denominator is small so the estimate is unstable.
Niraj Sharma:Still it is a meaningful safety signal because it occurred in exactly the anatomy we worry about. EP Edge take, focal PFA for outflow tract, PVCs looks promising especially for RVOT, endocardial LVOT, and redo cases after failed RF, but PFA does not erase anatomy. Coronary venous LV summit work remains a high attention zone. If you are near the great cardiac vein, anterior interventricular vein, or LAD, you still need coronary imaging, distance assessment, nitroglycerin readiness and a clear reason to proceed. For practice I would use this as a reason to watch focal ventricular PFA closely.
Niraj Sharma:It may become a valuable tool but the safest adoption will be anatomy driven and selective. Now let us move into rapid fire mode. These are shorter discussions but the full details are available in the Journal Watch newsletter. First rapid fire study: dronedarone versus amiodarone after AF ablation. This randomized open label trial compared twelve weeks of dronidarone versus amiodarone during the post ablation blanking period.
Niraj Sharma:The recurrence rate after blanking was twenty three point four percent with dronidarone versus sixteen point nine percent with amiodarone. The p value was 0.184, so the difference was not statistically significant, but side effects favored dronidarone forty point nine percent versus sixty four percent. QTc prolongation and hypothyroidism were both lower with dronedarone. The statistics pearl, non significant does not mean equivalent. This was not definitive proof that the drugs are the same.
Niraj Sharma:It suggests similar observed recurrence with a better short term safety profile for dronedarone in selected patients. Practice take: dronedarone may be reasonable after ablation when avoiding amiodarone toxicity matters, but amiodarone may still be preferred in more advanced substrate or high risk recurrence scenarios. Next, Artificial Intelligence versus Electrophysiologist Adjudication of Atrial Arrhythmias. This study compared AI rhythm adjudication with consensus review by three electrophysiologists. It included three sixteen insertable cardiac monitor episodes from three zero nine patients.
Niraj Sharma:The main statistic was Cohen's kappa, which measures agreement beyond chance. The mean pairwise kappa among electrophysiologists was 0.89. AI versus EP consensus was also 0.89. That means the AI agreed with the EP consensus about as well as EPs agreed with each other. Practice take: This is not about replacing electrophysiologists, it is about workflow.
Niraj Sharma:AI first triage with physician review for uncertain or high risk cases may become the future of rhythm monitoring and trial adjudication. Next rapid fire theme Brugada syndrome. The first Brugada study is prognostic value of small, cove type ST segment area in patients with spontaneous type one Brugada syndrome. This study evaluated a quantitative ECG marker, the maximum cove type ST segment area. Instead of only saying the ECG looks like type one Brugada, the investigators measured the area of the coved ST segment.
Niraj Sharma:In sixty spontaneous type one Brugada patients, twenty four experienced ventricular fibrillation during the clinical course. A smaller maximum coved ST segment area was associated with VF. The cutoff was less than 22, sensitivity was 50%, specificity was 86%, the AUC was 0.676. This is not a rule out test. Sensitivity of fifty percent means it misses too many events, but specificity of 86% means it may be useful as a risk enhancer when present.
Niraj Sharma:Practice take. This is not an ICD decision tool by itself, but it supports a future where Brugada risk stratification becomes more quantitative. The second Brugada paper is SmartBrugada, SmartWatch Margino Sternal Application for Recording, Type one Brugada Pattern. This proof of concept study tested Apple Watch recordings at high precordial margino sternal positions. It included 30 patients with known type one Brugada pattern and 60 healthy controls.
Niraj Sharma:Sensitivity was 7985% for the two operators. Specificity was 10098%. Inter observer agreement was excellent with kappa 0.94. The most useful single position was the third intercostal space at the left parasternal margin. Practice take.
Niraj Sharma:The smartwatch is not replacing the diagnostic ECG, but it may become a high specificity capture tool during fever, symptoms, drug exposure, or family screening. Next rapid fire study: Characterization of AV nodal, left inferior extension, by use of high density mapping and voltage time relationship. This is a niche paper, but it matters when the case is in front of you. Most typical AVNRT is successfully treated with right sided slow pathway modification, but rarely ablation needs to move to the coronary sinus roof or left atrial inferoceptal region. This study used high density mapping and ripple mapping to identify low amplitude, late activating, multicomponent electrograms in the inferoseptal left atrium, potentially consistent with a left inferior AV nodal extension.
Niraj Sharma:In one AVNRT case, right sided slow pathway and coronary sinus roof ablation failed. Left atrial septal mapping identified a late inferoseptal signal. Ablation there produced slow junctional beats, rendered tachycardia non inducible, and there was no recurrence through thirty one months. Practice take: This should not change routine AVNRT ablation, but when typical AVNRT does not behave typically, this paper gives a useful left sided mapping framework. Next, hemodynamic consequences and clinical outcomes with intravenous lidocaine infusion in patients with atrial fibrillation.
Niraj Sharma:This retrospective study included one hundred and ninety two AF patients who received IV lidocaine for ventricular arrhythmias. The population was high risk. Seventy nine percent had heart failure and mean ejection fraction was about thirty two percent. Lidocaine caused no significant change in heart rate. Systolic blood pressure and mean arterial pressure decreased modestly (about four-five mmHg).
Niraj Sharma:Only one patient had AF with rapid ventricular response attributed to lidocaine. Practice take: do not reflexively avoid lidocaine solely because the patient has AF. Monitor blood pressure, central nervous system effects, hepatic and renal context, and rate control, but the fear of lidocaine driven AF acceleration appears overstated. Now to our fourth and final deep dive and it is intentionally off track. The study is Midlife cardiorespiratory fitness and healthy aging.
Niraj Sharma:This is not an EP trial, it is not an AF ablation trial and importantly it is not an AF incidence but it belongs in EP Edge because the EP clinic is filled with the consequences of upstream substrate: hypertension, obesity, diabetes, sleep apnea, heart failure, chronic kidney disease, vascular disease, frailty, and multimorbidity. AF is often treated as an electrical disease, but in many patients it is the arrhythmic expression of aging, cardiometabolic disease, inflammation, adiposity, sleep disordered breathing, and declining physiologic reserve. This study used the Cooper Center longitudinal study linked to Medicare claims. It included twenty four thousand five hundred and seventy six participants, about twenty five percent women. Cardiorespiratory fitness or CRF was estimated using maximal treadmill testing before age 65.
Niraj Sharma:Participants were apparently healthy through age 65. Then the investigators used Medicare data to assess 11 major chronic conditions later in life. The outcomes were broader than one disease. They looked at health span, disease burden, disease years and lifespan. Health span means years lived without major chronic disease.
Niraj Sharma:Disease years capture both the number and duration of diseases. For example living with two diseases for one year counts as two disease years. That concept is clinically important because multimorbidity is often more meaningful than the first diagnosis alone. The results were clinically intuitive but still important. High fit men had one to 2% longer health span, which translated to about half a year to 1.3 additional healthy years.
Niraj Sharma:They also had two to 3% longer lifespan, corresponding to about 1.7 to 2.3 additional life years. High fit men had nine percent fewer major diseases after age 65. High fit women had about 2% longer health span, corresponding to roughly 1.3 additional healthy years. Some point estimates favored fewer diseases and longer lifespan, but not all were statistically significant. Across individual diseases, higher fitness was associated with disease onset at least one point five years later, and for some conditions three or more years later.
Niraj Sharma:Now the key clarification for an EP audience. This study did not test whether midlife fitness directly reduces atrial fibrillation. AF was not one of the measured outcomes, so we should not say this paper proves that fitness prevents AF. What we can say is that higher midlife fitness was associated with delayed onset of several upstream AF substrate drivers, including heart failure, diabetes, chronic kidney disease, ischemic heart disease and stroke or TIA, EP Edge, off track take. Fitness is not wellness fluff.
Niraj Sharma:It is substrate modification. For practice this supports a broader rhythm control conversation. Ablation, drugs and devices matter but long term rhythm health also depends on weight, blood pressure, sleep apnea, diabetes, activity, kidney function and fitness. For the patient in midlife the message is powerful. Cardiorespiratory fitness may delay the clustering of diseases that eventually drive arrhythmia, heart failure and frailty.
Niraj Sharma:In EP we often intervene downstream. This paper reminds us that some of the most important substrate modification happens years before the ablation procedure. So that is the new format for issue 23. Four deeper discussions and a rapid fire pass through the rest of the literature. The full newsletter goes into much more detail on all 12 studies including methodology, limitations, graphics, statistics and references.
Niraj Sharma:Now let us close with a quick recap. The PFA durability study suggests that catheter architecture may influence chronic pulmonary vein isolation even when clinical recurrence is more complex than vein reconnection alone. The residual tiny pulmonary vein potential study suggests that high resolution mapping may reveal small signals that predict recurrence and late reconnection. The Voalte posterior wall study shows that adjunctive posterior wall ablation with balloon and basket PFA is feasible and acutely safe, while long term efficacy and patient selection remain unresolved. The focal PFA study for outflow tract PVCs shows strong mid term efficacy, especially after failed RF, but coronary venous anatomy still demands caution.
Niraj Sharma:The dronedarone versus amiodarone trial supports individualized blanking period drug selection, with fewer side effects for dronedarone but no definitive proof of equivalence. The AI adjudication study for implantable loop recorders shows that AI can match EP consensus at a level similar to EP to EP agreement which could reshape monitoring workflows. The small ST segment area Brugada CoWave study adds a quantitative ECG risk marker, useful as a possible risk enhancer but not as a stand alone decision tool. Smart Brugada shows that Apple smartwatch recordings at high precordial marginal sternal positions may help capture intermittent type one Brugada pattern. The AV nodal left inferior extension mapping paper is niche but potentially valuable when typical AVNRT ablation does not behave typically.
Niraj Sharma:The lidocaine study suggests low AF proarrhythmic risk and only modest hemodynamic effects in AF patients treated for ventricular arrhythmias. Heparin STEMI reminds us that earlier therapy may improve pre PCI artery patency but hard outcome data are still needed and the midlife fitness study reminds us that health span and substrate modification begin long before the EP procedure. Before we close I want to share an important announcement. On June 1 we will release the first inaugural collaborative issue between EP Edge Journal Watch and the Heart Rhythm Society or HRS. This is a major milestone for EP Edge Journal Watch.
Niraj Sharma:It marks the beginning of a new monthly collaborative series with HRS, focused on bringing high impact electrophysiology literature to clinicians in a practical, thoughtful and clinically useful format. I want to sincerely thank all of you for helping make EP Edge Journal Watch successful. Your readership, listening, feedback, sharing and suggestions have helped build this platform into something meaningful for the EP community. This new collaboration with the Heart Rhythm Society is an important next step and I hope you will join me for this inaugural collaborative issue on June 1. Listeners will be able to access the episode through the Heart Rhythm Society website and HRS podcast feed, as well as through the regular EP Edge Journal Watch Feed, so it will be available through both platforms.
Niraj Sharma:All references and graphics for this issue are available on the LinkedIn newsletter, EP Edge Journal Watch, as well as on Substack at epedge.substack. Com. For questions, suggestions or concerns please email epedge. cast@gmail . com. Thank you again for listening.
Niraj Sharma:I appreciate your time, your feedback and your engagement. Take care, enjoy summer and bye for now.