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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 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. I'm Doctor. Thank you as always for listening, for reading and for the thoughtful suggestions many of you have sent in. This episode is a special HRS 2026 edition focused on one trial that is already generating a lot of conversation: AVANT GUARD. The trial asks a very important question: In treatment naive patients with symptomatic persistent atrial fibrillation, should we move earlier toward pulsed field ablation as initial rhythm control therapy rather than starting with antiarrhythmic drugs?
Niraj Sharma:The headline answer is yes, at least for the selected population studied. Pulsed field ablation roughly doubled the chance of freedom from atrial arrhythmia at twelve months compared with antiarrhythmic drug therapy. The reported number was fifty six percent with PFA versus thirty percent with antiarrhythmic drugs, with a hazard ratio of zero point four six, but this is exactly the kind of trial where the headline is not enough. For this episode, the trial's manuscript and the supplemental material were evaluated in-depth. That matters because several of the most clinically important details are not captured by the abstract alone.
Niraj Sharma:The trial was paused during enrollment after neurological events. The protocol was tightened. The final enrolled population became narrower than the population that originally entered the trial. The antiarrhythmic drug comparator excluded amiodarone by design. And the positive efficacy result depends heavily on continuous monitoring and on a non traditional asymptomatic recurrence threshold.
Niraj Sharma:None of that invalidates the result, but it does change how we should explain the result to patients, fellows, APPs, and referring cardiologists. So today, we will walk through why the trial was done, how it was designed, what the primary efficacy and safety results mean, what happened with the study, pause, how to interpret the statistics, and finally the EP Edge take: how this trial should and should not change practice. Let's start with the rationale. Persistent atrial fibrillation remains one of the hardest rhythm control populations we manage. Drug therapy can work, but it often requires cardioversion, dose adjustment, hospitalization for initiation, and eventual escalation to ablation.
Niraj Sharma:Catheter ablation can reduce arrhythmia burden, but historically the question has been whether it should be used early in persistent AF, particularly before a patient has failed an antiarrhythmic drug. Pulsed field ablation changes that discussion because it offers a nonthermal ablation modality with a potentially favorable tissue selectivity profile. The clinical question is no longer simply, Can ablation work after drugs fail? The more contemporary question is, Should ablation be considered as the initial rhythm control strategy in selected patients? AVANT GUARD enrolled patients with treatment naive, symptomatic persistent atrial fibrillation.
Niraj Sharma:The AF duration had to be continuous for seven to three sixty five days. Patients were randomized two to one to pulsed field ablation using the Ferrapulse pentaspline catheter or to a class I or class III antiarrhythmic drug strategy. Importantly, amiodarone was excluded as a first line comparator. The randomized part included three ten patients, two zero seven assigned to PFA and 103 assigned to antiarrhythmic drug therapy. Every patient received a LuxDx implantable cardiac monitor, which is crucial.
Niraj Sharma:This was not a trial relying only on symptoms, office ECGs or intermittent halters. Continuous monitoring shaped the endpoint. There was also a second part to the study. After the randomized sample size was met, the protocol enrolled an additional 100 patients assigned to PFA for safety analysis only. These patients were not part of the randomized efficacy comparison, they were added to increase the total PFA treated cohort for the primary safety endpoint.
Niraj Sharma:This is one of the key structural points in the trial. AVANT GUARD is really two studies inside one protocol. Part A is a randomized superiority trial testing PFAS versus antiarrhythmic drugs for efficacy. Part B is a single arm PFA safety cohort compared against a pre specified performance goal. That means when we say the serious device or procedure related adverse event rate was five point one percent, we are not describing a direct randomized comparison against drug therapy.
Niraj Sharma:We are describing a single arm PFA safety result tested against a twelve percent benchmark. That distinction matters when we counsel patients. Now let's go to the primary results. The primary efficacy endpoint favored PFA. At twelve months, freedom from the composite efficacy failure endpoint was fifty six percent with pulsed field ablation and thirty percent with antiarrhythmic drug therapy.
Niraj Sharma:The hazard ratio was 0.46, with a 95% confidence interval from 0.33 to 0.65 and a p value less than 0.001. In practical terms, a hazard ratio of 0.46 means the PFA arm had about a 54% lower hazard of reaching the composite failure endpoint over follow-up compared with the drug arm. The confidence interval is fairly tight and does not cross one, so statistically this is a robust efficacy result. The p value tells us that the probability of seeing a result this extreme by chance, if there were truly no difference, is very low, but the key phrase is composite failure endpoint. The composite included several ways to fail: amiodarone use, electrical cardioversion, repeat ablation, detected arrhythmia recurrence, and for the PFA arm only, use of class I or class III antiarrhythmic drugs.
Niraj Sharma:For arrhythmia recurrence, symptomatic episodes of thirty seconds or longer counted. Asymptomatic episodes counted only if they lasted at least one hour. The primary safety endpoint was also met. In two fifty seven PFA treated patients, the device or procedure related serious composite adverse event rate was five point one percent at twelve months. The upper boundary of the ninety seven point five percent confidence interval was eight point six percent, which beat the pre specified twelve percent performance goal.
Niraj Sharma:That is a positive safety result by the trial's design. But again, it is not a head to head safety comparison against antiarrhythmic drugs. It is a comparison against a fixed historical benchmark. Arrhythmia burden also favored PFA. Median post blanking atrial arrhythmia burden was zero point zero percent with PFA compared with zero point three percent with antiarrhythmic drugs.
Niraj Sharma:Mean burden was three point four percent with PFA and nine point nine percent with drug therapy, a difference of -6.5 percentage points. The EP Edge take at this stage is straightforward. AVANT GUARD shows that first line PFA reduces detected AF burden in selected treatment naive persistent AF patients. The burden signal is real. The efficacy result is statistically strong, but what that means clinically depends on how the endpoint was constructed and what patients actually felt.
Niraj Sharma:Now we need to talk about the study pause. On 10/18/2024, after six neurological events in two fifteen PFA procedures, the data monitoring committee paused enrollment. Two independent neurologists reviewed the events, five were classified as cardio embolic, and one was classified as air embolism associated with the Faradrive deflectable sheath. All were minor strokes, with NIH stroke scale scores below five, and all patients recovered or improved. Several details matter here.
Niraj Sharma:Five of the six neurological events occurred in women. Four of the five embolic strokes occurred in patients with CHADS VASc scores of four or higher. None of the six patients had prior stroke or TIA. None had heart failure or vascular disease. Also important, three of the six were on uninterrupted or near uninterrupted DOAC therapy at the time of the event.
Niraj Sharma:One particularly important case was a 74 year old woman on uninterrupted dabigatran with an intra procedural ACT greater than three fifty seconds who still had an embolic event. That matters because the post pause protocol mandated exactly that kind of best practice anticoagulation and ACT management. In other words, the revised protocol addressed risk but did not eliminate uncertainty. After the pause, protocol version F tightened several key elements. Patients with CHADS VASc scores of four or higher were excluded from PFA randomization and PFA assignment.
Niraj Sharma:Pre procedural imaging was tightened to require TEE or CT within twenty four hours of the procedure. Intracardiac echo alone was no longer sufficient. Anticoagulation had to be uninterrupted for at least four weeks before the procedure. Any missed dose, including the day of the procedure, delayed the case. A CT greater than or equal to three fifty seconds was required before the first PFA application and had to be maintained until all devices were removed from the left atrium.
Niraj Sharma:These changes improved procedural discipline, but they also changed the trial population. The CHADS VAS exclusion removed about a quarter of the eligible pre pause population. Female enrollment decreased. Diabetes and hypertension became less common. Mean CHADS VAS score fell.
Niraj Sharma:So the trial that finished was not exactly the trial that started. The EP Edge take is this: the pause was handled transparently and appropriately, but the post pause safety result applies to a narrower, lower risk population. It should not be generalized automatically to older, higher risk persistent AF patients with more comorbidity. The next question is how did patients fail? This is where the composite endpoint becomes clinically important.
Niraj Sharma:Symptomatic recurrence as the first failure mode was uncommon in both arms and was nearly identical: one point nine percent with PFA and two point nine percent with antiarrhythmic drugs. That is the most important number hiding underneath the headline. Patients did not primarily separate by symptomatic recurrence, they separated by monitor detected asymptomatic recurrence and by treatment escalation. Asymptomatic atrial arrhythmia lasting at least one hour was the first failure mode in thirty point four percent of PFA patients and forty five point six percent of drug treated patients. Non protocol ablation also occurred more often in the drug arm.
Niraj Sharma:About one third of patients assigned to antiarrhythmic drugs eventually crossed over to ablation during the trial. So when people say PFA worked almost twice as well, that statement is technically defensible but clinically incomplete. The main advantage was not that patients felt dramatically better. The main advantage was that continuous monitoring detected less AF. The conventional endpoint in AF ablation trials has often been symptomatic, or documented atrial arrhythmia recurrence of thirty seconds or longer.
Niraj Sharma:AVANT GUARD used a different structure, thirty seconds for symptomatic recurrence but one hour for asymptomatic recurrence. The manuscript reports freedom from symptomatic recurrence alone at ninety percent with PFA versus eighty seven percent with drugs. That is only a three point absolute difference and the confidence interval crosses zero. In plain language, if this trial had been judged only by symptomatic recurrence, it would not have shown a statistically significant difference, but the one hour asymptomatic threshold was prespecified and it was not arbitrary. The rationale comes partly from data suggesting that AF burden measured by continuous monitoring correlates with downstream healthcare utilization and clinical relevance.
Niraj Sharma:The concept is reasonable: more AF burden may reflect more active atrial disease. The supplement also helps. Across different asymptomatic thresholds, from two minutes to one hour, six hours, and twenty four hours, the efficacy gap remained around 20 percentage points, so this was not a cherry picked one hour threshold creating a result out of nothing. The burden signal holds. The EP Edge take is nuanced.
Niraj Sharma:The burden reduction is real and reproducible. But whether that burden reduction translates into better long term outcomes, such as fewer strokes, less heart failure, less dementia, or lower mortality, was not tested in a meaningful way at twelve months. Now let's talk about quality of life. This is one of the most clinically relevant parts of the trial because it connects the statistical endpoint to the patient sitting in front of us. Both groups improved.
Niraj Sharma:The AFEX score improved by 23.3 points with PFA and 19.8 points with antiarrhythmic drugs. Both changes exceed commonly cited thresholds for a clinically meaningful but the between group difference was only 3.6 points, with a confidence interval from -1.8 to plus nine point zero. That means the trial did not show a statistically significant quality of life advantage for PFA over drug therapy at twelve months. The same was true for other patient reported and cognitive outcomes. EQ5D3L did not significantly separate.
Niraj Sharma:Cognitive testing and depression inventory measures did not significantly separate. This does not mean PFA failed. It means the type of benefit detected by the trial was different from the type of benefit many patients expect when they hear that a procedure worked better. The trial shows less AF burden with PFA. It does not show that patients felt substantially better with PFA than with drug therapy inside one year.
Niraj Sharma:That distinction matters in counseling. If a patient says Doctor, will I feel better with ablation than with medication? AVANT GUARD does not prove that answer is yes. If the patient says, Will ablation reduce the amount of AF my heart has, including episodes I do not feel? Then the answer from this trial is yes in the selected population studied.
Niraj Sharma:The trial also did not directly analyze whether patients with lower post treatment AF burden had better quality of life within each arm, so we should be careful not to over interpret the patient perceived data. The EP Edge take: Both strategies improved how patients felt. PFA did more to suppress detected arrhythmia burden. At twelve months, those two facts did not translate into a clearly superior patient reported outcome for PFA. The long game argument for burden remains plausible, but AVANT GUARD does not prove that long game outcome.
Niraj Sharma:Safety deserves a balanced discussion. The PFA serious device or procedure related adverse event rate was five point one percent and met the pre specified performance goal. The serious events included six strokes, all before the protocol pause, two vascular access complications requiring intervention, several pulmonary edema or procedure related heart failure events, one heart block requiring permanent pacemaker, and two cardiovascular events including sinus bradycardia and cardiogenic shock. But the antiarrhythmic drug arm was not benign. Total adverse event burden through twelve months was very similar between groups.
Niraj Sharma:Serious adverse events were twenty one point one percent in the drug arm and twenty one point one percent in the PFA arm. That is a clinically important result. The usual framing that drug therapy is safer, easier, and lower touch is not what this trial showed. Of the patients who started antiarrhythmic drug therapy, about one in five were hospitalized to initiate the drug. Nearly two thirds required at least one electrical cardioversion.
Niraj Sharma:More than one third required dose titration, and about one third eventually crossed over to ablation. Now, the comparator arm also needs scrutiny. Amiodarone was excluded as first line therapy. That is defensible from a guideline and toxicity standpoint, especially if we are talking about initial treatment in many patients. But amiodarone is also the most effective antiarrhythmic drug for persistent AF.
Niraj Sharma:By excluding it, the trial compared PFA against a drug strategy that reflects common practice but not necessarily the strongest possible pharmacologic rhythm control strategy. The drug mix included flecainide, sotalol, dofetilide, and smaller numbers of other agents. For persistent AF, that comparator is clinically realistic in some settings, but it is not the maximal antiarrhythmic strategy. There is also the funding and authorship context. The trial was funded by Boston Scientific, and the analysis was conducted according to the statistical analysis plan.
Niraj Sharma:Several authors were Boston Scientific employees, and many investigators disclosed financial relationships with the company. This does not invalidate the data. Industry sponsored device trials are common in electrophysiology and independent committees reviewed key safety events, but readers should know the funding structure, the disclosure profile, and the fact that patient level data are not being made available for independent re analysis. The EP Edge take: The data are credible, but they should be read with the same rigor we apply to any major industry sponsored device trial. So how should we use AVANT GUARD in practice?
Niraj Sharma:For a treatment naive patient with persistent AF, recently diagnosed, CHADS VASc less than four, preserved ejection fraction, left atrial size 5.5 centimeters, no major comorbidity, and a willingness to accept procedural risk, first line PFA is a reasonable strategy. For that patient, the trial supports saying this: Ablation gives you a higher chance of being free from detected AF at one year compared with a non amiodarone antiarrhythmic drug strategy. It also reduces AF burden. The best estimate from the randomized comparison is about fifty six percent freedom from the composite failure endpoint with PFA versus thirty percent with drugs. But I would avoid telling the patient that PFA simply works twice as well.
Niraj Sharma:That oversimplifies the trial. A better statement is PFA roughly doubles the chance of being completely free from detected AF at one year, but both groups felt similarly better, and both strategies carried meaningful medical risk. For an older patient with CHADS VASc four or higher, prior stroke or multiple comorbidities, the evidence is less direct. These are often the patients in whom rhythm control matters most, but they are also the patients made less visible by the post pause protocol. AVANT GUARD does not prove that first line PFA has the same risk benefit balance in that group.
Niraj Sharma:For women, the discussion should also be honest. Five of the six pre pause neurological events occurred in women, and female sex was an independent predictor of treatment failure in the adjusted model. This is not a reason to deny PFA to women. It is a reason to be transparent, to follow the post pause workflow rigorously, and to acknowledge that sex specific outcomes remain incompletely resolved. The practical counseling script is this: About one in three drug therapy patients eventually required ablation within a year.
Niraj Sharma:About one in five patients in either arm had a serious adverse event over twelve months. Symptomatically, both groups felt better. The advantage of ablation was less detected AF, including AF the patient may not feel. Whether that lower burden improves long term outcomes remains unproven by this trial. That is the balanced message.
Niraj Sharma:It respects the positive result without overselling it. Let's bring this together. AVANT GUARD is a positive trial. It shows that pulsed field ablation, used as initial rhythm control therapy in selected treatment, naive patients with persistent AF reduces detected atrial arrhythmia recurrence and AF burden compared with a non amiodarone antiarrhythmic drug strategy. The trial met both primary endpoints.
Niraj Sharma:The efficacy result was statistically strong. The safety endpoint met its pre specified performance goal. The continuous monitoring burden signal was real and consistent across multiple thresholds. But AVANT GUARD is also only half the story. It does not prove that PFA makes patients feel better than drugs at twelve months.
Niraj Sharma:It does not prove that burden reduction translates into fewer strokes, less heart failure, less dementia, or lower mortality. It does not directly answer what to do in older patients with higher CHADS VASc scores. It does not fully resolve the female sex signal. And it did not test PFA against an amiodarone first strategy. The quick recap is this: AVANT GUARD supports first line PFA as a reasonable option for carefully selected patients with treatment naive persistent AF.
Niraj Sharma:The benefit is strongest for reducing detected AF burden, not for producing a clearly superior symptom or quality of life result at one year. The study pause matters because the trial resumed with a safer, more disciplined, but narrower protocol. Post pause results should be applied to patients who resemble the post pause population, not automatically to every persistent AF patient in clinic. And finally, the antiarrhythmic drug arm was not easy, low touch, or risk free. Many patients needed cardioversion, hospitalization, dose titration and eventual ablation.
Niraj Sharma:So the EP Edge bottom line is this: The headline is real, but the counseling needs nuance. Read AVANT GUARD carefully. Use it clinically. Do not oversell it. That concludes this EP Edge Journal Watch Special HRS 2026 edition on AVANT GUARD.
Niraj Sharma:All references and graphics are available in the LinkedIn newsletter, EP Edge Journal Watch and also on Substack at epedge.substack.com. If you have a clinical case where this framework helps or where it does not fit neatly, I would be very interested to hear your thoughts. EP Edge is built to think alongside its readers and listeners, not simply at them. Thank you again for listening, for reading and for supporting EP Edge Journal Watch. I'm Doctor.
Niraj Sharma:Sharma, take care and I'll see you in the next episode.