Pulsed Field Ablation Systems for Atrial FibrillationIbrahim Hasan MD, Marwan M. Refaat, MDDivision of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, LebanonRunning Title: PFA Systems for AFWords: 568 (excluding the title page and references)Keywords: Ablation, Pulsed Field, Atrial Fibrillation, cardiac arrhythmias, cardiology, cardiovascular diseasesFunding: NoneDisclosures: NoneCorresponding Author:Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP, FRCPTenured Professor of MedicineTenured Professor of Biochemistry and Molecular GeneticsMember, Division of Cardiology/ Section of Cardiac ElectrophysiologyDirector, Cardiovascular Fellowship ProgramAmerican University of Beirut Faculty of Medicine and Medical CenterPO Box 11-0236, Riad El-Solh 1107 2020- Beirut, LebanonUS Address: 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USAOffice: +961-1-350000/+961-1-374374 Extension 5353 or Extension 5366 (Direct)The field of atrial fibrillation (AF) ablation is witnessing a transformative shift with the pulsed field ablation (PFA) technologies. PFA, a non-thermal energy source that selectively targets myocardial tissue while sparing adjacent structures such as the esophagus and phrenic nerve, holds promise in addressing the limitations of conventional thermal ablation techniques. The recent multicenter registry study comparing the FARAPULSE™ pentaspline catheter and the PulseSelect™ circular catheter provides valuable real-world data on procedural characteristics, acute efficacy, and safety of these commercially available PFA systems.This registry, encompassing over 400 patients from six international centers, demonstrated 100% acute pulmonary vein isolation (PVI) success in both cohorts, confirming the robust efficacy of PFA in AF ablation. Notably, procedural times were significantly shorter with the pentaspline catheter (median 36.0 minutes) compared to the circular catheter (median 49.0 minutes, p < 0.001). These findings align with earlier studies, such as the ADVENT trial [1], and a meta-analysis by Aldaas et al [2], which highlighted the procedural efficiency of PFA over traditional thermal ablation techniques. The shorter procedure times observed with the pentaspline catheter may reflect its design optimized for rapid and efficient PVI, though operator experience and workflow factors likely contribute as well. Both systems exhibited low rates of major adverse events, with only 0.5% of patients experiencing a stroke and 0.2% suffering a serious vascular complication. Importantly, minor vascular access site complications were more frequent in the pentaspline group (11.9% vs. 1.1%, p < 0.001), underscoring the need for meticulous vascular access techniques in PFA procedures.The authors appropriately acknowledge several limitations inherent to the study’s observational, non-randomized design. Missing data, potential underreporting of adverse events, and variations in operator experience and institutional protocols across centers could influence outcomes. While most patients underwent standardized post-procedural monitoring and at least one follow-up visit, the possibility of undetected events cannot be fully excluded. Selection bias, although minimized by system availability, remains a potential confounder. Importantly, the study reports only acute procedural outcomes, leaving long-term efficacy, lesion durability, and arrhythmia recurrence unaddressed. While prior studies, including the PULSED AF pivotal trial [3] and data from the MANIFEST-PF Registry [4], suggest promising long-term outcomes for PFA comparable to thermal ablation, randomized controlled trials comparing different PFA systems over extended follow-up periods are needed to establish their relative benefits.This study represents the first head-to-head, multicenter comparison of two commercially available PFA systems in a real-world setting. Despite procedural differences, both systems achieved excellent acute outcomes with low complication rates. The multicenter design, while introducing heterogeneity, enhances the generalizability of findings and provides a broader perspective on current clinical practice. Looking ahead, several critical questions remain: Will the procedural efficiency advantages of the pentaspline catheter translate into meaningful improvements in long-term arrhythmia-free survival? Can the lower incidence of vascular complications with the circular catheter be maintained in larger, diverse patient populations? Moreover, as PFA technology evolves, how will novel catheter designs, lesion assessment tools, and mapping strategies influence clinical outcomes?The findings of this comparative registry study reinforce the safety and efficacy of PFA as an emerging standard for AF ablation. Both the FARAPULSE™ and PulseSelect™ systems demonstrate high procedural success and low major adverse event rates, though procedural characteristics and minor complication profiles differ. Further research—particularly prospective, randomized trials with long-term follow-up—will be critical to define the optimal role of each PFA system and solidify PFA’s position in the therapeutic armamentarium for atrial fibrillation.