Pulsed‐Field Ablation: The Future Gold Standard for Mitral Isthmus Ablation?

We read with great interest with the paper published by Valderrábano et al. about the venous ethanol infusion in the ablation of atrial fibrillation (AF) [1]. The authors are to be commended for elucidating the technique of Vein of Marshall (VOM) ethanol ablation, which has undoubtedly revolutionized our approach to achieving a durable mitral isthmus (MI) block, particularly in persistent AF. The emergence of pulsed-field ablation (PFA) as a novel, non-thermal energy source prompts a re-evaluation of this landscape. Recent studies have demonstrated that PFA alone can achieve acute bidirectional block of the MI with success rates exceeding 90%. This remarkable efficacy, coupled with its inherent safety profile, positions PFA not merely as a complementary tool but as the prospective successor to VOM ethanol ablation. We posit that PFA has the potential to fully replace ethanol infusion for several compelling reasons. VOM ethanol ablation, while effective [2], is a technically demanding procedure with a significant learning curve. It requires specialized equipment, meticulous cannulation, and carries nonnegligible risks such as dissection, perforation, and alcohol-induced coronary artery spasm. In contrast, PFA can achieve similar—if not superior—acute success rates using standard, single-shot catheter technology. This dramatically simplifies the procedure, reduces operator dependency, and has the potential to make durable MI block accessible in a broader range of electrophysiology laboratories. PFA's tissue selectivity, which spares the coronary arteries, esophagus, and phrenic nerves, is its most transformative advantage. The avoidance of ethanol, an inherently cytotoxic agent, eliminates the risks associated with its extravasation or inadvertent injection. As the collective experience with PFA grows, its safety superiority over the chemical ablation of VOM is becoming increasingly evident, making it a more desirable option for both patients and operators [3]. While long-term data are still maturing, the fundamental mechanism of PFA suggests it may yield more durable lesions. PFA induces irreversible electroporation, leading to cardiomyocyte apoptosis within a well-defined area, which may promote a more favorable and stable fibrotic healing response compared to the necrotic and inflammatory process caused by ethanol. The high acute success rate of 90%+ with PFA alone indicates that it can effectively overcome many of the epicardial barriers traditionally cited as the rationale for ethanol. As catheter designs evolve to ensure deeper and more contiguous lesion formation, the need for adjunctive epicardial chemical ablation will likely diminish further [4]. In conclusion, while VOM ethanol ablation has been a groundbreaking technique that illuminated the importance of the epicardial substrate, the advent of PFA represents a paradigm shift. Its combination of high efficacy, exceptional safety, and procedural simplicity makes it a formidable technology. With further technological refinement and accumulating long-term outcomes data, we believe PFA is poised to become the stand-alone gold standard for MI ablation, ultimately replacing the need for venous ethanol infusion. The author declares no conflicts of interest.