Superior vena cava epicardial adipose tissue predicts unintended low-voltage changes after pulsed field ablation

Background Pulsed-field ablation (PFA) is a minimally thermal technique for atrial fibrillation (AF) that induces irreversible electroporation with relative myocardial selectivity. However, unintended collateral injury to adjacent structures, including the superior vena cava (SVC) and right atrium (RA), has been increasingly recognized. Objective We aimed to characterize collateral electrophysiological effects of PFA on the SVC and RA septum, identify associated anatomical factors, and assess the relationship between low-voltage regions and the sinus node. Methods In this single-center prospective cohort study, 95 patients undergoing PFA for AF using three PFA systems (Farapulse, Varipulse, or PulseSelect) were evaluated. Pulmonary vein isolation (PVI) with or without posterior wall isolation (PWI) was performed. Unintended electrophysiological changes were defined as dense low-voltage change (<0.1 mV). Anatomical factors, including superior vena cava epicardial adipose tissue (SVC-EAT) volum, were analyzed using multivariate logistic regression. Results RA septal/SVC low-voltage changes were observed in 51.6% of patients and were independently associated with smaller SVC-EAT volume. In an exploratory analysis of SVC low-voltage changes (40.0% incidence), older age and smaller SVC-EAT volume were independently associated with these findings. The minimum distance between an SVC low-voltage region and the sinus node was 0.5 mm. Conclusion Unintended collateral electrophysiological changes in the SVC and RA septum were frequently observed after PFA. Smaller SVC-EAT volume was independently associated with SVC low-voltage changes, suggesting that local anatomical characteristics may influence collateral electrophysiological effects. These findings provide hypothesis-generating insights into anatomical factors associated with unintended electrophysiological changes after PFA, although their clinical significance remains uncertain.