Direct Atrial Fibrillation Termination During Pulsed Field Ablation: Association With Intracardiac Cycle Length

BACKGROUND: Pulsed field ablation (PFA) enables rapid and tissue-selective pulmonary vein isolation (PVI). However, the electrophysiological determinants of direct atrial fibrillation (AF) termination during PFA remain unclear. OBJECTIVE: To investigate the clinical and electrophysiological characteristics associated with direct AF termination during PFA-guided PVI. METHODS: This prospective, single-center study included 72 patients with persistent AF undergoing PFA-based PVI. Intracardiac tachycardia cycle length (TCL) was measured at each pulmonary vein before ablation. Patients were classified into termination and no-termination groups, and clinical and electrophysiological parameters were compared. RESULTS: Direct AF termination occurred in 14 patients (19.4%), most frequently at the right superior pulmonary vein (RSPV) (n = 8) , followed by the Left superior pulmonary vein (LSPV) (n = 6). Patients with termination had shorter AF duration, smaller left atrial size, and lower NT-proBNP levels. TCL at the superior pulmonary veins, particularly the RSPV, was significantly longer in the termination group, while no differences were observed at other pulmonary veins. At 3 months, AF recurrence tended to be lower in the termination group, although the difference did not reach statistical significance. CONCLUSION: Direct AF termination during PFA is associated with favorable clinical characteristics and localized TCL prolongation in the superior pulmonary veins, suggesting their important role in AF maintenance rather than a purely random procedural effect.