Impact of pulsed field ablation-based pulmonary vein isolation on atrial fibrillation triggers originating from the superior vena cava

BACKGROUND: Non-pulmonary vein (non-PV) atrial fibrillation (AF) triggers, including those originating from the superior vena cava (SVC), are an important source of AF initiation beyond the PVs. OBJECTIVE: To determine the extent to which pulsed field ablation (PFA)-based PV isolation (PVI) modifies atrial arrhythmia inducibility and electrophysiological substrate within the SVC region. METHODS: This prospective observational study evaluated 358 consecutive patients undergoing first-time PVI for AF. A standardized electrophysiological provocation protocol was performed after PVI in all patients. Non-PV AF triggers were defined as premature atrial contractions that directly initiate AF. Arrhythmia inducibility and trigger distribution were compared between PFA and thermal ablation. In a mechanistic sub-study, high-density mapping of the right atrium-SVC (RA-SVC) junction was performed in 40 consecutive patients before and after PFA. RESULTS: Non-PV AF triggers were induced in 7 of 146 patients (4.8%) after PFA and in 22 of 212 (10.4%) after thermal ablation. AF triggers originating from the SVC were significantly less frequent after PFA (1/146, 0.7%) than after thermal ablation (10/212, 4.7%; P = .03). In the mechanistic sub-study, high-density mapping demonstrated conduction delay or block within the RA-SVC region in 33 of 40 patients (83%), with electrical isolation of the SVC observed in 2 patients in whom no intentional SVC ablation was performed. CONCLUSION: These findings suggest an association between PFA and changes in conduction properties at the RA-SVC region, which may influence the distribution of SVC-related AF triggers.