Impact of pre-existing left atrial appendage occluder on catheter ablation of atrial fibrillation

Background Patients with drug-refractory atrial fibrillation (AF) and pre-existing left atrial appendage occluder (LAAO) device may need pulmonary vein isolation (PVI). In this pioneer study, we investigated the impact of pre-existing LAAO on AF substrates and outcomes of PVI. Methods From our AF registry, 65 drug-refractory patients with LAAO (72.1±11.4 years old; CHA 2 DS 2 -VASc score 3.7±2.1) were included for PVI. A balanced control group with 124 patients without LAAO receiving PVI (70.9±10.2 years old, CHA 2 DS 2 -VASc 3.6±1.9) were included for comparison. Results We found PVI is feasible in patients with AF with pre-existing LAAO without new peridevice leak. Two patients with LAAO and one without LAAO had stroke during the procedure (2/65 vs 1/124, p=0.272). Complete isolation of left-sided PVs might not be achieved if the device covered the ridge joining the left atrial (LA) appendage to the body of LA. Local electrogram could be detected over LAAO and there was propagation of conduction over the occluder either under sinus rhythm or under atrial arrhythmia. LAAO might modulate LA substrate and induce peridevice fibrosis, peridevice LA flutter and complex fractionate atrial electrogram. The AF recurrent rate at 1 year was similar between the two groups (9.2% vs 8.8%). Conclusions This pioneer study first showed impacts of LAAO on LA substrate and PVI procedure.