Characteristics of Atrial Tachycardia Recurrence After Pulsed Field Ablation: Insights From Repeat Ablation Procedures.

BACKGROUND: Pulmonary vein isolation (PVI) using pulsed field ablation (PFA) for atrial fibrillation (AF) is becoming increasingly widespread. However, characteristics of atrial tachycardia (AT) recurrence after PFA remain unclear. We aimed to investigate characteristics of AT recurrence in comparison with AF recurrence after PFA-based PVI. METHODS: We analyzed 60 consecutive patients who underwent repeat ablation for recurrent atrial tachyarrhythmia after initial PVI alone performed with a pentaspline PFA system. Patients were classified into an AT group (at least one AT episode before repeat ablation) and an AF group (AF recurrence only). Baseline characteristics, pulmonary vein (PV) reconnections, and recurrence-free rate after repeat ablation procedure were assessed. RESULTS: The AT group consisted of 34 patients (57%). In the multivariate analysis, absence of PV reconnections was independently associated with AT recurrence (p = 0.037). All mappable ATs were macro-reentrant circuits and none were directly related to PVs. Recurrence-free rate after repeat ablation did not differ between AT and AF groups (p = 0.277). However, patients presenting in AT at the beginning of the repeat procedure had the most favorable outcomes, whereas those in AF had the poorest (p = 0.042). CONCLUSIONS: After PFA-based PVI, AT recurrence was characterized by lower PV reconnection rates and macro-reentrant circuits remote from the PVs, whereas AF recurrence was more frequently associated with PV reconnections. While overall outcomes after repeat ablation were comparable, baseline rhythm at the repeat procedure was associated with prognosis, underscoring the importance of tailored mapping and ablation strategies after PFA.