Results of pulsed field ablation for complex atrial tachycardia recurring after persistent atrial fibrillation ablation and resistant to prior radiofrequency ablation.

Introduction The efficacy of pulsed field ablation (PFA) for atrial tachycardia (AT) recurrent after radiofrequency ablation (RFA) of initially persistent atrial fibrillation (PeAF) is unknown. These AT sources are often complex/epicardial and located outside the pulmonary veins (PV) / posterior wall of the left atrium (LA). Purpose To present immediate and long-term results of PFA (Farapulse) for ATs that recurred after previous (re)RFA of original (longstanding) PeAF. Methods Between 3/2022 and 7/2025, 178 consecutive patients (65±9 years, 48 women) underwent PFA for recurrent AT in 196 procedures. Patients with combination of recurrent AF and AT were not included. The PFA procedure was overall the 1st, 2nd, 3rd, 4th, and 5th redo procedure in 53, 71, 55, 14, and 3 cases, respectively, all prior procedures were RFA, and the AT was already resistant at the previous procedure. The AT sources were identified with activation and entrainment mapping. Following termination of ongoing AT, arrhythmia non-inducibility tested with atrial pacing up to 300 bpm was the desired procedural endpoint. Follow-up included 7-day ECG monitoring at least at 3, 6, and 12 months and then every 6 months. Results At the procedure onset, the AT was persistent or induced in 130 and 66 cases, respectively. A total of 309 AT types were identified: macroreentry ATs (n=154) included peri-mitral AT (n=89), roof-dependent AT (n=47), and typical flutter (n=18); localized AT sources (smaller reentry/focal) (n=155) originated in the left atrium (n=133), right atrium (n=21) or was undetermined (n=1). At first PFA procedure, AT was terminated in 177/178 (99%) patients, and non-inducibility was achieved in 146 (82%) patients. In 161 patients with follow-up ≥6 (22±9) months, 64% patients remained free from recurrence (≥30 sec); patients with arrhythmia non-inducibility, as compared to those without non-inducibility proved, had better recurrence-free survival (69% vs. 39%, Log Rank p ˂0.0001) (Figures). At the end of follow-up, 86% and 70% patients were in stable SR on/off, respectively off AA drugs. Conclusions The acute efficacy in AT termination with PFA using the pentaspline catheter was nearly absolute, yet freedom from any arrhythmia recurrence was less favourable, and was significantly higher if arrhythmia non-inducibilty was achieved. Final clinical outcome is favourable.