Pulmonary vein and posterior wall isolation and mitral isthmus block with radiofrequency vs electroporation: comparing a classic to a novel technique for the ablation of persistent atrial fibrillation

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. INTRODUCTION: Persistent atrial fibrillation (PerAF) ablation continues to be a challenge due to the wide variety of approaches and a high arrhythmia recurrence. In our center, the usual strategy for PerAF ablation comprises posterior wall isolation (PWI) and mitral isthmus block (MIB) in addition to pulmonary veins isolation (PVI), with alcoholization of the Vein of Marshall (VoM) if possible. Pulsed-field ablation (PFA) has emerged as a novel and promising source of energy for AF ablation, having proved its feasibility and safety for PVI. However, there is no evidence in terms of feasibility and safety about a combined strategy of PVI, PWI and MIB. PURPOSE: Our aim was to assess the feasibility and safety of PVI, PWI and MIB with PFA for PerAF ablation, and compare it to the same approach carried out with radiofrequency (RF) +/- alcoholization of the VoM, in terms of procedural parameters, acute success and complications rate. METHODS: All patients who undergone PerAF ablation with PFA and RF between November 2021 and September 2022 were consecutively and retrospectively included in the study. Demographic data, procedural data, rate of acute access (in achieving isolation or block of the targeted substrates) and complications rate were collected. RESULTS: Ninety patients with PerAF ablation were included (45 with the classic approach [RF ± VoM] and 45 with PFA). No differences were found in mean age and gender (67.0±9.1 vs 67.0±10.02 y.o, p=0.96 and 26.6% vs 24.4% of women, p=0.8). No differences were found with regard to previous cardiopathy or other comorbidities. There were also no differences in left atrial volume (157±41.1vs145±54.8ml, p=0.26). As for the procedure, the PFA group had shorter procedural time (119.8±26.3vs 84.1±20.0 min, p=0.00) but longer fluoroscopy time (17.8±6.9vs23.6±6.7 min, p=0.0002) and higher fluoroscopy dose (36.1±25.3vs67.3±84.7 Gy.cm2, p=0.02). No differences were found in the acute success rate to achieve PVI (100% in all), PW isolation (97.7%vs100%, p=0.31) or mitral isthmus block (97.7%vs100%, p=0.31) between RF±VoM and PFA groups, respectively. Of note, among the patients in AF rhythm at the procedure, the rate of reversion to sinus rhythm during ablation was much higher in the PFA group (7.14% vs 77.7%, p=0.00), with a lower rate of cardioversion (92.8% vs 22.2%, p=0.00) during the procedure. No significant differences were found with regard to the number of complications (13.3% [6 cases] in the RF±VoM group vs 6.6% [3 cases] in the PFA group, p=0.27). CONCLUSIONS: PFA shows a good feasibility and safety profile for PVI, PWI and MIB with shorter procedural time and higher rate of conversion to sinus rhythm during ablation compared to the classic strategy with radiofrequency.