Left atrial debulking with pulsed field ablation in persistent atrial fibrillation

Catheter ablation (CA) for the treatment of persistent atrial fibrillation (PersAF) represents a challenge since the outcome of pulmonary vein isolation (PVI) in this population is poor. The use of a pentaspline pulsed field ablation (PFA) catheter to target PV and left atrial (LA) posterior wall (LAPW) to treat PersAF has already been described.

We aimed to determine if the extension of the LA ablation area beyond PV and LAPW is associated with improved rhythm outcome in PersAF patients.

Consecutive PersAF patients undergoing CA with PFA were enrolled. Ablation strategy was chosen according to operators' preference. All patients received post-ablation high density voltage mapping for validation. Primary efficacy endpoint was defined as any atrial tachyarrhythmias (ATAs) recurrence after the 2-month blanking period. Periprocedural adverse events were recorded as the primary safety endpoint.

One hundred eleven (n=111) consecutive PersAF patients, treated with PFA of PVs and LAPW (Box-only group [BO], n = 51) or with extensive PFA of the LA (Debulking group [DB], n = 60) were enrolled. Patients in the DB group were younger (64.7±8.0 years) than patients in the BO group (68.0±7.8 years, p=0.014). Echocardiografic baseline characteristics were similar (LA volume was: DB group 99.6±28.3 ml vs BO 96.2±35.3 ml; p=0.459; left ventricular ejection fraction was: DB group 57.5% [Q1-Q3: 52.7-62.9] vs BO group 55.0 % [Q1-Q3: 52.7-62.9]; p=0.459). DB group patients had shorter PersAF duration (DB group 24 months [Q1-Q3: 12.0-48.5] vs BO group 26.0 months [Q1-Q3: 15.0-54.0], p=0.014). Patients in the BO group received PVI and LAPW ablation (area from the upper end of the superior PV to the lower end of the inferior PV). All patients in the DB group received adjuntive ablation of the inferior wall towards the atrioventricular groove; among those, 44 patients underwent anterior roof ablation. Among these latter 44 patients, in 5 cases the lesion set was extended to the mitral isthmus, and in 2 cases to the posterior interatrial septum.

There was no difference in the overall procedure duration (DB group 90 [Q1-Q3: 90-120] minutes vs BO group 95 [Q1-Q3: 87.5-120] minutes; p=0.849.) No differences in major periprocedural complications were recorded in both groups (one case of severe pericardial effusion plus one case of severe anemia due to hemolysis in DB group vs one major vascular access complication in BO group; p=0.465). After a median follow up of 411 days, patients in the DB group were less likely to show ATAs recurrences (recurrence rate DB group 23% vs BO 41%; p=0.044). No differences in the antiarrhytmic drug use rate was found between patients with recurrences (78.8% in DB group vs 71.4% in BO group, p=0.635).

PVI plus extensive left atrial debulking showed better rhythm outcome compared to a PVI plus LAPW ablation in PersAF patients. No differences in periprocedural complications was found among groups.

examples of post-CA voltage mapping