Background:
Pulmonary vein isolation (PVI) is the cornerstone for patients with both paroxysmal and persistent atrial fibrillation. However, overall efficacy remains limited for persistent AF (persAF). So far, ablation targets and strategies beyond PVI in further procedures have failed to show outcome improvement. Pulsed field ablation (PFA) has recently been introduced as a novel routine ablation technology. Herein, we report the first clinical experience of adjunctive left atrial posterior wall ablation (LAPWA) in patients with persAF using PFA in re-do procedures.

Methods:
In persAF patients, ablation was performed in conscious sedation using a steerable sheath and a pentaspline over-the-wire basket and flower PFA catheter. In all patients, pre-ablation high-density bipolar voltage 3D map (Carto 3D) was performed. After fluoroscopic guided PVI, the pentaspline catheter was localized in the 3D mapping system. The posterior wall was then directly ablated with the multispline PFA in a flower configuration, with guidance from the interim voltage map (Figure 1). The catheter was positioned in overlapping fashion across the posterior wall such that there was redundant coverage of all sites. All patients received 4 applications per side in a 2-by-2 fashion at 2.0 kV. Following ablation, a high-density 3D map and pacing for final lesion confirmation and documentation of bidirectional block were performed. Procedural parameters, acute success, in-hospital safety and arrhythmia recurrence were assessed.

Results:
17 patients were enrolled between September 2021 and November 2022. The mean age was 68±8 years (70% male). The mean CHA2DS2-VASc-Score was 3±1. Time since first diagnosis of AF was 72±46 months. The mean number of previous procedures was 3±1. Acute PVI and LAPWA were 100% acutely successful with the multispline PFA catheter alone. The median skin-to-skin procedural time was 160±62 min (including a 47±10 min for pre and post ablation voltage mapping). Left atrial dwell time of the PFA catheter was 46±19 min Fluoroscopy time and dose area product were 24±9 min and 13±13 Gy.cm2, respectively. All patients tolerated this approach without procedural interruption. There was no major periprocedural complication in any of the patients. There were no instances of stroke or TIA, pericardial tamponade, atrioesophageal fistula or phrenic nerve injury during follow-up. After a follow-up of 163±105 days, 11/17 (64%) patients remained in a stable sinus rhythm.

Conclusions:
PFA is a novel ablation modality for PVI. In patients with persAF requiring ablation beyond PVI, LAPWA using PFA seems to be a safe and feasible approach with promising results in a small number of patients. Larger trials are warranted to determine long-term efficacyand safety outcomes.



Figure 1: LAPWA in PA-view, pre - and post ablation