Background: Patients with persistent atrial fibrillation (persAF) show higher recurrences rates after catheter ablation (CA) than paroxysmal AF patients (PAF). Therefore, sole re-isolation of the pulmonary veins (PVI) might be insufficient in patients with persAF, undergoing re-ablation. Additional substrate modification, including left atrial posterior wall isolation (LAPWI) may improve rhythm control. However, achieving durable lesions may be difficult and the proximity to the esophagus needs to be considered when performing LAPWI with current ablation technologies. 

Objective: This study sought to investigate efficacy and safety of LAPWI performed by pulsed-field-ablation (PFA) in patients undergoing re-ablation for persAF. 

Methods: Consecutive patients undergoing re-ablation for persAF after prior catheter ablation were prospectively enrolled in the study. All patients underwent PFA-guided catheter ablation with the use of a 3D mapping system in two German centers.

Ablation strategy for the re-ablation procedure included 1) re-PVI, if necessary, and 2) LAPWI and/or additional substrate modification. Esophageal endoscopy was performed at the discretion of the operator. Patients were followed up by telephone interview and routine Holter-ECGs.

Results: In total, two centers enrolled nineteen PersAF patients into the study. Patients underwent 3 ± 1 prior catheter ablation procedures for AF.  Patients’ mean age was 65 ± 18 years, 17 of 19 patients were male (89.5%) with a median CHA2DS2-VASc Score of 2 (q1-q3:1-4). 

In this study, PFA-guided CA with a procedure duration of 113 ± 35.2 mins and a fluoroscopy time of 14.0 ± 5.7 mins was performed in all patients. In 15 patients, all PVs were isolated (15/19, 78.9%). PV-reconnections warranting re-PVI was found in 7 PVs of 4 patients (4/19, 21%). In 60% (9/15) of patients with all PVs isolated, PFA was applied at the PV ostia to extent the antral ablation line and/or to ablate ostial signals.

Successful LAPWI with PFA was performed in all patients (19/19; 100%). Additional left atrial substrate modification with PFA was conducted in 11 patients (58%; roof line (n=11), anterior line (n=9), mitral isthmus line (n=2)).

There was one minor groin complication (small AV-fistula not requiring treatment). No esophageal lesion was found in 10 patients that underwent post-procedural esophageal endoscopy. 

Conclusion: Left atrial posterior wall isolation guided by pulsed field ablation is feasible and safe in patients undergoing re-ablation for persistent atrial fibrillation.