Comparison of pulsed field ablation and thermal ablation for repeat procedures after failed prior thermal ablation for atrial fibrillation
Authors: Baskaralingam A , Kueffer T , Maurhofer J , Madaffari A , Thalmann G , Kozhuharov N A , Galuszka O , Rehman S , Servatius H , Haeberlin A , Noti F , Tanner H , Roten L , Reichlin T 
Published: May 2024

Abstract

Background
Procedural efficiency and long-term clinical outcome after a first pulmonary vein isolation (PVI) for atrial fibrillation (AF) with pulsed-field ablation (PFA) has recently been reported to be non-inferior compared to radiofrequency ablation (RFA) and cryoballoon ablation (CBA). Studies comparing PFA and RFA for a first redo procedure in patients with failed prior thermal PVI are lacking.

Purpose
We sought to compare procedural efficiency and 1-year success rate (i.e maintenance of sinus rhythm) between PFA and RFA in patients undergoing a first redo procedure due to recurrence of atrial tachyarrhythmias after a prior thermal PVI.

Methods
Patients with recurrences after a 90-day blanking period following an index PVI with either RFA or CBA referred for a first redo ablation were enrolled. All redo procedures were done using a 3D electro-anatomical mapping to identify PV reconnections and guide repeat PVI by either PFA or RFA. In cases of incomplete or ostial isolation, the PFA group was treated using the standard 8-applications per vein while the CLOSE protocol was used for segmental PVI completion in the RFA group. Extra-PV lesion sets were added at the discretion of the treating physician. Patients were followed with 7d-Holter ECGs 3, 6, and 12 months after reablation. Recurring arrhythmias were categorized as persistent AF, paroxysmal AF, or atrial flutter. Secondary endpoints were periprocedural complications, total ablation time, radiation time and exposure.

Results
A total of 220 patients (median age 67 [IQR 58-74] years, 64% male, 64% persistent AF) were enrolled and equally treated with PFA or RFA (110 in both groups). There were no statistically significant differences in the clinical characteristics at baseline. Procedure time was shorter in the PFA group (95 vs. 122 minutes, p=0.001) whereas radiation time and dose were higher in the PFA group (17.0 vs. 6.4 minutes, p=&lt;0.001 and 4.9 vs. 2.2 Gycm2, p=&lt;0.001). Additional posterior wall ablation (PFA) or roof line (RFA) was performed predominantly in the PFA group (61 patients, 55.5 %) and in 5 patients (4.5 %) in the RFA group (p=0.001). Major complications occurred in 3 patients in the PFA group and in 1 patient in the RFA group (see Picture 2). Freedom from arrhythmia in Kaplan-Meier analysis 12 months after the reablation was 61% (CI 50-74%) in the PFA group and 59% (CI 49-71%; log-rank test p=0.81). No differences in outcomes were observed in the pooled group between paroxysmal AF (60%, CI: 50-72%) and persistent AF (61%, CI: 51-73%, p=0.64). Recurrence of organized atrial tachycardia was more common in the PFA group (p=0.018)

Conclusion
In patients undergoing a first redo procedure after a first round of thermal PVI and with recurrence of atrial tachyarrhythmia, PFA for reablation resulted in shorter procedure times compared to RFA despite more frequent posterior wall ablation. Long-term arrhythmia-free survival after the redo procedure was similar in both groups.Kaplan-Meier analysis of redo proceduresProcedure and outcome data