Is pulsed field ablation a valide alternative to radiofrequency in redo ablations? a prospective, multicenter experience

Abstract Background Patients undergoing atrial fibrillation (AF) catheter ablation may require redo procedures as a result of arrhythmic recurrence. The likelihood of arrhythmia relapse is higher in patients with non-paroxysmal AF. Redo procedures might require re-isolation of the pulmonary veins (PVs) and/ or other sites with recovery of conduction, as well as ablation of new extra-PV sites. Pulsed field ablation (PFA) is a non-thermal energy source with cardiac selectivity and limited risk of collateral damage to adjacent tissues. In this perspective, PFA might be an optimal strategy for redo procedures, where ablation of extra-PV sites may be associated with a higher risk of adverse events. Objective to evaluate the feasibility and efficacy of redo atrial fibrillation procedures using a pentaspline PFA catheter. Methods patients enrolled at 3 European centers presenting with an atrial arrhythmia’s recurrence after catheter ablation were divided into three groups based on rhythm at presentation: sinus rhythm (Group-1), atrial flutter/ atrial tachycardia (Group-2), or AF (Group-3) (Figure 1A). A propensity score matching was used to compare the PFA-based vs Radiofrequency (RF)-based redo procedures. Results 117 patients were included in the study (Group-1: 64, Group-2: 18, Group-3: 35). 23 of them (19.7%) had already undergone multiple procedures. The majority of baseline procedures were performed with thermal ablation (91.2%). PV re-isolation was required in 71.9% and 72.2% of Group-1 and -2 patients, respectively. PFA terminated 45.7% of AF cases, which organized as non-cavotricuspid isthmus dependent flutter (mitral, roof dependents and of septal origin) and a case of focal atrial tachycardia from the left atrial appendage. (Figure 2) In 25 cases (21.4%), electroanatomical mapping was needed to define the arrhythmia circuit; entrainment from the pentaspline catheter was used in the remaining patients. One major (0.9%; frontal cerebral hematoma) and five minor complications (three transient ST segment elevations due to transient coronary spasm, two groin hematomas) were documented. Freedom from atrial tachyarrhythmias at 12 months was 78.1% (95% CI 69.2 – 84.6) with a trend towards a lower success rate in Group-3 (Group-1: 85.5%; Group-2: 76.7%; Group-3: 65.1%; p=0.06). (Figure 1B) Propensity matching identified 117 RF patients based on the rhythm at presentation and other baseline characteristics. PFA led to similar arrhythmia freedom compared to RF, but with shorter procedural and dwelling times. Conclusion Redo atrial arrhythmia procedures with a pentaspline PFA catheter was demonstrated to be safe, feasible and effective at one-year-follow up. No clinical differences were observed with RF; nonetheless, PFA procedures were significantly shorter.