Atrial fibrillation re-ablation: a comparative analysis of the efficacy of initial PVI procedures

Abstract Introduction Atrial fibrillation (AF) catheter ablation based on pulmonary vein isolation (PVI) has steadily gained evidence for establishing rhythm control. In cases of AF relapse, a redo procedure may be beneficial to maintain sinus rhythm. Purpose To describe the mapping analysis and ablation strategies adopted during AF redo procedures and to compare the efficacy in PVI of the different ablative modalities used for the first procedure. Methods Single-center, retrospective study of patients submitted to AF redo ablation from 2015 to November 2024. Redo procedures mapping was performed with high-density electroanatomic systems (Carto, Ensite, Rhythmia). Ablation strategy was the following: in the cases of PV reconnection, PV isolation was attempted, non-PV trigger were mapped and ablated, and substrate modification with linear lesion deployment or scar homogenization, was performed at operator description in case of extensive left atrial substrate. Effectiveness of prior ablation technique in sustained PVI was evaluated with SPSS (Version 29.0.2.0). Results A total of 264 patients were included (70% male, 62±11 years old, 55.3% paroxysmal AF:). First ablation procedure was performed with Point-by-Point RF in 100 (38%) pts, PVAC in 64 (25%) pts, cryoablation in 96 (37%) pts, pulsed field ablation in 3 pts and surgical ablation in one. Substrate mapping revealed complete PV isolation in only 12.9% of the pts and reconduction of at least one PV in the large majority of pts (n=230, 87%). Left atrium areas of low-voltage areas were identified in 31% of the pts, more frequently in the anterior wall (64%). Of these, an additional substrate modification was done in 83%. Non-PV triggers were mapped in 13 pts (9 in left atrium and 4 in right atrium). Compared to other techniques, cryoablation, was more effective in achieving sustained PVI, showing higher rates of persistent PVI of 2 or 3 PVs (p=0.008) – fig 1, although with no difference in the pts that had all the PVs isolated– fig 2. Additionally, cryoablation was associated with a higher percentage of persistent left superior, left inferior and right inferior PV isolation (p=0.038, 0.001 and 0.003, respectively), compared to PVAC and Point-by-Point RF, with no differences regarding left pulmonary trunk (Fig 1). On a detailed analysis of each ablation technique, it was observed that with cryoablation the right superior PV was the least likely vein to be isolated during the redo procedure (p=0.001), whereas no pattern was observed with other modalities. Conclusion Most of the patients submitted to AF redo procedures showed PV reconnection, highlighting the need for a more efficient technique for first PVI. When compared to other ablation modalities, cryoablation showed higher rates of PV isolation.