Does the efficacy of redo AF-ablation depend on the method used in the index procedure?

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Pulmonary vein isolation (PVI) using cryoballoon (CB) ablation has comparable efficacy and safety compared to radiofrequency ablation (RFA) for first procedure treatment of symptomatic atrial fibrillation (AF). Redo procedures are usually done with RFA, allowing for selective pulmonary vein re-isolation as well as formation of additional lesion sets. It is unclear whether a combination of different ablation methods in the index procedure and the redo procedure provides an efficacy benefit compared to the use of RFA in both procedures. PURPOSE: We aimed to compare the efficacy and procedural characteristics of redo AF-ablation-procedures in terms of the technology used in the first ablation procedure (Cryo vs. RFA). METHODS: We performed a retrospective analysis of our internal AF ablation registry, containing 310 consecutive patients that underwent a second ablation procedure for recurrence of symptomatic AF from November 2019 to August 2022. For 36 patients the method in the first procedure was unknown or a method alternative to RFA or Cryo was used, leaving 274 patients for analysis. Patients were stratified into two groups, based on the technology used in the index procedure (Cryo vs. RFA). Patients underwent follow-up at 3 and 12 months (at 12 months blanking phase recurrences were excluded), either as part of a prescheduled visit or via telephone call to the primary care provider or to the patient. RESULTS: 139 patients underwent the index PVI using RFA vs. 135 patients in which the index procedure was performed with Cryo. Baseline characteristics including sex (37.4% vs. 48.9% female, p=0.055), mean age (68.9 ± 9.7 vs. 68.7 ± 10.9 years, p=0.915), BMI (26,8 ± 4.1 vs. 28.4 ± 4.3 kg/m2. p=0.345), percentage of patients with paroxysmal AF (38.9% vs. 32.6%, p=0.280), arterial hypertension (69.6% vs. 67.4%, p=0.762), beta blocker use (84.1% vs. 80.7% p=0.472), class Ic or III antiarrhythmic drug use on discharge (40.3% vs. 45.9%, p=0.346) and mean left atrial diameter (39.7 ± 5.7 mm vs. 39.9± 5.6 mm. p=0.731) were all similar between groups. In the redo procedures, pulmonary vein reisolation was performed in 85.2% vs. 78.6% (p=0.204) after RFA vs. after Cryo. Additional substrate modifications including lines and defragmentation of low voltage potentials were done in 26.6% vs. 34.1% patients (p=0.179). Procedural duration (147.2 (110-180) vs. 139.0 (100-160) min, p=0.501), fluoroscopy time (12.1 (8.2-17.0) vs. 13.1 (8.2-19.0), p=0,638), and fluoroscopy dose (2525 (1425-3935)vs. 2544 (1356-4840) mGycm2, p=0.806) were comparable between groups. The rates of AF recurrence at 3 month follow-up (27.0% vs. 26.4%, p=0.924) and 12 month follow-up (25.6 vs. 34.5%, p=0.257) were similar between groups. CONCLUSION: In this single center retrospective analysis, there was no difference in efficacy and procedural characteristics of redo AF-ablation-procedures based on the ablation method used in the index procedure.