Beyond a Threshold: Body Mass Index as a Continuous Driver of Repeat Intervention After Atrial Fibrillation Cryoablation.

BACKGROUND: Obesity is a recognized risk factor for atrial fibrillation (AF) and may adversely affect rhythm outcomes after catheter ablation. However, the relationship between body mass index (BMI) and clinically relevant recurrence after cryoballoon pulmonary vein isolation (PVI) remains incompletely defined. METHODS: We analyzed a retrospective single-center registry of patients undergoing index cryoballoon PVI for AF between January 2018 and January 2024. Patients with documented BMI between 18.5 and 40 kg/m2 were included. The primary endpoint was rehospitalization for rhythm intervention within two years after index ablation, defined as repeat left atrial ablation or electrical cardioversion after a 90-day blanking period. Time-to-event analyses were performed using Kaplan-Meier estimates, log-rank testing, and Cox proportional hazards regression adjusted for age, sex, and AF type. RESULTS: A total of 2475 patients were included. Median BMI was 27.1 kg/m2; 718 patients had BMI < 25 kg/m2, 1081 had BMI 25-29.9 kg/m2, and 676 had BMI ≥ 30 kg/m2. During two-year follow-up, 402 primary endpoint events occurred, including 221 repeat ablations and 181 electrical cardioversions. Kaplan-Meier analysis showed a significantly lower event-free rate in overweight and obese patients compared with normal-weight patients. In the adjusted Cox regression, BMI was independently associated with the primary endpoint, with a 3% relative risk increase per 1 kg/m2 BMI increment. No significant interaction was observed for age, sex, or AF type. CONCLUSION: Elevated BMI is independently associated with increased risk of clinically relevant rhythm-related rehospitalization after cryoballoon PVI. These findings support the integration of weight management into comprehensive AF ablation care.