Association between body mass index and results of cryoballoon ablation in Korean patients with atrial fibrillation: an analysis from Korean Heart Rhythm Society Cryoablation registry

Background Pulmonary vein isolation using cryoablation is effective and safe in patients with atrial fibrillation (AF). Although both obesity and underweight are associated with a higher risk for incident AF, there is limited data on the efficacy and safety following cryoablation according to body mass index (BMI) especially in Asians. Methods Using the Korean Heart Rhythm Society Cryoablation registry, a multicenter registry of 12 tertiary hospitals, we analyzed AF recurrence and procedure-related complications after cryoablation by BMI (kg/m2) groups (BMI<18.5, underweight, UW; 18.5-23, normal, NW; 23-25, overweight, OW; 25-30, obese Ⅰ, OⅠ; ≥30, obese Ⅱ, OⅡ). Results A total of 2,648 patients were included (median age 62.0 years; 76.7% men; 55.6% non-paroxysmal AF). Patients were categorized by BMI groups; 0.9% UW, 18.7% NW, 24.8% OW, 46.1% OI, and 9.4% OII. UW patients were the oldest, and had least percentage of non-paroxysmal AF (33.3%). During a median follow-up of 1.7 years, atrial arrhythmia recurred in 874 (33.0%) patients (incidence rate, 18.9 per 100 person-year). After multivariable adjustment, the risk of AF recurrence was higher in UW group compared to NW group (adjusted hazard ratio, 95% confidence interval; 2.55, 1.18-5.50, p=0.02). Procedure-related complications occurred in 123 (4.7%) patients and the risk was higher for UW patients (odds ratio, 95% confidence interval; 2.90, 0.94-8.99, p=0.07), mainly due to transient phrenic nerve palsy. Conclusion UW patients showed a higher risk of AF recurrence after cryoablation compared to NW patients. Also, careful attention is needed on the occurrence of phrenic nerve palsy in UW patients.