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.