Finerenone After Catheter Ablation to Reduce Atrial Fibrillation Recurrence

Atrial fibrillation (AF) is a common heart rhythm disorder associated with stroke, heart failure, and increased mortality. Catheter ablation with pulmonary vein isolation (PVI) is an effective rhythm-control strategy, but 20-30% of patients experience AF recurrence within one year. Finerenone, a nonsteroidal mineralocorticoid receptor antagonist with anti-inflammatory, antifibrotic, and metabolic effects, was associated with a lower incidence of AF in prior large trials, and preclinical studies suggest it promotes "browning" of adipose tissue and improves epicardial adipose tissue (EAT) characteristics. This single-center, randomized, investigator-blinded pilot trial will enroll 40 patients undergoing first-time catheter ablation for AF. After successful PVI, participants will be randomized 1:1 to receive finerenone or usual care for 12 months. The primary endpoint is AF recurrence (any atrial arrhythmia episode lasting 30 seconds or longer) after a 90-day blanking period, within 12 months post-ablation. Mechanistic endpoints include EAT remodeling assessed by cardiac computed tomography and echocardiography, and circulating uncoupling protein-1 (UCP1) levels as a biomarker of adipose tissue browning. The investigators hypothesize that finerenone will lower AF recurrence after ablation, partly through modulation of EAT function.

Inclusion Criteria: * Age 18-80 years * Atrial fibrillation scheduled for first-time catheter ablation (pulmonary vein isolation) * Estimated glomerular filtration rate (eGFR) \>=25 mL/min/1.73 m2 * Serum potassium \