Study Population
This is a non-randomized single center retrospective study of AF patients undergoing catheter ablation at Fujita Health University from January 2015 to September 2019. Written informed consent was obtained from all patients undergoing catheter ablation for AF. Among them, patients on uninterrupted OAC who underwent brain MRI within 2 days after the catheter ablation were enrolled. Baseline demographics/clinical information (AF type, past history, comorbidities, medications, etc.) was obtained; CHADS2 and CHA2DS2-VASc scores were calculated. Laboratory examinations (creatinine and brain natriuretic peptide, etc.) and transthoracic echocardiography (ejection fraction and left atrial dimension, etc.) were performed before catheter ablation. Transesophageal echocardiography (TEE) was performed one day before the procedure, and patients with left atrial appendage thrombus detected by TEE were excluded. Patients with creatinine clearance (CrCl, calculated by Cockcroft-Gault formula) <15 mL/min and those on hemodialysis were excluded from the study. Patients with mechanical valves was also excluded.