Clinical data collection
All patient data were retrospectively obtained from our CA database. Age, sex, preoperative and postoperative anti-arrhythmia drug (AAD) use, CHADS2 score, CHA2DS2-VASc score, body mass index, left ventricular ejection fraction, left atrium (LA) size, serum creatinine, hematocrit, and brain natriuretic peptide of each patient were examined. We reviewed all surgical reports and electrophysiological findings.