Study population
We retrospectively analyzed 259 consecutive patients who underwent open-heart surgery with concomitant surgical AF ablation in a tertiary academic referral center between October 2008 and March 2016. All patients undergoing open-heart surgery were prospectively registered in our institutional database, which contains demographics, preoperative risk factors, echocardiographic characteristics, operative details, and postoperative complications according to the established Society of Thoracic Surgeons National Adult Cardiac Surgery Database (STS ACSD) definition.8 Chronic kidney disease was defined as an estimated glomerular filtration rate (eGFR) of <60 ml/min/1.73 m2 using the Modification of Diet in Renal Disease equation. We calculated the EuroSCORE II using an online calculator.9
All patients had follow-up information available for at least 12 months after surgical AF ablation. Twelve-lead electrocardiogram (ECG) and ambulatory Holter monitoring were retrospectively and manually analyzed by two electrophysiologists (K.W.H., J.H.C). Ethical approval was obtained from the Institutional Review Board for conducting this study.