Incidence and risk factors for development of atrial fibrillation after cardiac surgery under cardiopulmonary bypass

BACKGROUND AND AIMS: Atrial fibrillation (AF) is a common postoperative complication after cardiac surgery due to multifactorial causes. The aim of this study was to evaluate the incidence and risk factors of postoperative atrial fibrillation (POAF) after cardiac surgery under cardiopulmonary bypass (CPB). METHODS: A total of 150 adult patients undergoing coronary artery bypass graft (CABG) surgery and valvular surgeries were included. They were evaluated with respect to preoperative risk factors [age, use of β-blockers, left ventricular ejection fraction (LVEF), previous myocardial infarction (MI) and diabetes], intraoperative factors (CABG or valvular surgery, duration of CPB and aortic cross clamp time) and postoperative factors (duration of inotropic support and ventilatory support). Outcome measure was POAF after cardiac surgery under CPB. Postoperative intensive care unit and hospital stay and mortality were also studied. RESULTS: Of the patients who developed POAF, 50% were less than 60 years, 50.6% were diabetics, 50.7% had prior MI,19.7% had LVEF <40%, 82.6%were not on β-blockers, 66.7% had aortic cross clamp time >60 min and 60% had surgery with CPB time >100 min. About 38.8% underwent CABG and 43.1%underwent valvular surgery. There was a positive association with LVEF <40%, prior MI, post-bypass inotropic support greater than 10 min and ventilatory support more than 24 h with the development of POAF. CONCLUSION: The incidence of POAF after cardiac surgery was 40.7%. Preoperative LVEF <0.4, prior MI, CPB time >100 minand extended ventilation for >24 h were significantly associated with POAF.