Amiodarone for Atrial Fibrillation Cardioversion in Cardiac Surgery and Development of a Risk Prediction Model for Recurrence

BackgroundThe optimal timing and efficacy of pharmacological rhythm control in patients with preoperative atrial fibrillation (AF) undergoing cardiopulmonary bypass (CPB) surgery remain unclear. We aimed to evaluate the effectiveness of intravenous amiodarone administration during rewarming on early cardioversion and short-term outcomes, and to develop a predictive model for postoperative AF recurrence. MethodsThis retrospective cohort study included adult patients with preoperative atrial fibrillation who underwent cardiac surgery with CPB. Patients receiving a 150 mg intravenous bolus of amiodarone via the oxygenator at systemic rewarming initiation (nasopharyngeal temperature [&ge;]32{degrees}C) during aortic cross-clamping (ACC) were defined as the amiodarone group (A group, n=423), and were compared with the non-intervention group (NI group, n=191). The primary outcome was sustained sinus rhythm within 12 hours post-cardioversion. Secondary outcomes included myocardial injury (measured by cardiac troponin I, cTnI), inflammatory response (neutrophil count, NEUT), renal function (blood urea nitrogen, BUN), use of inotropic support (milrinone, MIL) and renal replacement therapy (hemodialysis, HD), length of hospital stay (LOHS), and other short-term clinical endpoints. Inverse probability of treatment weighting (IPTW) was used to adjust for baseline imbalances. A multivariable logistic regression model was developed and validated to predict early AF recurrence. ResultsOf 614 patients, 423 were in the A group and 191 in the NI group. After IPTW adjustment, the A group had a significantly higher rate of sustained sinus rhythm (52.5% vs. 7.8%, P<0.001). They also exhibited lower levels of cTnI, NEUT, and BUN, reduced use of MIL and HD, and shorter LOHS, along with other favorable outcomes. NT-proBNP was transiently higher in the A group. The final prediction model--incorporating age, left atrial anteroposterior diameter (LAAD), left ventricular end-diastolic diameter (LVED), right ventricular anteroposterior diameter (RVAD), serum calcium, and comorbidity grade--showed strong discrimination (AUC: 0.866 in the training cohort, 0.795 in the validation cohort). ConclusionAmiodarone administration during rewarming improves early rhythm stability and short-term clinical outcomes in patients with preoperative AF undergoing CPB surgery. A validated risk prediction model identifies patients at high risk for recurrence, supporting individualized perioperative management strategies.