Amiodarone Prophylaxis against postoperative atrial fibrillation in off-pump coronary artery bypass

Background: Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery, with incidence increasing based on surgical complexity. While the CHA₂DS₂-VASc score has been validated to predict POAF risk, standardized prophylactic strategies remain unclear. This study evaluates the safety and efficacy of a low-dose oral amiodarone protocol for POAF prevention in high-risk patients undergoing isolated OPCAB procedures. Objective: To evaluate the impact of low-dose amiodarone prophylaxis against POAF in high-risk patients undergoing OPCAB procedures. Methods: This IRB-approved prospective study included all adult inpatients undergoing isolated OPCAB procedures at a single tertiary care facility between June 2018-June 2021 identified as high risk for POAF (preoperative CHA₂DS₂VASc score > 2). Patients treated with amiodarone prophylaxis were compared to a retrospective historical control group which underwent similar OPCAB procedures in the same center prior to the implementation of amiodarone prophylaxis. Preoperative hospitalized inpatients received a weight-adjusted dose of oral amiodarone on each preoperative day until the day prior to surgery. Patients who were inadequately loaded (<1 g) received 150 mg of amiodarone intravenously in the operating room. Patients with intraoperative symptomatic bradycardia received temporary prophylactic epicardial pacing wires. Postoperatively, all patients received an amiodarone regimen of 200 mg orally twice daily, continued for 15 doses or until discharge. Multivariate logistic models were used to determine the effect of low-dose oral amiodarone prophylaxis on new-onset POAF. Results: A 10.7 % reduction in incidence of POAF requiring treatment was noted in the study group (OR=0.4; 95 % CI [0.167–0.958], p = 0.04), as well as a 12 % decrease in patients requiring AF treatment at discharge (p = 0.017), and significantly reduced time to extubation. All baseline characteristics and safety parameters were similar between groups. Conclusions: The use of a low-dose amiodarone prophylaxis regimen led to significant reduction in new POAF, without apparent adverse effects. This regimen may be considered safe, effective, and feasible for implementation in high-risk OPCAB patients. Further studies in on-pump CABG and valvular patients are needed.