Comparison of Amiodarone Loading Dosage in the Treatment of Postoperative Atrial Fibrillation: High Versus Standard Dose Treatment

Background: Postoperative atrial fibrillation (POAF) is associated with poor outcomes, including hemodynamic instability, stroke, myocardial infarction, and death. In hemodynamic stable patients, the rhythm-control strategy is more advantageous than rate control. Current standard intravenous amiodarone administration has limited success and a delayed effect; the acute success rate is 44% (8-12 h to several days). Purpose: The aim of this study was to evaluate the effectiveness of higher amiodarone loading dosage to restore sinus rhythm in patients with POAF after noncardiac surgery. Methods: This is a prospective, randomized, controlled single-center study. The study included 39 patients with POAF, divided into group I (n=27) (intravenous 600 mg amiodarone loading dosage over 2 h and infusion of 50 mg/h over a 24-h period) and group II (n=12) (standard protocol; 300 mg of bolus intravenously in 30 min and infusion of 50 mg/h over a 24-h period). The primary endpoint of the study was a restoration of sinus rhythm at the 24th hour. Results: Baseline clinical, laboratory and echocardiographic characteristics of both groups were similar. The patients with higher loading amiodarone dosage had earlier restoration of sinus rhythm (2.38±1.41 vs 8.66±2.87 h, respectively; p=0.015). There was no significant difference in achieving sinus rhythm at the 24th hour between both groups. Conclusion: Higher loading amiodarone dosage increased early conversions to sinus rhythm compared with standard amiodarone protocol in patients with POAF.