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

Abstract

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.