Efficacy and safety of ibutilide fumarate for the conversion of atrial arrhythmias after cardiac surgery

Background-Atrial arrhythmias occur commonly after cardiac surgery and are a cause of significant morbidity and increased hospital costs, yet there is no well-studied treatment strategy to deal with them expeditiously. The pu rpose of this study was to determine the efficacy and safety of ibutilide f umarate, an approved drug for the rapid conversion of atrial fibrillation a nd flutter, in patients after cardiac surgery. Methods and Results-Patients with atrial fibrillation or flutter occurring 1 to 7 days after surgery and lasting 1 hour to 3 days were randomized to r eceive two 10-minute blinded infusions of placebo or 0.25, 0.5, or 1.0 mg o f ibutilide fumarate, Treatment was considered successful if sinus rhythm w as restored for any period of time by hour 1.5. A total of 302 patients wer e randomized, 201 with fibrillation and 101 with flutter, Treatment with ib utilide resulted in significantly higher conversion rates than placebo, and efficacy was dose related (placebo 15%; ibutilide 0.25 mg 40%, 0.5 mg 47%, and 1.0 mg 57%), Conversion rates at all doses were higher for atrial flut ter than for atrial fibrillation, Mean time to conversion decreased as the dose was increased. Polymorphic ventricular tachycardia was the most seriou s adverse effect and occurred in 1.8% of the ibutilide-treated patients com pared with 1.2% of patients who received placebo. Conclusions-Ibutilide is a useful and safe treatment alternative for the at rial arrhythmias that occur after cardiac surgery.