Conversion efficacy and safety of repeated doses of ibutilide in patients with atrial flutter and atrial fibrillation. Study Investigators

Abstract

Background: A study was conducted to determine the efficacy and safety of ibutilide fumarate versus placebo in the acute termination of atrial flutter and fibrillation.

Methods and results: Two hundred sixty-two patients aged 28 to 88 years with atrial flutter or fibrillation duration of 3 hours to 90 days were randomly assigned in a 5:1 ratio (ibutilide:placebo) to receive two 10-minute infusions, 10 minutes apart, of ibutilide (1 mg) or placebo. Patients were hospitalized and monitored by telemetry for 24 hours, with follow-up 72 hours later. Seventy-three (34.9%) of 209 evaluable ibutilide recipients had termination of atrial flutter or fibrillation within 1.5 hours compared with 0 (0%) of 41 placebo recipients. Those with atrial flutter had a higher success rate. At hour 24, 86.3% remained in normal or alternative sinus rhythm. Of the patients who received ibutilide, 2.3% experienced drug-related sustained polymorphic or monomorphic ventricular tachycardia and recovered after intervention. Additionally, 7.3% experienced nonsustained polymorphic or monomorphic ventricular tachycardia. Other frequent medical events in ibutilide recipients were generally also noted in the placebo group.

Conclusions: Ibutilide is effective and safe for acute termination of atrial fibrillation or atrial flutter.