Comparison of intravenously administered dofetilide versus amiodarone in the acute termination of atrial fibrillation and flutter - A multicentre, randomized, double-blind, placebo-controlled study

Aims This study compared the efficacy and safety intravenous dofetilide wit h amiodarone and placebo converting atrial fibrillation or flutter to sinus rhythm. Methods and Results One hundred and fifty patients with atrial fibrillation or flutter (duration range 2 h-6 months) were given 15-min intravenous inf usions of 8 mu g . kg(-1) of dofetilide (n=48), 5 mg . kg(-1) of amiodarone (n=50), or placebo (n=52 and monitored continuously for 3 h. Sinus rhythm was restored in 35%, 4%, and 4% of patients, respectively (P<0.001, dofetil ide vs placebo; P=ns, amiodarone versus placebo). Dofetilide was more effec tive in atrial flutter than in atrial fibrillation (cardioversion rates 75% and 22%, respectively; P=0.004). The mean time to conversion with dofetili de was 55 +/- 15 min. Dofetilide prolonged the QTc interval (+16% at 20 min ). Amiodarone substantially decreased the ventricular rate in non-converter s (-18 beats . min(-1) at 30 min). Two patients given dofetilide (4%) had n on-sustained ventricular tachycardias, and four (8%) had torsade de pointes , in one case requiring electrical cardioversion. Conclusion Intravenous dofetilide is significantly more effective than amio darone or placebo in restoring sinus rhythm in patients with atrial fibrill ation or flutter. However, when infused intravenously at this dose and rate , dofetilide causes a significant incidence of torsade de pointes. (Eur Hea rt J 2000; 21: 1265-1273) (C) 2000 The European Society of Cardiology.