RESUMO
AIM: The aim of our study was to compare the efficacy and safety of ibutilide and amiodarone (intravenously) in converting recent-onset atrial fibrillation (AF) and atrial flutter (Af) to sinus rhythm (SR). METHODS: The study was prospective, randomized and included 152 (103 men and 49 women) consecutive patients with AF or Af of 3-48 h duration. Ibutilide is a selective class III antiarrhythmic agent which when administered intravenously can terminate AF and Af. Amiodarone is also a class III antiarrhythmic agent that when given intravenously or orally has proved to be more effective than other agents in terminating AF and Af [B.N. Singh, F.V. Mody, B. Lopez, J.S. Sarma. Antiarrhythmic agents for atrial fibrillation: focus on prolonging atrial repolarization. Am J Cardiol 1999 Nov 4; 84: 161R-173R.]. Seventy-nine patients (56 with AF and 23 with Af) that consisted group A were treated with ibutilide. Seventy-three (52 with AF and 21 with Af) consisted group B and were treated with intravenous infusion of amiodarone. RESULTS: The conversion rate of group A (ibutilide) was significantly higher than the conversion rate of group B (amiodarone) (80% vs. 57%, p=0.0054). As regards the kind of arrhythmia separately, for AF there wasn't significant difference (77% vs. 69%, p=ns) whereas for Af ibutilide was superior to amiodarone (87% vs. 29%, p=0.003). The conversion rates of ibutilide didn't differ for AF and Af (77% vs. 87%, p=ns). CONCLUSIONS: Ibutilide is more effective than amiodarone in converting recent-onset Af to SR whereas both drugs are equally effective in converting recent-onset AF to SR.