OBJECTIVETo investigate the efficacy and safety of intravenous ibutilide for conversion of atrial fibrillation (AF) and flutter (AFL) to sinus rhythm.

METHODSNinety-nine consecutive patients aged 18-75 y with AF/AFL were included. The duration of arrhythmia was <90 d (1 h-90 d) and ventricular rate was >60 beats/min. Patients were assigned randomly into two groups: 49 patients in ibutilide group received ibutilide 1 mg, then repeated if AF/AFL was not converted after 10 min; 50 patients in propafenone group received propafenone 70 mg, then repeated if AF/AFL persisted after 10 min. Two drugs were diluted by 50 ml of 5% glucose and injected intravenously within 10 min.

RESULTSVentricular rates were decreased in both groups. AF/AFL were converted in 34 of 49 patients (69.4 % ) in ibutilide group and in 22 of 50 patients (44.0 %) in propafenone group (P <0.05). The converting time of ibutilide was significantly shorter than that of propafenone [(16.79 ± 12.31) min compared with (36.92 ± 11.38)min, P <0.01]. The most serious adverse effect of ibutilide was non-sustained monomorphic ventricular tachycardia (3/49,6.12 %). Transient hypotension and heart pause were the main adverse events in patients who received propafenone, acute left heart failure occurred in one patient of propafenone group.

CONCLUSIONIntravenous ibutilide is a safe and effective agent for cardioversion of recent-onset AF/AFL. Furthermore,strict processing under electrocardio-monitoring is important.