Efficacy of ibutilide for termination of atrial fibrillation/flutter

Objective To investigate the efficacy,safety and tolerance of intravenous ibutilide for conversion of atrial fibrillation(AF)and flutter(AFL)to normal sinus rhythm.Methods Thirty-one consecutive patients aged 18~80 years with AF/AFL were included.The duration of arrhythmia was less than 90 days(ranged from 3 hours to 90 days),and ventricular rate(VR)was more than 60 beats/min.Two groups were assigned randomly.One was the ibutilide group(16 patients);the other was the propafenone group(15 patients).Patients in the ibutilide group received ibutilide 1 mg if body weight≥60 kg or 0.01 mg/kg if body weight60 kg;treatment was repeated if atrial fibrillation or flutter was not converted after 10 min of the first dosage.Patients in the propafenone group received propafenone 70 mg,followed by propafenone 35 mg if atrial fibrillation or flutter persisted after 10 min of the first dosage.Two drugs were diluted by 50 ml of 5% glucose and injected intravenously within 10 mins.Results Both two drugs decreased ventricular rate,but there was not significant difference at group comparison.AF/AFL were converted in 10 of 16 patients(62.5%)in ibutilide group and in 4 of 15 patients(26.7%)in propafenone group(P0.05).Ibutilide had a significantly fast converting time than propafenone[12.70±10.27)min vs(39.75±10.08)min,(P0.01)].Two of 6 patients who were unsuccessful in propafenone group were converted with ibutilide alternatively,but none of the four patients who were unsuccessful in ibutilide group were converted with propafenone alternatively.The side effects were notavoided. Torsade de pointes occurred in one patient with left ventricular dysfunction in ibutilide group;and one patient appeared dizziness and cheiro-numbness,another patient appeared left-sided heart failure in propafenone group.Conclusion This observation suggests the superior efficacy and fast converting time of ibutilide over propafenone when administered to convert AF/AFL to sinus rhythm.Furthermore,it shows that strict processing under electrocardio-monitoring is very important.