[Immediate cardioversion of atrial fibrillation and atrial flutter lasting less than 90 days by ibutilide versus...

To compare the efficacy and safety of ibutilide versus propafenone in immediate cardioversion of atrial fibrillation (AF) and atrial flutter (AFL) lasted less than 90 days.

212 consecutive patients suffering from AF or AFL all lasting less than 90 days that were diagnosed and treated in 5 medical centers were randomly assigned into two groups: ibutilide group (n = 107, including 75 AF cases and 32 AFL cases, receiving intravenous injection of ibutilide 1mg over 10 minutes) and propafenone group as control group (n = 105, including 76 AF cases and 29 AFL cases, receiving intravenous injection of propafenone 70 mg over 10 minutes). If AF/AFL still persisted 10 minutes after treatment, the above dose was repeated. The conversion rate within 1.5 hours and adverse effects within 4 hours were observed.

(1) The conversion rate on AFL of the ibutilide group was 78.1%, significantly higher than that of the propafenone group (48.3%, P < 0.01), while no significant difference was observed in the conversion rate on AF (54.7% vs. 39.5%, P > 0.05) and the mean conversion time (P > 0.05). However the overall conversion rate on AFL and AF of the ibutilide group was 61.7%, significantly higher than that of the propafenone group (41.9%, P < 0.05). (2) The conversion rate on AF/AFL lasting less than 48 h was 65.9% in the ibutilide group, not significantly different from that of the propafenone group (55.7%), the conversion rate on AF/AFL lasting 3 approximately 30 d in the ibutilide group was 66.7%, significantly higher than that of the propafenone group (26.3%, P < 0.05), and the conversion rate on AF/AFL lasting 31 - 88 d was 50%, significantly higher than that of the propafenone group (0, P < 0.01). (3) There was no difference in the times needed for conversion between these 2 groups. (4) The most severe adverse effect in the ibutilide group was short run of ventricular tachycardia occurring in 5 cases among which 4 cases recovered simultaneously and one case recovered after accepting a bolus dose of 100 mg lidocaine. The most severe adverse effects in propafenone group were RR interval longer than 1.5 s (4 cases) and transient hypotension. An acute coronary event was also seen in propafenone group, however, unrelated to the experimental drug.

Intravenous administration of ibutilide in cardioversion of AF and AFL is safe and effective.