Efficacy and safety of ibutilide vs. transoesophageal atrial pacing for the termination of type I atrial flutter.

AIMS: Comparing efficacy and safety of ibutilide vs. transoesophageal atrial pacing (ATP) for the termination of type I atrial flutter (AFL). METHODS AND RESULTS: Eighty-seven patients affected by AFL lasting between 2 h and 30 days were randomized in two groups: Group 1-i.v. ibutilide treatment, up to 2 mg, and Group 2-ATP, with "burst" and "ramp" pacing protocols. Sinus rhythm was restored in 36/45 (80%) patients in Group 1 vs. 18/42 (43%) in Group 2 (P<0.0005). In Group 1, mean AFL duration was 11.4 +/- 7.7 days in responders vs. 12.1 +/- 7.6 in non-responders (P=ns), while in Group 2 it was 2.7 +/- 1.4 vs. 14.2 +/- 5.4 days (responders vs. non-responders, respectively, P<0.0001); 30/36 (83%) responders in Group 1 had AFL >48 h vs. 10/18 (56%) responders in Group 2 (P<0.05). Non-sustained polymorphic ventricular tachycardia occurred in 2 patients in Group 1 vs. none in Group 2 (P=ns). It did not require any specific treatment except the interruption of ibutilide infusion. CONCLUSION: Both ibutilide and ATP proved to be safe and effective for recent onset type I AFL termination, but ibutilide was more effective when the arrhythmia had lasted longer than 48 h.