Aims Pharmacological conversion to sinus rhythm is generally difficult to achieve, particularly in long-lasting persistent atrial fibrillation (AF). The purpose of this study is to compare the effectiveness of two agents, amiodarone and bepridil, in achieving conversion to sinus rhythm in patients with persistent AF.

Methods and results Amiodarone (A) or bepridil (B) was administered to 40 consecutive patients (36 male subjects, age 61 years) with persistent AF in a prospective, randomised, open label fashion. The pharmacological effects in bringing about conversion to sinus rhythm and subsequently maintaining sinus rhythm were evaluated. If sinus rhythm was not restored within 3 months, direct current (DC) cardioversion was performed. The incidence of adverse effects was also evaluated. Sinus rhythm was restored in seven (35%) of 20 patients in group A (average follow-up of 3.2 months) and in 17 (85%) of 20 in group B (average follow-up of 2.3 months) (p<0.05). After pharmacological or DC cardioversion, sinus rhythm could be maintained in 10 (50%) of 20 patients in group A (average follow-up of 14.7 months) and 15 (75%) of 20 patients in group B (average follow-up of 15.6 months). QT interval and QTc were significantly prolonged compare with the baseline values in group B, but no torsade de pointes was recognised in any of the patients. One patient in the group B developed interstitial pneumonia, but steroid therapy cured the condition.

Conclusions Bepridil was superior to amiodarone in achieving sinus conversion and in maintaining sinus rhythm after cardioversion in patients with persistent AF. Even so, we must be watchful for potentially serious adverse complications when administering bepridil.