Antiarrhythmic efficacy of azimilide in patients with atrial fibrillation. Maintenance of sinus rhythm after conversion to sinus rhythm

Background Azimilide dihydrochloride (azimilide) is an investigational antiarrhythmic drug that has been tested in patients with a variety of arrhythmias. In patients with atrial fibrillation, it has shown excellent efficacy in some previous trials and minimal efficacy in others. Methods Patients who had symptomatic atrial fibrillation for >48 hours but <6 months were eligible for this multicenter, randomized, placebo-controlled clinical trial. Patients were admitted to a hospital and randomly assigned to receive either azimilide 125 mg or a matched placebo twice daily for 3 days and then once daily. Patients who were in sinus rhythm spontaneously or had sinus rhythm restored by electric cardioversion on day 4 were discharged from the hospital. Recurrence of atrial fibrillation was documented by electrocardiogram. In the primary efficacy analysis, time to recurrence in the 2 treatment groups was compared with the log-rank test in the subgroup of patients with structural heart disease. Safety was assessed as deaths, adverse events, and serious adverse events. Results A total of 446 patients were randomized in the study; 314 were in the subgroup with structural heart disease. The median time to arrhythmia recurrence in both treatment groups with structural heart disease was 13 days, and the difference between treatments was not significant (P = .4596, n = 314). The relative risk for recurrence (placebo:azimilide) was 1.104 (95% CI 0.849-1.436). There was 1 death in the placebo group and 3 in the azimilide group. Conclusions Azimilide did not demonstrate clinically important or statistically significant efficacy in reducing the risk for arrhythmia recurrence in patients with structural heart disease who were in atrial fibrillation and converted to sinus rhythm.