Double‐Blind Comparison of Cibenzoline Versus Flecainide in the Prevention of Recurrence of Atrial Tachyarrhythmias in 139 Patients

Background: The efficacy and safety of antiarrhythmic drugs for the prevention of atrial arrythmias are controversial because previous studies were nonrandomized or involved nonselected patients. The aim of this study was to evaluate the efficacy and tolerance of two Class I antiarrythmic drugs, cibenzoline, and flecainide, for the treatment of atrial arrhythmias in carefully selected patients. Patients and Methods: One hundred thirty‐nine patients suffering from documented atrial arrhythmias (mean age 63 ± 12 years, 80 males, 59 females) were enrolled in randomized, double‐blind, parallel clinical trials. Seventy patients received cibenzoline and 69 received flecainide; they were followed for a period of 6 months. All patients had good systolic ventricular function. The recurrence of atrial arrhythmias was diagnosed on symptoms, resting ECG, and 24‐hour ambulatory ECG 3 and 6 months after commencing treatment. Results: Twenty‐seven patients were withdrawn during the study, 13 for adverse side effects, 4 for proarrhythmic effects, and 3 for medical events; 7 were lost to follow‐up. Forty‐three patients had one recurrence of atrial arrhythmias (23 in the cibenzoline group, 20 in the flecainide group). The cumulative percentage of patients free from recurrence was not significantly different in either group at 6 months (63.7% in the cibenzoline group and 66.8% in the flecainide group). Cardiac adverse side effects were more frequent with flecainide than cibenzoline (5 vs. 2). One atrial proarrhythmic effect was observed. Conclusion: Cibenzoline and flecainide are both Class I antiarrhythmic agents which are well tolerated and may be safely administered to prevent alrial arrhythmias. A.N.E. 1999;4(1):53–59