[Cibenzoline versus propafenone by the oral route for preventing recurrence of atrial arrhythmia: multicenter, randomized, double-blind study].

This multicentre, randomized, double-blind study, conducted in parallel groups, was designed to compare the efficacy and safety of cibenzoline (C) and oral propafenone (P) in the prevention of recurrent atrial arrhythmias (M) over a 6-month period. Patients of either sex with reduced atrial fibrillation or flutter and predominantly in sinus rhythm (> 50%), with a left ventricular shortening fraction greater than or equal to 20% and not receiving any antiarrhythmic treatment were included. Patients presenting severe conduction disorders, severe heart failure (NYHA class III or IV), marked hypotension or recent myocardial infarction were not included. Treatments were administered at the dosage of one tablet twice a day, i.e. 260 mg/day of cibenzoline or 600 mg/day of propafenone. This dosage was reduced by one half in elderly patients (> 70 years). Patients were seen on inclusion (Dzero), and at the third and sixth months or in the case of recurrence of symptoms. Recurrent arrhythmias were assessed by ECG and 24-hour Holter monitoring and according to the symptoms experienced by the patients. Sixty-five patients, 36 men and 29 women, between the ages of 34 to 86 years and presenting an atrial arrhythmia-atrial fibrillation (80%) or atrial flutter (20%)-were included in the trial: 34 patients received cibenzoline and 31 received propafenone. The arrhythmia had already been treated in 78% of cases. Its aetiology was related to hypertensive heart disease (32%), valvular heart disease (8%), other (17%) or idiopathic (43%). The arrhythmia was symptomatic in 91% of patients on inclusion. The ultrasonographic left ventricular shortening fraction was 32.8 +/- 8.1% in group C and 32.6 +/- 6.4% in group P. The two groups were comparable before treatment. The efficacy of the two treatments was comparable: no significant difference in the number of recurrences was demonstrated: 11 patients treated with C and 12 patients treated with P; cumulative percentages of patients without recurrence with good tolerance of treatment (Kaplan-Meier acturial curves) at 6 months were 55.9% with C and 48.4% with P(NS); probability of no recurrence at 6 months (0.63 +/- 0.09 in group C and 0.57 +/- 0.09 in group P); mean time to recurrence (53.4 +/- 44.3 days in group C and 61.6 +/- 35.3 days in group P). Adverse events leading to discontinuation of treatment occurred in 4 patients from each group, and one proarrhythmic effect at 6 months in a patient in group P. The treatments were well tolerated in the majority of cases: there was no significant difference in the number of patients presenting at least one adverse event: 9(26.5%) in group C, 11(35.5%) in group P. Most events were considered to be mild or moderate. The effects of the two treatments on the course of blood pressure, heart rate, PR interval and QT interval calculated at 3 and 6 months compared to DO were not statistically different. The QRS interval increased to a significantly greater extent in group C that in group P (p = 0.02 at 3 months; p = 0.0005 at 6 months). No significant difference was observed between the two groups for the course of laboratory parameters at 3 and 6 months compared to DO in the patients present at these three visits. Cibenzoline can therefore constitute a good alternative to propafenone in the prevention of symptomatic recurrences of atrial tachyarrhythmias. The preferential use of one or other treatment can be guided by individual factors, including tolerance.