[Flecainide controlled-release for prevention of atrial fibrillation relapse]

Flecainide acetate instant release (LI) has been prescribed for years in the prevention of atrial fibrillation (AF) relapse after sinus rate conversion. A new controlled-release (LP) formulation of flecainide was recently introduced. The objectives of this observational study were to evaluate the benefit/risk ratio of LI or LP flecainide treatment for prevention of AF relapse.

EPIFLEC study was an open, prospective, observational study conducted by 151 cardiologists who had prescribed either flecainide LI (group 1) to 838 patients or flecainide LP (group 2) to 214 patients or flecainide LI before LP (group 3) to 242 patients. In these patients, AF was either paroxystic (35%) or persistant (65%). Concomitant pathologies were observed in 80% of these patients (mean age 68 years) with a high incidence (50%) of hypertension. The mean duration of treatment was 6.9 +/- 6.7 months in group 1 (LI), 6.2 +/- 3.1 months in group 2 (LP) and 12.7 +/- 5.4 months in group 3 (LI-LP).

mean daily dosages of flecainide were similar among the 3 groups. Antithrombotic drugs were prescribed in 74% (group 1) to 83% (group 2) of the patients and another antiarrhythmic drug was associated to flecainide among 12 to 21% of the patients. AF relapse was observed in 171 patients in group 1 (LI), 38 patients in group 2 (LP) and 39 patients in group 3 (LI-LP). The incidence of AF relapse was compared in groups 1 and 2 at 10 months of follow-up and AF relapse probability was not significantly different between flecainide LI and LP :26 +/- 2% and 23 +/- 4% respectively (OR = 0.99, CI 95%:0.69-1.4; p = 0.96). A multivariate analysis showed that previous multiples episodes of AF, electrical shock rate conversion and history of flutter and hypertension were independent predictors of AF relapse. Among 11 deaths observed during follow-up, only 2 were cardiovascular. The most frequent non lethal cardiovascular adverse events were arrhythmias or cardiac conduction disorders and were limited to less than 5% of the patients. Only 5 supraventricular transient pro arrhythmias episodes were recorded.

this pharmaco-epidemiological study in private practice confirms that flecainide is able to prevent AF relapse in 75% of patients at 10 months and that the tolerance of the treatment is acceptable in these patients.