Flec-SL: short- vs. long-term flecainide after AF cardioversion

The goal of antiarrhythmic therapy following cardioversion for atrial fibrillation (AF) is to prevent further recurrences for as long as possible.  However, it is known that the atrial action potential normalises after 2-4 weeks of sinus rhythm, suggesting that drugs may not be essential in the long-term.  The goal of this study was to investigate whether short-term antiarrhythmic treatment following cardioversion for AF was non-inferior to long-term treatment.

In this prospective, randomised trial, patients at 44 centres in Germany were randomly assigned to either no antiarrhythmic treatment, treatment with 200-300mg of flecainide per day for 4 weeks, or flecainide treatment for six months.   The primary endpoint measure was the time to persistent atrial fibrillation or death, the former being assessed in a core laboratory who were masked as to the patient’s treatment group.

Overall the primary outcome occurred in 46% of patients receiving short-term treatment versus 39% of patients receiving long-term treatment; the difference between the two groups in the mean percentage of patients who did not have persistent AF was 7.9%, which did not reach the specified non-inferiority margin (p=0.2081).  A post-hoc analysis of all patients who had not reached the primary endpoint in the first month found long-term treatment to be superior to short-term treatment (p=0.0001).


Although antiarrhythmic short-term treatment with flecainide after cardioversion for AF was not non-inferior to long-term treatment, this study shows that short-term treatment can be considered for AF patients who are at increased risk for adverse drug effects or other complications.

  • Kirchhof P, Andresen D, Bosch R et al.  Short-term versus long-term antiarrhythmic drug treatment after cardioversion of atrial fibrillation (Flec-SL): a prospective, randomised, open-label, blinded endpoint assessment trial.  Lancet 2012; doi:10.1016/S0140-6736(12)60570-4.

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