Short-term versus long-term antiarrhythmic drug treatment after cardioversion of atrial fibrillation (Flec-SL): a prospective, randomised, open-label, blinded endpoint assessment trial.

Antiarrhythmic drugs prolong the atrial action potential and refractory period, and thereby prevent recurrent atrial fibrillation after cardioversion. The atrial action potential normalises after 2-4 weeks of sinus rhythm, suggesting that antiarrhythmic drugs might not be needed beyond that period. Therefore, we investigated whether short-term antiarrhythmic drug treatment after cardioversion is non-inferior to long-term treatment.