Optimal Timing of Dronedarone Initiation After Conversion in Patients With Persistent Atrial Fibrillation

Primary Objective: - Evaluate the rate of Atrial Fibrillation (AF) recurrences one month after randomization according to different timings of initiation of dronedarone. Secondary Objective: * Evaluate the rate of AF recurrences two months after randomization. * Assess the safety of the change from amiodarone to dronedarone * Assess dronedarone safety * Explore dronedarone and its active metabolite plasma level (in a subset of countries) * Explore potential Pharmacokinetic (PK) interaction between dronedarone and amiodarone (in a subset of countries)