Pharmacokinetics and Optimal Timing of Dronedarone Initiation Following Long-term Amiodarone in Patients With Paroxysmal or Persistent Atrial Fibrillation

Inclusion criteria: Screening: * Paroxysmal or persistent AF having received at least 6 months of amiodarone before screening with at least the last 2 months at a regimen of 200 mg/day (during at least 5 days per week) prior to screening * Requiring a change from amiodarone treatment whatever the reason, but without liver, lung or thyroid toxicity related to previous use of amiodarone * At least one cardiovascular risk factor (i.e. age \> 70, hypertension, diabetes, prior cerebrovascular disease or left atrial diameter \>= 50 mm * Effective anticoagulation treatments verified by International Normalized Ratio (INR) (target INR \> 2) * QTc Bazett \< 500 ms on 12-lead ECG Randomization: * Outpatients and Inpatients (except patients hospitalized during screening period for SAE) * Sinus rhythm * Effective oral anticoagulation treatment verified by INR (target INR \> 2). INR should be closely monitored after initiating dronedarone in patients taking vitamin K antagonist as per their label * QTc Bazett \< 500 ms and PR \< 280 ms on 12-lead ECG Exclusion criteria: Screening: * Contraindication to oral anticoagulation * Acute condition known to cause AF * Permanent AF * Bradycardia \< 50 bpm at rest on the 12-lead ECG * History of, or current heart failure or left ventricular systolic dysfunction * Unstable hemodynamic conditions * Severe hepatic impairment * Wolff-Parkinson-White Syndrome * Previous catheter ablation for atrial fibrillation or catheter ablation scheduled in t…