Inclusion Criteria:

• Patients with documented atrial fibrillation for more than 72 hours for whom cardioversion and antiarrhythmic treatment is indicated in the opinion of the investigator and under oral anticoagulation

Exclusion Criteria:

• Contraindication to oral anticoagulation
• Patient having received amiodarone in the past whatever the date (more than a total of twenty 200 mg tablets or more than 5 days intravenous)
• Patients known to have chronic AF, patients with atrial flutter or paroxysmal atrial fibrillation
• Severe congestive heart failure with New-York Heart Association (NYHA) class III or IV, severe bradycardia, high degree atrio-ventricular block, ongoing potentially dangerous symptoms when in AF such as angina pectoris, transient ischemic attacks, stroke, syncope, as judged by the investigator, first degree family history of sudden cardiac death below age 50 years in the absence of coronary heart disease, significant sinus node disease without a permanent pacemaker implanted
• History of torsades de pointes or long QT syndrome or QT- or QTc-interval ≥500 msecs before randomization
• Treatment with other class I or III antiarrhythmic drugs which cannot be discontinued
• Dysthyroidism or other contraindication to amiodarone

The above information are not intended to contain all the considerations relevant to a patient's potential participation in a clinical trial.