The purpose of the study is to assess the efficacy of flecainide controlled release (CR) in the prevention of recurrent AF during 9 months of active treatment compared to placebo in patients with only one documented AF episode.

Inclusion Criteria:

• History of first symptomatic & documented episode of AF
• LVEF > 40% and not on AAD and in sinus rhythm at time of recruitment

Exclusion Criteria:

• History of more than 1 symptomatic documented AF episode, persistent or permanent AF.
• History of ablation for previous AF
• Reversible cause for AF (e.g.thyroid, alcohol, pulmonary embolism, surgery
• Severe symptoms during AF episode (e.g.syncope, chest pain)
• All types of treated arrhythmias other than AF
• History of myocardial infarction (MI), coronary artery disease (CAD), heart failure (I, II, III and IV of New York Heart Association -NYHA- classification) or valvular diseases
• Left ventricular ejection fraction (LVEF) ≤ 40%
• Bradycardia < 40 beats/min and all ECG abnormalities: PR> 240ms or QRS> 120 ms or QTc> 440 ms
• Brugada syndrome
• Conduction disturbances: complete bundle branch block (LBBB) or (RBBB), bifascicular block
• 2nd or 3rd degree atrioventricular (AV) block
• Sinus node dysfunction
• Severe hypertension with:Systolic blood pressure ≥ 180 mmHg, and / or· Diastolic blood pressure ≥ 100 mmHg
• Left ventricular hypertrophy (LVH) with septal thickness > 14 mm on Echocardiogram
• Implanted pacemaker
• Heart surgery within the last 6 months, or non-stable postoperative condition
• Renal failure: serum creatinine ≥ 150 µmol/l or creatinine clearance ≤ 50 ml/min (Cockroft and Gault formula
• Uncorrected electrolytic abnormalities
• Have used recently in the last 3 months prior to the inclusion any of the following treatments: Oral amiodarone, Treatments that lengthen QT interval (e.g.Sultopride, Drugs causing torsades de pointe (e.g.mizolastine, pentamidine, sparfloxacin, moxifloxacin, Bupropion
• Anti-hypertensive drugs other than permitted in the study: ACE-I, ARB (sartans) and DHP from Calcium channel blockers (CCB