GISSI-AF - Use of Valsartan an Angiotensin II AT1-Receptor Blocker in the Prevention of Atrial Fibrillation Recurrence

Inclusion Criteria: 1. Male or female patients \>=40 years of age 2. Sinus rhythm 3. At least two ECG documented episodes of symptomatic AF in the previous 6 months or After a successful cardioversion for AF performed between 14 days and 48 hours before randomization 4. At least one of the following underlying cardiovascular diseases/comorbidities: * heart failure/documented history of LV dysfunction (defined as an EF \<40%) * history of hypertension \>=6 months with/without LVH * Type II diabetes mellitus * documented history of stroke or peripheral vascular disease * documented history of coronary artery disease * lone atrial fibrillation with documented LA dilation (LA diameter \>=45 mm for men and \>=40 mm for women) 5. Written informed consent to participate in the study prior to any study procedures Exclusion Criteria: 1. Need for a continuous treatment with ARBs for any clinical reasons 2. Contraindications or known hypersensitivity to ARBs 3. Persistent standing systolic blood pressure \< 110 mmHg 4. Recent (\<6 weeks) acute myocardial infarction or bypass surgery, or percutaneous coronary intervention 5. Clinically significant valvular etiologies 6. Thyroid dysfunction 7. Indication for pacemaker or ICD implant or for an ablative treatment, recent (\<6 months) PM or ICD implant, previous ablative treatment 8. Planned cardiac surgery, expected to be performed within 3 months 9. Serum creatinine level above 2.5 mg/dL 10. Significant liver disease 11. Pregnant or lactating women or women of childbearing potential who are not protected from pregnancy by an accepted method of contraception 12. Any condition that in the opinion of the investigator would jeopardize the evaluation of efficacy or safety or be associated with poor adherence to the protocol 13. Presence of any non-cardiac disease (e.g. cancer) that is likely to significantly shorten life expectancy 14. Treatment with any investigational agent within 1 month before randomization 15. Currently decompensated heart failure