Trial to Investigate the Efficacy of Olmesartan in Paroxysmal Atrial Fibrillation

Inclusion Criteria: * Documented paroxysmal atrial fibrillation: ECG documentation of atrial fibrillation at least in one ECG recorded during the last 2 months prior to randomization plus additional ECG recording of sinus rhythm at least 12 hours after the above mentioned ECG documentation. * Age ≥ 18 * Patient informed orally and in writing * Written informed consent of the patient Exclusion Criteria: * Strong clinical evidence for therapy with AT II/ACE inhibitors * AT II/ACE inhibitor therapy within the last month * Therapy with antiarrhythmic agents of class I or class III within the last month, therapy with amiodarone within the last 3 months * Direct current (DC) cardioversion within the last 3 months * Symptomatic bradycardia * Implanted pacemaker or implanted cardioverter/defibrillator with any antitachycardiac algorithm in use * Cardiac surgery or cardiac catheter ablation within the last 3 months * Typical angina pectoris symptoms at rest or during exercise * Known coronary artery disease with indication for intervention * Valvular disease \> II degree * Left ventricular ejection fraction \< 40% * Diastolic blood pressure \> 110mm Hg at rest * Symptomatic arterial hypotension * Known renal artery stenosis * Serum creatinine \> 1.8 mval/l * Relevant hepatic or pulmonary disorders * Hyperthyroidism manifested clinically and in laboratory * Known drug intolerance for AT II inhibitors * Females who are pregnant or breast feeding * Females of childbearing potential who are not using a scientifically accepted method of contraception * Participation in a clinical trial within the last 30 days * Drug addiction or chronic alcohol abuse * Legal incapacity, or other circumstances which would prevent the patient from understanding the aim, nature or extent of the clinical study * Evidence of an uncooperative attitude