Inclusion rate too low. Recruitment of further study centers too costly.

The purpose of this study is to determine whether Eplerenone reduces atrial fibrillation (AF) recurrences within the first 8 weeks after electrical cardioversion of persistent AF.

Inclusion Criteria:

• Persistent atrial fibrillation (AF), AF persistence for > 7 days but < 1 year
• Total AF history < 2 years
• Written informed consent of the patient
• Age ≥18 years
• Female patients are sterilised or postmenopausal or apply an adequate method for contraception (Pearl index <1%) and have a negative pregnancy test (ß-HCG) and do not breastfeed/nurse.

Exclusion Criteria:

• Hemodynamic instability or symptoms not allowing cardioversion to be delayed for 3 weeks
• Myocardial infarction within the last 3 months
• Heart failure NYHA class III - IV
• Uncontrolled hypertension, defined as a systolic blood pressure > 160 mm Hg and/or a diastolic blood pressure > 95 mm Hg (anti-hypertensive treatment is allowed).
• Pre-treatment with an aldosterone antagonist or other potassium sparing diuretics
• Instable angina pectoris
• Use of Digitalis
• Use of class I or class III antiarrhythmic drugs (must be stopped at least 5 half-life before)
• Contraindication or hypersensitivity to ß-blockers
• Open heart surgery within the last 3 months
• Pregnancy
• Acute and reversible illnesses
• Acute and chronic infection
• Alcohol or drug abuse or a severe progressive extracardiac disease
• Untreated manifest and latent hyper- or hypothyroidism or < 3 months peripheral euthyroidism (normal fT3)
• Moderate to severe renal insufficiency (Creatinine clearance less than 50 ml/min)
• Patients with liver cirrhosis (Child-Pugh class C)
• Co-administration of strong CYP3A4 inhibitors (e.g. Itraconazole, Ketoconazole, Ritonavir, Nelfinavir, Clarithromycin, Telithromycin and Nephazodon)
• Hypersensitivity against Eplerenone and/or one of the other components of the tablet (see Fachinformation)
• Serum potassium > 5 mmol/l
• Patients unlikely to comply with the protocol