The purpose of this study is to examine the overall effectiveness of short-time anti-arrhythmic drug treatment with amiodarone (to control heart rhythm) to prevent short-and long-term atrial fibrillation following an ablation procedure for atrial fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and it is associated with increased mortality and morbidity due to increased risk of stroke, poor quality of life and risk of developing heart failure.

Today, catheter ablation has become a standard procedure in the treatment of symptomatic atrial fibrillation, but so far there is no official recommendations regarding the use of antiarrythmic drugs after the procedure. Nevertheless, it is common standard practice to prescribe antiarrhythmic drugs for the first 2-3 months after the intervention to prevent early recurrences. To our knowledge, the effect of antiarrythmic drugs following ablation for atrial fibrillation has only been evaluated in a few recent studies. None of these have evaluated the long term effect of short term antiarrythmic drug treatment. In addition, none of the trials have been conducted placebo-controlled.

In this study patients with paroxysmal or persistent atrial fibrillation will be considered for randomisation. Following the ablation procedure, patients will be randomized to receive either amiodarone or placebo for a period of 8 weeks. Clinical visits including a physical exam, 12 lead ECG recording and blood samples, will be scheduled during the follow-up time. Furthermore patients will be evaluated with Quality of Life questionaires and Holter monitoring.

The primary endpoint of the study is freedom from atrial fibrillation, atrial flutter or atrial tachycardia at 6 months follow-up.

Inclusion Criteria:

• Patients with symptomatic paroxysmal or persistent atrial fibrillation undergoing catheter ablation for atrial fibrillation. (persistent episodes may last no more than 12 months)

Exclusion Criteria:

• Contraindication or intolerance to amiodarone.
• Prolonged amiodarone treatment within 3 months before the planned ablation procedure.
• Previous participation in this study.
• Other cardiac arrythmias (patients with co-existing atrial flutter can be included).
• Antiarrhythmic treatment for indication other than atrial fibrillation (or atrial flutter).
• Heart failure (NYHA class III or IV or left ventricular ejection fraction < 35%).
• Significant heart valve disease.
• Significant lung disease, thyroid dysfunction or liver disease.
• Inability or unwillingness to be treated with anticoagulation before and during the study.
• Females with birth giving potential
• Failure to give informed concent.