Atrial fibrillation: Three months of antiarrhythmic treatment keep sinus rhythm for 2 years after cardioversion

Introduction: Most relapse to atrial fibrillation (AF) occurs with the first 3 months after cardioversion. No study in a clinical relevant setting has until now been designed to demonstrate if intensive pharmacological treatment during this period affects the long-term prognosis. Hypothesis: Short term treatment after cardioversion is sufficient to keep sinus rhythm in an unselected AF-population. Methods: All patients referred for cardioversion at the Department of Cardiology, University Hospital, Malmö, Sweden, were treated based on time-guided randomisation domisation with amiodarone for 1 month prior to DC-cardioversion and continuing for 3 months, followed by metoprolol (TR1). In case of amiodarone contraindications the treatment was metoprolol or digoxin for the whole period (2 years of follow-up). The alternative randomised treatment modality was metoprolol (TR2) only, or digoxin in case of contraindications. Results: A total of 688 pats were included, 484 in TR1 and 181 in TR2. No demographic differences were found between the groups. 54% of patients in TR1 received amiodarone, and 79% in TR2 received metoprolol. After 2 years 65% in TR1-group were still in SR compared to 37% in the TR2-group. In a multivariate Cox analysis the only clinical relevant risk factors for relapse were (1) Treatment modality and (2) Duration of AF. The hazard ratio (risk for relapse) for TR1 versus TR2 was 0,5 (P=0,0003) and for duration of AF 1,004 per month with AF prior to cardioversion (P=0,003). Conclusion: In order to preserve SR a treatment concept including amiodarone for 1 month prior and 3 months after DC-cardioversion followed by a selective beta-blocker (metoprolol SR) seems to be an effective choice. No risk factor could be identified to define a subgroup of patients who could be excluded from this treatment.