OBJECTIVES: The clinical trial on cardioversion and subsequent sinus rhythm maintenance or pharmacological ventricular rate control in chronic atrial fibrillation patients revealed no significant differences between compared therapeutic strategies. The study was aimed at analyzing the costs of alternative strategies to determine effective allocation of limited resources. METHODS: A cost minimization analysis was implemented because both strategies are associated with similar clinical benefits. The retrospective costs for 205 patients randomly assigned to studied groups were calculated over the time horizon of 12 months. The costs of diagnostic and treatment procedures, hospitalizations, out patients visits, drugs and physicians' consultations were estimated for both groups using data gathered alongside clinical trial. Expected costs, and incremental cost were identified. The sensitivity analysis on unit cost driver items were performed. The results are expressed in USD (PLN were transformed by 2001 PPP value). RESULTS: The conservative strategy with pharmacological ventricular rate control was less costly then cardioversion and subsequent sinus rhythm maintenance, 2850 USD (PPP) and 1350 USD, respectively. The cost driver contributing to observed difference was the cost of cardioversion. Additional cost drivers were the cost of echocardiography, 24 hours ECG recording, cardiologists consultations, hospitalization costs including intensive care and cardiology unit services. The sensitivity analysis performed on the cost drivers confirmed the domination of the conservative strategy. CONCLUSIONS: The cardioversion and subsequent sinus rhythm maintenance in chronic atrial fibrillation patients is more costly then pharmacological ventricular rate control.