Comparison of flecainide and procainamide in cardioversion of atrial fibrillation.

In this prospective, controlled and randomized cross-over study we tried to establish the efficiency and safety of flecainide vs procainamide for the treatment of acute atrial fibrillation. Eighty patients (30 females, 50 males, mean age: 55 +/- 14 years) were included. Patients entered into the study if they had atrial fibrillation of recent onset (< 24 h) with a ventricular rate > 100 beats.min-1 at rest and were < 75 years of age. Exclusion criteria were any sign of heart failure, conduction disturbances, sick sinus syndrome or acute ischaemic events. Randomly 40 patients received flecainide and 40 procainamide as the first treatment. There were no significant clinical difference between the two groups. Procainamide ws given at a dose of 1 g infused over 30 min, and followed by an infusion of 2 mg.min-1 over 1 h. Flecainide was given at a dose of 1.5 mg.kg-1 over 15 min followed by an infusion of 1.5 mg.kg-1 over 1 h. Drug infusion was continued until maximal dose, intolerance or reversion to sinus rhythm. After 1 h of wash out, patients remaining in atrial fibrillation were started on the second drug. Left atrial size was measured by echo. Serum levels of drug and atrial size did not differ between patients who returned to sinus rhythm and those who remained in atrial fibrillation. Conversion to sinus rhythm was achieved in 37 (92%) of the 40 patients treated with flecainide and 25 (65%) of those treated with procainamide (P < 0.001). The time required for reversion to sinus rhythm was similar between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)