Fifty-five patients (34 males, 21 females) have been treated for resistant paroxysmal atrial fibrillation (39 cases) or supraventricular tachycardia (16 cases) for 3 to 32 months. Most of these patients were free of heart disease but were severely limited in their daily activities by the arrhythmia. Most were resistant to membrane-stabilizing agents or to amiodarone. Complete suppression of the arrhythmia was achieved in 44 patients (by flecainide alone in 38 patients and by a combination of flecainide and amiodarone in 6 patients). In 6 other cases, a significant reduction in the number of attacks and a concomitant improvement in the quality of life was obtained (by flecainide alone in 2, and by the combination of flecainide and amiodarone in 4). Five patients remained uncontrolled. This experience demonstrates that flecainide is highly effective in refractory atrial tachyarrhythmias. It allows a reduction in the dosage of amiodarone when both drugs are combined.