40 patients (28 males and 12 females) aged (65±12) years with atrial fibrillation (AF), were studied the effect of amiodarone on clinical signs of atrial fibrillation depending on the duration of the QTc interval. In patients with atrial fibrillation amiodarone therapy is more effective when QTc is initially normal, and less efficient when QTc interval is initially prolonged. Tendency to further increase of the initially prolonged QTc requires high quality control in amiodarone therapy of these patients.
