In recent years attempts intensified to identify and treat patients with an increased risk of sudden cardiac death caused by malignant ventricular arrhythmias. An elevated dispersion value of the QT interval of surface ECG suggests non-homogeneous repolarization and thus the presence of an arrhythmogenic substrate. In patients with ischaemic heart disease and confirmed malignant arrhythmias after onset of antiarrhythmic therapy changes in the dispersion of the QT interval occur, depending on the antiarrhythmic agent used and the effectiveness of treatment. In the authors group of 40 patients the value of dispersion of the QT interval declined significantly after introduction of effective antiarrhythmic treatment in patients treated with amiodarone and beta-blocker. It may thus be stated that the value of the QT interval dispersion of surface ECG can be used not only as a non-invasive "marker" of sudden cardiac death but also as an auxiliary indicator of effectiveness of antiarrhythmic therapy.

Keywords: Adrenergic beta-Antagonists /therapeutic use/; Aged; Aged, 80 and over; Amiodarone /therapeutic use/; Anti-Arrhythmia Agents /therapeutic use/; Electrocardiography; Female; Humans; Male; Sotalol /therapeutic use/; Tachycardia, Ventricular /drug therapy/; Ventricular Fibrillation /drug therapy/