The authors submit a clinical and electrocardiographic analysis of five patients with atypical ventricular tachycardia with atrioventricular block of an advanced degree. The incidence is relatively rare--cca 1% patients with atrioventricular block are threatened by this type of tachycardia. In these patients there are always reduced serum potassium levels and a longer QT interval, as compared with patients without tachycardia. In two instances there was an association with the use of drugs (Furosemide and Thioridazine) and these patients developed tachycardia even during permanent pacing. Correction of the internal environment and discontinuation of drugs proved therefore decisive, as permanent pacing alone did not always suffice to prevent tachycardia. Without medication atypical ventricular tachycardia develops, in the author's opinion, most probably when bradycardia has persisted for a prolonged period.

Keywords: Aged; Aged, 80 and over; Arrhythmias, Cardiac /complications/; Electrocardiography; Heart Block /complications/; Humans; Long QT Syndrome /complications/; Middle Aged