Chronic recurrent ventricular tachycardia--an electrophysiological study.

Electrophysiological techniques were used to study 17 patients with chronic recurrent ventricular tachycardia. Twelve of the patients had coronary disease, while eight had pre-existing intraventricular conduction defects. The site of origin of the tachycardia as deduced by analysis of the QRS morphology correlated well with the electrocardiographic evidence of the site of the old infarction. Ventricular tachycardia was induced by pacing techniques in eight patients while it occurred spontaneously during the study in two others. In only four of the eight patients in whom tachycardia was induced, could the arrhythmia be reinduced; the arrhythmia could not be reproduced in one, while reproducibility was not assessed in the remaining three. Tachycardia was terminated by pacing techniques in six patients and by DC cardioversion in four. Ventricular tachycardia was initiated with a run of "torsade de pointes" in four patients. Ventricular tachycardias with varying morphology were observed in three patients. Electrophysiological study was of significant benefit in patient management in 14 of the 17 patients, particularly those with pre-existing intraventricular conduction defects, undocumented tachycardia or undocumented syncope.