[Electrophysiological evaluation of ventricular tachycardia]

The ability to induce and terminate ventricular tachycardia reproducibly by programmed stimulation has led to the development of electrophysiological investigations for the management of patients suffering from spontaneous arrhythmias. The investigation consists in introducing several multipolar catheter electrodes under local anaesthesia which are then positioned in contact with the endocardium in several regions of the heart. There is no consensus as to an ideal stimulation protocol for these patients but the basic principle is the introduction of one or several ventricular extrasystoles every 8 beats in sinus rhythm or during a controlled ventricular paced rhythm. At present, the major indication is rarely diagnostic in the presence of wide QRS complex tachycardias difficult to analyse by electrocardiography. On the other hand, electrophysiological investigations are highly recommended in cases of unexplained syncope in patients with documented or suspected heart disease, in symptomatic patients with intraventricular conduction defects in whom ventricular arrhythmias are suspected as the cause of symptoms or after cardiac arrest without transmural infarction or, for many teams, after the 48th hour of transmural infarction. Electrophysiological investigations are also justified in patients in whom surgical or catheter ablation of an arrhythmogenic focus is planned because of resistance to antiarrhythmic drug therapy. Evaluation of the efficacy of antiarrhythmic drugs by repeated investigations is common in the United States but is not so widely accepted in Europe.(ABSTRACT TRUNCATED AT 250 WORDS)