ELECTROPHARMACOLOGIC - CHARACTERISTICS AND RADIOFREQUENCY CATHETER ABLATION OF SUSTAINED VENTRICULAR-TACHYCARDIA IN PATIENTS WITHOUT STRUCTURAL HEART-DISEASE

Twenty-six patients (mean age 39 +/- 17 years) with idiopathic sustain ed ventricular tachycardia (VT) were included for study. The patients were divided into two groups: group I: 14 patients with VT originating from the right ventricular outflow tract (wide QRS tachycardia with c omplete left bundle branch block pattern), and group II: 12 patients w ith VT originating from the left ventricle (wide QRS tachycardia with complete right bundle branch block pattern). Most of the group I patie nts (11/14) needed isoproterenol to facilitate induction of VT, and we re sensitive to both verapamil and adenosine. Eight patients had succe ssful radiofrequency (RF) ablation and were free of VT without any ant iarrhythmic drugs. In group II, sustained VT was induced by programmed ventricular stimulation in all the patients (only 3 patients needed i soproterenol for facilitation); verapamil could terminate all the VT b ut none of the patients responded to adenosine. Eight patients receive d RF ablation and 6 patients had successful ablation without recurrent tachycardia on a long-term basis. Different sensitivity to adenosine and isoproterenol between right and left ventricular idiopathic VT sug gested different underlying mechanisms for both types of VT. The patie nts who did not receive catheter ablation still had attacks of VT desp ite antiarrhythmic drug treatment; however, none of these patients had sudden death since the first attack of VT (mean 95 +/- 51 months), su ggesting a benign prognosis in idiopathic VT.