title: Idiopathic paroxysmal ventricular tachycardia with a QRS pattern of right bundle branch block and left axis deviation: a unique clinical entity with specific properties.
abstract: Electrophysiologic evaluation before and after the serial administration of verapamil, lidocaine, propranolol, and procainamide was undertaken in 4 young, asymptomatic patients with recurrent, sustained ventricular tachycardia (VT). No patient had obvious organic heart disease. The electrocardiogram during sinus rhythm showed S-T depression and T-wave inversion over the inferior and lateral precordial leads in 3 patients. QRS morphologic characteristics during episodes of VT showed a pattern of right bundle branch block and left axis deviation. In all 4 patients, VT could be both induced and terminated with electrical stimulation. Verapamil terminated VT and prevented the induction of sustained VT in 3 patients, and markedly slowed the rate of VT in 1 patient. Procainamide effectively prevented the induction of sustained VT in 2 patients, and although ineffective in preventing induction in 2 patients, it slowed the rate of tachycardia in both. Lidocaine and propranolol did not prevent the induction of VT in any patient. These findings suggest that slow-response tissues may be involved in the genesis of VT in these patients, and that VT in these patients may represent a unique clinical entity with distinct electrocardiographic, electrophysiologic, and electropharmacologic properties.
mesh_terms: D000328:Adult; D002037:Bundle-Branch Block / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008012:Lidocaine / Q000627:therapeutic use; D008297:Male; D011433:Propranolol / Q000627:therapeutic use; D013610:Tachycardia / Q000188:drug therapy; D013614:Tachycardia, Paroxysmal / Q000503:physiopathology*; D014700:Verapamil / Q000627:therapeutic use
chemical_list: D008012:Lidocaine; D011433:Propranolol; D014700:Verapamil