Clinical Electrophysiologic Study Of Idiopathic Ventricular Tachycardia

Idiopathic ventricular tachycardia ( IVT) has different clinical characteristics from ventricular tachycardia (VT) in patients with structural heart disease. IVT itself is not a homogeneous entity, but a nonspecific term, including many subsets. There are controversies about mechanisms of IVT. Radiofrequency catheter ablation(RFCA) has become an effective and relatively safe method for treatment of IVT. However, mapping methods for RFCA remain to be improved. The purpose of this study is to improve recognition of clinical characteristics of IVT, to investigate its electrophysiologic mechanisms, to evaluate various mapping methods for RFCA, and to increase the success rate of RFCA.Materials and methods: Electrophysiologic studies and RFCA were performed in 27 patients ( 16male and 11 female, mean age 35 ± 15 years)with IVT. The patients had a history of recurrent palpitation of 7±11 years. The VT cycle length was 333 ± 70ms. Tachycardia had a right bundle branch block(RBBB) configuration in 16patients, and a left branch block (LBBB) configuration in 11 patients, respectively. All patients had no structural heart diseases, and received 24 hour Holter mornitoring, signal- averaged ECG, and intravenous isoproterenol for induction test of ventricular tachyarrhythmia. Termination tests of ventricular tachyarrhythmia by intravenous adenosine(80~200 μg/Kg) and verapamil (2.5mg ~ 20mg) were performed during spontaneous or induced sustained VT...