Objective To assess the efficacy of radiofrequency catheter ablation (RFCA) for idiopathic ventricular tachycardia (IVT) and the location value of electrocardiography for IVT originating.  Methods The electrophysiology characteristics and the efficacy of RFCA in 126 patients with IVT were retrospectively analyzed. Activation mapping was performed in most cases. Radiofrequency energy was maintained at a temperature of 60-65℃.  Results The ventriculoatrial dissociation at IVT episode was found in 117 patients. The successful ablation sites of most patients with IVT were originated from right ventricular outflow tract (62 cases) and left post-septa (43 cases) with other origin (21 cases). The successful rate of catheter ablation was 87.3% in this study

The successful rate of IVT originating from right ventricular outflow tract and left post-septa was significantly higher than that from other sites (96.8% and 90.7% vs 52.4%

P＜0.05). Among 8 patients with syncope existed during IVT episode

4 patients was complicated with atrial-ventricular nodal dual pathways

2 patients had atrial-ventricular pathway

and 2 complicated with multi-morphic ventricular tachycardia. During 6 months to 10 years of follow-up

IVT recurrence was found in 9 cases (8.2%)

but re-ablation was successfully obtained in all patients. 6 patients were complicated with tachycardic myocardiopathy before ablation

but their heart structure and function recovery after 3 months of ablation.  Conclusion RFCA used activation mapping for IVT is an effective and safe method. The surface electrocardiogram at IVT episodes is helpful for IVT originating

but IVT actual sites may be complicated and little IVT may have pathway or atrial-ventricular nodal dual pathways.