Case report: One 21-year-old girl with palpitation and near-syncope received electrophysiology study (EPS). Electrocardiography showed bi-directional ventricular premature complexes (PVCs). (figure 1) Echocardiography showed normal heart structure and function. Holter scan revealed daily PVC amount of 5836 and 77 episodes of non-sustained ventricular tachycardia (VT). Catecholaminergic VT was impressed. Programmed stimulation with extrastimuli under isoproterenol infusion induced non-sustained VT. Left ventricular (LV) voltage map showed no low voltage zone(LVZ). The earliest activation site located at the posteoseptal mitral annulus base with compatible pace map. Radiofrequency ablation (RFA) was done. Bi-directional PVCs recurred 9 months later and second time EPS was performed. Small-sized LVZ was found at anterior subannular area and we ablated the earliest activation site of bi-directional VT (VT1) at LV bottom. Two different types of monomorphic VT emerged after ablation under isoproterenol infusion with RBBB morphology, slightly negative polarity of V5-6, superior axis (VT2) and inferior axis (VT3) respectively. Local electrograms at antero-lateral side of LV showed highly fluctuated prepotentials. The earliest activation site of VT2 was at basal part of antero-lateral LV with compatible pace map, while the earliest activation location of VT3 was at postero-medial LV. (figure 2) RFA was performed. After ablation, no VPCs or VT was inducible.