Backgrounds: Myocardial performance index (Tei index) of left ventricle (LV) could combine features of both systolic and diastolic function of LV. But there has been debates about its reliability and usefulness in right ventricle (RV), which are partly due to inability of simultaneous measurement of RV inflow and outflow unlike LV. Dual pulsed-wave Doppler (DPD) tracing method is a new technique, which makes it possible to obtain flow velocities at individual 2 sampling sites simultaneously. In this study, we evaluated feasibility and reproducibility of RV Tei index using the DPD method (TeiD). Methods: A total of 32 patients who had atrial septal defect (n=16), patent ductus arteriosus (n=9) or pulmonary hypertension (n=7) with or without RV outflow obstruction were evaluated via RV catheterization and echocardiographic evaluation including 2D, tissue Doppler image (TDI) and DPD study. Symptom-limited exercise treadmill test with expired gas analysis was performed and peak exercise capacity was measured. Results: Mean age of study patients was 36짹14 years. RV Tei index by conventional Doppler method (TeiC, 0.25짹0.12) was similar to RV TeiD (0.25짹0.08, p=NS) whereas Tei index by TDI (TeiT, 0.41짹0.08) was significantly larger than TeiD (p<0.001). There was an excellent relationship between RV TeiD and TeiC (r=0.79, p<0.001) but no relationship between TeiD and TeiT (r=0.31, p=NS). TeiD and TeiC showed a moderate degree of inverse correlation with peak early diastolic tricuspid annular (E���tv) velocity (r=-0.49, p=0.004 and r=-0.40, p=0.023, respectively). Peak exercise capacity was related to peak RV pressure (r=-0.56, p=0.001), E���tv (r=0.49, p=0.005), TeiC (r=-0.55, p=0.001) and TeiD (r=-0.58, p=0.001). Intraclass correlation coefficient of TeiD for intraobserver measurements was 0.90 (n=10, p<0.001, 95%CI 0.64-0.97) and for interobserver measurements was 0.79 (n=10, p=0.002, 95%CI 0.35-0.94). Conclusions: RV TeiD measured via DPD tracing of RV inflow and outflow velocity is feasible and reliable in evaluating RV dysfunction. However, to evaluate clinical usefulness of RV TeiD, further study evaluating a large number of patients with long-term follow-up is warranted.