Dual Pulsed-Wave Doppler Tracing of Right Ventricular Inflow and Outflow: Single Cardiac Cycle Right Ventricular Tei Index and Evaluation of Right Ventricular Function

BACKGROUND AND OBJECTIVES The reliability and usefulness of the right ventricular (RV) Tei index (RTX) remains controversial because it has not been possible to simultaneously measure RV inflow and outflow. However, dual pulsed-wave Doppler (DPD) enables flow velocities to be obtained at different sampling sites simultaneously. In this study we evaluated the feasibility and reliability of RTX values obtained by DPD (RTX(DPD)). SUBJECTS AND METHODS Forty-one patients who underwent cardiac catheterization and echocardiography for RV volume or pressure overloading conditions were evaluated. Symptom-limited exercise treadmill testing with expired gas analysis was performed and maximal exercise capacity was measured. RESULTS RTX by conventional flow Doppler (RTX(CFD), 0.262±0.164) was similar to RTX(DPD) (0.253±0.117, p=NS), whereas RTX by tissue Doppler echocardiography (RTX(TDE), 0.447±0.125) was significantly larger than RTX(DPD) (p<0.001). Based on multiple regression analysis, maximal exercise capacity was independently related to RTX(DPD) (β=-0.60, p<0.001), mid-RV dimension (β=-0.26, p=0.012), left ventricular ejection fraction (β=0.22, p=0.023), and early diastolic tricuspid annular velocity (β=0.21, p=0.048). CONCLUSION It is feasible and reliable to evaluate RV function using RTX(DPD) values. However, to evaluate the clinical usefulness of RTX(DPD), additional studies are required with a large number of patients and long-term follow-up.