Background Tissue Doppler imaging (TDI) has provided an objective way to quantify global and regional left ventricular (LV) and right ventricular (RV) function with improved accuracy and greater reproducibility than conventional echocardiography. Objective This study was conducted to assess the effect of pulmonary hypertension on the right ventricular function. Methods A total of 30 patients with PHT (GP1, mean PASP 56±12mmHg, mean age 43.7±11 years ) and 30 healthy age and gender matched volunteers (GP2, mean PASP 20±12 6mmHg, mean age 45.6±10 years) underwent standard Doppler echocardiography and TDI. Systolic (Sm), early- and late-diastolic (Em and Am) peak velocities of the basal left and right ventricular segments were evaluated in the apical 4 chamber view. RV dyssynchrony was assessed by the myocardial systolic activation delay. This was defined as the difference in time to peak TDI systolic velocities between the RV basal lateral wall and basal septal and the difference in time to peak TDI systolic velocities between the RV basal lateral wall and LV basal lateral wall. Also, RA area, RV end-diastolic (RVEDA) and end-systolic areas (RVESA) were measured to calculate RV fractional area (RAFAC) change from the same apical 4-chamber view. Results Gp1 had increased RA area (25.3±5 vs 11±1cm², P