Speckle tracking imaging (STI) was employed to investigate the effect of right ventricular (RV) volume and pressure overload on left ventricular (LV) rotation and twist in 35 patients with atrial septal defect (ASD), 18 of which with pulmonary hypertension, and 21 healthy subjects serving as controls. The peak rotations of 6 segments at the basal and apical short-axises and the average peak rotation and interval time of the 6 segments in the opposite direction during early systolic phase were measured respectively. LV twist versus time profile was drawn and the peak twist and time to peak twist were calculated. LV ejection fraction (EF) was measured by Biplane Simpson. Compared to ASD patients without pulmonary hypertension and healthy subjects, the peak rotations of posterior, inferior and postsept walls at the basal level were lower (P<0.05), and the average counterclockwise peak rotation of 6 segments at the basal level during early systolic phase was higher (P<0.05), and the average interval time was delayed (P<0.05). LV peak twist was also lower (P<0.05), and had a significant negative correlation with pulmonary arterial systolic pressure (r=-0.57, P=0.001). No significant differences were found in LVEF among the three groups. It was suggested that although RV volume overload due to ASD has no significant effects on LV rotation and twist, LV peak twist is lower in ASD patients with pulmonary hypertension. Thus LV twist may serve as a new indicator of the presence of pulmonary hypertension in ASD patients.