Objective To explore the value of peak systolic displacement of tricuspid annulus(TAD)in evaluation of right ventricular systolic function by speckle tracking imaging(STI).Methods The study population consisted of 24 healthy subjects(control group)and 16 patients with congestive heart failure(CHF).The apical four-chamber view was obtained and imput to Qlab 6.0 workstation. The TAD at the right ventricular free wall (TADla)and the midpoint of tricuspid annulus(TADmid)were measured and calculated automatically.Right ventricular ejection fraction(RVEF)was measured by real-time three-dimensional echocardiography.The correlation of displacement parameters with RVEF was analyzed.Results In all 40 subjects, the mean value of TADla was(19.3±5.9)mm with s range from 7.8 to 28.4 mm while the mean value of TADmid was(15.3±4.6)mm with a ranging from 7.2 to 22.2 mm.The parameters in CHF group were significantly lower than those of the control group(P<0.01).TADla and TADmid showed an excellent correlation with RVEF(r=0.87 and 0.91 respectively,P<0.01).The cut-off value of TADla for RVEF<45%was 17.2 mm with a sensitivity of 89%and a specificity of 93% while the cut-off value of TADmid for RVEF<45% was 13.1 mm with a sensitivity of 96%and a specificity of 1 00%.Conclusions TAD by STI showed an excellent correlation with RVEF, and it may be a new promising method for routine evaluation of right ventricular systolic function.