Objective To quantify the right ventricular (RV) function in patients with left heart disease (LHD) related pulmonary hypertension (PH) by two-dimensional speckle tracking imaging (2D-STI),and explore its potential value in diagnosis of reactive PH.Methods Forty healthy volunteers and 65 patients with LHD related PH were enrolled.PH patients were further divided into two subgroups according to pulmonary vascular resistance(PVR):passive PH group and reactive PH group.A complete 2D-STI derived longitudinal strain of RV free wall was performed,and the basal,middle,apical longitudinal peak systolic strain (LS) and RV free wall global LS (RVLSbas,RVLSmid,RVLSapi and RVLSfw) were measured.Results Compared to control group,RVLSbas and RVLSfw in reactive PH group decreased significantly (all P ＜0.05).Compared to passive PH group,RVLSbas and RVLSfw in patients with reactive PH decreased significantly (all P ＜0.05).The differences of RVLSbas and RVLSfw between control group and passive PH group had no statistical significance (all P ＞0.05).No significant differences in etiology and left ventricular ejection fraction (LVEF) were observed between PH subgroups (all P ＞0.05).The area under the ROC curve of RVLSbas in predicting reactive PH was 0.93,the cut-off value was-21.86,and the sensitivity and specificity were 83 ％ and 89 ％,respectively.The area under the ROC curve of RVLSfw was 0.79,the cut-off value was-13.84,and the sensitivity and specificity were 59％ and 89％,respectively.Conclusions 2D-STI can realize quantitative assessment of RV function in patients with LHD related PH.RVLSbas and RVLSfw may have important clinical value in diagnosing patients with reactive PH,and differential diagnosis value between patients with passive PH and patients with reactive PH.