Objective: Patients with acute pulmonary thromboembolism (PTE) and right ventricular (RV) dysfunction may benefit from thrombolytic therapy. We sought to determine the usefulness of RV strain imaging in the demonstration of improvement in RV function in response to thrombolytic therapy.Methods: This study prospectively enrolled 32 consecutive patients who received thrombolytic therapy due to diagnosis of PTE. The diagnosis was verified by 256-slice multi-detector computed tomography. Right ventricular function parameters were assessed via conventional and tissue Doppler imaging echocardiography before and 2-3 days after thrombolytic therapy.Results: Echocardiographic study showed that mean tricuspid annular plane systolic excursion and RV fractional shortening area change increased significantly from 13.32 +/- 3.46 mm to 18.18 +/- 4.77 mm and from 22.95 +/- 9.73% to 36.20 +/- 10.17%, respectively, before compared to after treatment. A significant decrease was observed in systolic pulmonary artery pressure from 61.57 +/- 10.49 mm Hg to 38.78 +/- 14.27 mm Hg. Mid-ventricular peak systolic strain and strain rate of the RV also significantly improved (-6.08 +/- 11.19% to -19.13 +/- 9.51% and -0.72 +/- 0.96 S(-1) to -1.54 +/- 0.66 S(-1), respectively).Conclusions: Tissue Doppler-derived peak systolic strain of RV mid-ventricular wall may be potentially useful in the serial quantification of improvement in RV function in response to thrombolytic therapy in acute PTE.