AIMS: To quantify right ventricular (RV) function in patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after pulmonary endarterectomy (PEA). METHODS: Out of 33 patients included, 16 were evaluated clinically and with echocardiography (conventional and myocardial deformation parameters) before PEA (preop) and at 1week, 1month, 3months and 6months after PEA. RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE) as well as mid-apical and basal peak ejection strain (S) and strain rate (SR) of the RV free wall were measured. Left ventricular (LV) apical lateral wall motion was regarded as indicating changes in overall heart rocking motion (RM). Heart catheterization was performed before, within 1 week and at 6months after PEA. RESULTS: Clinical and hemodynamic parameters improved significantly after PEA. This correlated with the improvement in RVFAC, S and SR. TAPSE, on the other hand, showed a biphasic response (14.5+/-4mm preop, 8.5+/-2.7mm at 1w and 11+/-1.5mm at 6m). Changes in LV apical motion explain this finding: At baseline, TAPSE was enhanced by rocking motion of the heart due to the failing RV. Unloading the RV by PEA normalized the rocking motion and TAPSE decreased. CONCLUSIONS: RV function of CTEPH patients improves steadily after PEA. Unlike S, SR and RVFAC, this is not reflected by TAPSE due to postoperative changes in overall heart motion. Motion independent deformation parameters (S, SR) appear superior in the accurate description of regional RV function.