Acute pulmonary embolism (APE) is known as one of the major causes of sudden death. However, high level of mortality caused by APE can be reduced, if detected in early stages of development. Hence, biomarkers capable of early detection of APE are of utmost importance. This study investigates how APE affects the biomechanics of the cardiac right ventricle (RV), taking one step towards developing functional biomarkers for early diagnosis and determination of prognosis of APE. To that end, we conducted a pilot study in pigs, which revealed the following major changes due to the severe RV afterload caused by APE: (1) waving paradoxical motion of the RV inner boundary, (2) decrease in local curvature of the septum, (3) lower positive correlation between the movement of inner boundaries of the septal and free walls of the RV, (4) slower blood ejection by the RV, and (5) discontinuous movement observed particularly in the middle of the RV septal wall.