Transthoracic imaging. Parasternal short-axis view of the right ventricle (RV) and the left ventricle (LV) in a 6-year old girl with idiopathic pulmonary arterial hypertension. The LV appears D-shaped due to flattening of the interventricular septum caused by increased pressure of the RV. The RV/LV ratio was derived at end-systole (red lines). For obtaining the LV eccentricity index (LVesEI), the shorter white line represents the septal-lateral dimension of the LV, whereas the long white line represents the anterior–posterior dimension.