Changes in interventricular septum with right ventricular (RV) pressure or volume overload

Serial stop-frame short-axis two-dimensional echocardiographic images of the left ventricle at the mitral chordal level with diagrams from a patient with isolated right ventricular (RV) pressure overload due to primary pulmonary hypertension (A) and from a patient with isolated RV volume overload due to tricuspid valve resection (B). Whereas the left ventricular (LV) cavity maintains a circular profile throughout the cardiac cycle in normal subjects, in RV pressure overload, there is leftward ventricular septal (VS) shift and reversal of septal curvature present throughout the cardiac cycle with most marked distortion of the left ventricle at end-systole. In the patient with RV volume overload, the septal shift and flattening of VS curvature occurs predominantly in mid to late diastole with relative sparing of LV deformation at end-systole.