heart ventricle septal wall thickness heart intraventricular end-systolic wall thickness 2018-05-15T17:13:43Z IVSs The thickness, width or depth of the septal wall of the heart ventricles (that is, the portion of the wall between the left and right ventricles that is shared between the two) at the end of systole when the heart muscle is maximally contracted. heart intraventricular septum end-systolic thickness jrsmith