heart ventricle septal wall thickness heart intraventricular end-diastolic wall thickness 2018-05-15T17:12:15Z IVSd 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 diastole when the heart muscle is maximally relaxed. heart intraventricular septum end-diastolic thickness jrsmith