Cardiology. The amount of blood pumped out of the heart per contraction. Ventricular stroke volume (SV) is the difference between the ventricular end-diastolic volume and the end-systolic volume. The end-diastolic volume is the filled volume of the ventricle prior to contraction and the end-systolic volume is the residual volume of blood remaining in the ventricle after ejection. In a typical heart, the end-diastolic volume is about 120 ml of blood and the end-systolic volume about 50 ml of blood. The difference in these two volumes, 70 ml, represents the stroke volume. The product of heart rate and stroke volume is the cardiac output.