The volume of blood pumped from the heart (left ventricle) into the systemic aorta in one minute is called the cardiac output. It is also called minute volume. It is calculated as the product of stroke volume (amount of blood pumped by left ventricle each time it contracts) and rate of heartbeat, i.e., Cardiac output = Stroke volume x Rate of heart beat =70ml× 75 times/minute =5250ml/ minute or 5.25 litres / minute.