Cardiac output is the amount of blood the heart pumps.
It is expressed in liters/minute.
It is continuously adjusted so that the cardiovascular system operates to meet the body’s moment-to-moment movement of needed blood.
It is equal to the product of the stroke volume and the number of beats per minute (heart rate).
Changes in heart rate and stroke volume (and therefore cardiac output) can be accomplished by alterations in autonomic nerve activity to the heart and by alterations in ventricular filling.