Stroke Volume

Stroke volume is determined by four factors:

1. The volume of venous blood returned to the heart
2. Ventricular distensibility, or the capacity to en-large the ventricle
3. Ventricular contractility
4. Aortic or pulmonary artery pressure (the pressure against which the ventricles must contract)

source: http://btc.montana.edu/olympics/physiology/cf04.html