After contraction, how much blood normally remains in the ventricle?

1. Ventricular systole starts from an EDV of about 130 mL. 2. A stroke volume of 70 to 80 mL leaves 50 to 60 mL of blood in the ventricle after contraction. 3. That remainder is the end systolic volume, so the ventricle never empties completely. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 19 "The Cardiovascular System: The Heart", section 19.3 | Cardiac Cycle_