Section 7: Factors affecting Cardiac Output

Cardiac output can be affected by heart rate and stroke volume.

Stroke volume is influenced by Preload, Afterload and Contractility.

Preload is the effect of stretching in the ventricles prior to contraction. It is related to volume of blood entering the ventricles. An increase in preload would increase in stroke volume.

Afterload is the force or resistance that the ventricles must overcome to eject the blood around the body. An increase in afterload would decrease in stroke volume.

Contractility is the strength of the contraction of the ventricles. Increase in cardiac contraction, increase in stroke volume.