What Causes Preload

Preload is increased by the following: Increased central venous pressure (CVP), e.g., from decreased venous compliance due to sympathetic activation; increased blood volume; respiratory augmentation; increased skeletal pump activity. Increased ventricular compliance. Increased atrial contraction.

What affects preload?

Preload is affected by venous blood pressure and the rate of venous return. These are affected by venous tone and volume of circulating blood. Preload is related to the ventricular end-diastolic volume; a higher end-diastolic volume implies a higher preload.

Where does preload occur?

Preload, also known as the left ventricular end-diastolic pressure (LVEDP), is the amount of ventricular stretch at the end of diastole. Think of it as the heart loading up for the next big squeeze of the ventricles during systole.