aortic valve

The aortic valve is the exit gate from the heart's main pump out to the body. Think of it as a three-petal flower that springs open when the left ventricle squeezes, letting blood rush into the aorta, then folds shut so none of it leaks back.

It guards the outlet from the left ventricle into the aorta and normally has three cup-shaped leaflets (semilunar cusps). During each heartbeat it opens to release the stroke volume into the systemic circulation; its sharp closure produces part of the second heart sound that doctors hear through a stethoscope.

The aortic valve is the one most often affected by age-related disease. Over decades the leaflets can stiffen and calcify, narrowing the opening (aortic stenosis), which forces the left ventricle to work harder. Some people are born with only two leaflets (a bicuspid aortic valve), which tends to wear out and cause problems earlier in life.