Aortic valve stenosis
The heart has four chambers. In the lower left chamber (left ventricle), the aortic valve works like a one-way gate. When the heart pumps, the aortic valve opens to let oxygen-rich blood flow from the left ventricle into a large blood vessel called the aorta. Blood then flows through the aorta to the rest of the body.
Aortic valve stenosis means that this valve has narrowed, and it can't open all the way. The heart has to work harder to pump blood through the smaller opening. The heart can do this for many years, but over time it gets worn out. It can no longer send out as much blood as your body needs. If you don't get treatment, heart failure may develop.