The valve between the lower left heart chamber and the body's main artery has two flaps instead of three.

Bicuspid aortic valve is a heart condition present at birth, also called a congenital heart defect. The aortic valve has two flaps instead of three. Valve flaps, called cusps, make sure blood flows in the correct direction. Changes to the aortic valve can cause blood to flow backward. It also may lead to narrowing of the valve.

Symptoms may happen if the valve gets narrow. Symptoms also can happen if blood leaks backward across the valve. Symptoms may include chest pain, fainting, shortness of breath or difficulty exercising.

Medicines may be given to treat symptoms. Surgery may be needed to repair or replace the aortic valve.