Valvular heart disease is when any valve in the heart has damage or is diseased. There are several causes of valve disease.
- The normal heart has four chambers (right and left atria, and right and left ventricles) and four valves (Figure 1).
- The mitral valve, also called the bicuspid valve, allows blood to flow from the left atrium to the left ventricle.
- The tricuspid valve allows blood to flow from the right atrium to the right ventricle.
- The aortic valve allows blood to flow from the left ventricle to the aorta.
- The pulmonary valve allows blood to flow from the right ventricle to the pulmonary artery.
The valves open and close to control or regulate the blood flowing into the heart and then away from the heart. Three of the heart valves are composed of three leaflets or flaps that work together to open and close to allow blood to flow across the opening. The mitral valve only has two leaflets (Figure 2).
Healthy heart valve leaflets are able to fully open and close the valve during the heartbeat, but diseased valves might not fully open and close. Any valve in the heart can become diseased, but the aortic valve is most commonly affected.
Diseased valves can become “leaky” where they don’t completely close; this is called regurgitation. If this happens, blood leaks back into the chamber that it came from and not enough blood can be pushed forward through the heart.
The other common type of heart valve condition happens when the opening of the valve is narrowed and stiff and the valve is not able to open fully when blood is trying to pass through; this is called stenosis.
Sometimes the valve may be missing a leaflet—this more commonly involves the aortic valve. If the heart valves are diseased, the heart can’t effectively pump blood throughout the body and has to work harder to pump, either while the blood is leaking back into the chamber or against a narrowed opening. This can lead to heart failure, sudden cardiac arrest (when the heart stops beating), and death.
