The Heart Valves
There are four valves that control the flow of blood through the four chambers of the heart. They are like one-way doors that keep the blood moving in one direction and prevent it from backing up into the chamber from which it came. When the heart beats, the valves close to keep the blood from flowing backward.
What causes a heart valve problem?
The job of the four valves is to ensure that the blood flows forward as your heart contracts and relaxes. The valves are made of thin but extremely strong flaps of tissue that open and close as your heart beats. A human heart beats more than 100,000 times a day. The valves must flex, stretch and hold back pressure hundreds of millions of times in an average lifetime. As we age the valves can weaken or harden.
The mitral and aortic valves on the left side of the heart are most commonly affected by aging because pressures are higher on the left side. The right heart valves can be damaged by infection or by back-pressure from the lungs because of lung disease. When disease causes the valves to harden and weaken, they will not open properly and the blood flow is blocked.
Three types of valve defects occur:
- Stenosis - A valve may become stiff or narrowed, restricting the amount of blood flowing through the heart and forcing it to work harder to pump enough blood to meet the body's needs. This condition can be present at birth, or it may occur gradually as a result of the formation of scar tissue or calcium deposits.
- Regurgitation - A valve may lose its shape, become overstretched, or lose the ability to close completely. Blood then leads back into the chamber from which it was pumped (regurgitation). The extra blood will eventually cause the overloaded chamber to stretch and enlarge.
- Prolapse - A part of the valve billows backward with each heartbeat, it may not close smoothly or evenly. A clicking sound may be heard through a stethoscope as the valve billows up. This problem most often occurs inthe mitral valve. It is more common in women and usually does not cause serious complications.
Valve defects can lead to heart failure, which occurs when the heart cannot pump efficiently enough to deliver the correct amount of blood to the tissues and organs these other parts of the body then function less effectively. In addition, blood that should be pumped out of the heart instead backs up into the lungs.