Heart Valve Disease
Each of the four valves (mitral and aortic on the left side of the heart, and tricuspid and pulmonary on the right side) keeps the blood flowing in one direction, like one-way gates. They open when the pressure of the blood pushes them in the forward direction, and they close when the pressure on the other side of the valve pushes them back. Diseased valves may be too stiff to open easily, obstructing blood flow, or they may fail to close completely, permitting leakage.
If a valve opening becomes narrow and tight (stenotic), blood flow through it is decreased, causing the blood behind it to back up as if at a dam. This backup leads to symptoms of congestive heart failure and angina.
If a valve fails to close properly, blood will leak back in the wrong direction—called "regurgitation." As a result, the heart chambers eventually may enlarge and pump inefficiently.
The causes of valve disease include congenital defects, infections and calcium deposits that accumulate on the valves as you age. It may take decades before valve damage shows up because the body compensates or adapts.
Valves may also be damaged by rheumatic fever, which may develop after an untreated strep throat infection. The disease may temporarily inflame the heart and scar the valves. Although rheumatic fever is not nearly as common in the United States as it was 40 years ago before the widespread use of penicillin, several outbreaks were reported in the 1980s; and it's still common in underdeveloped countries. When valve disease is advanced, surgeons can remove the diseased valves and replace them with artificial ones.
Damaged or weakened valves are also vulnerable to infections—called endocarditis—of the endocardium, the membrane that lines the inside of the valves. The infection is caused by bacteria or other organisms. Endocarditis can occur whenever such organisms circulate in the bloodstream. It's more common in people with valve disease because bacteria and other germs tend to settle and multiply on misshapen heart valves where blood flow is turbulent.
Mitral Valve Prolapse
Mitral valve prolapse is a mild abnormality of a heart valve, usually detected by the presence of a murmur, or a clicklike sound heard with a stethoscope. The condition is common, affecting about 2 million Americans. About 80 percent of cases occur in women.
The mitral valve is a two-leaflet, parachutelike valve that protects the heart from ejecting blood backward into the lungs. The valve ensures that blood flows forward (towards the body) during each heartbeat. Mitral valve prolapse occurs when the chords holding the valve in place become elongated. It progresses gradually and often has no known cause.
In mitral valve prolapse, the valve leaflets billow backward as the heart contracts. In mild cases, the physician can hear a "click-murmur" which signals the abnormal closure pattern of the valve. Some people discover they have the condition when they begin experiencing chest pain, usually not related to exertion, at a young age.
In the most severe cases, improper closure of the mitral valve causes it to leak. The murmur increases, and symptoms of congestive heart failure occur, such as shortness of breath, fatigue, rapid heart rhythms (atrial fibrillation) and ankle swelling. Once the heart dilates, or symptoms become apparent, surgery is necessary.
As long as congestive heart failure symptoms do not occur, surgery to correct mitral valve prolapse is usually not needed. Treatment consists only of careful history taking and examination to screen for heart-rhythm abnormalities or evidence of a heart murmur.
In severe cases when symptoms of congestive heart failure occur, treatment may include replacing or reconstructing the valve. Although repairing the valve is preferable, multiple elongated chords are hard to fix reliably. Most commonly, people with severe forms of mitral valve prolapse require a replacement valve.
If you have mitral valve prolapse, rest assured that the condition is usually not serious. Millions of people have mild disease and need nothing further done. If advancing shortness of breath, palpitations or chest pains occur with exertion, then consult your doctor.