What is mitral valve prolapse?
Mitral valve prolapse (also known as "click murmur syndrome" and "Barlow's syndrome") is the most common heart valve abnormality. The condition is slightly more prevalent in women than in men. The mitral valve is one of the four heart valves. A normal mitral valve consists of two thin leaflets, located between the left atrium and the left ventricle of the heart. Mitral valve leaflets, shaped like parachutes, are attached to the inner wall of the left ventricle by a series of strings called "chordae." When the ventricles contract, the mitral valve leaflets close snugly and prevent the backflow of blood from the left ventricle into the left atrium. When the ventricles relax, the valves open to allow oxygenated blood from the lungs to fill the left ventricle.
In patients with mitral valve prolapse, the mitral apparatus (valve leaflets and chordae) becomes affected by a process called myxomatous degeneration. In myxomatous degeneration, the structural protein collagen forms abnormally and causes thickening, enlargement, and redundancy of the leaflets and chordae. Blood normally flows through the mitral valve from the left upper chamber (left atrium) to the left lower chamber (left ventricle) of the heart. When the ventricles contract, the redundant leaflets prolapse (flop backwards) into the left atrium, sometimes allowing leakage of blood through the valve opening (mitral regurgitation) back into the left atrium. When severe, mitral regurgitation can lead to heart failure and abnormal heart rhythms. Most patients are totally unaware of the prolapsing of the mitral valve. Others may experience a number of symptoms discussed below.
The mitral valve prolapse (MVP) syndrome has a strong hereditary tendency, although the exact cause is unknown. Affected family members are often tall, thin, with long arms and fingers, and straight backs. It is seen most commonly in women from 20 to 40 years old, but also occurs in men.