Mitral valve collapse is the most common heart valve problem, afflicting between 4 percent and 18 percent of all people. Mitral valve collapse occurs when the valve between the left atrium of the heart and the left ventricle does not close properly and allows blood to flow backward from the left ventricle into the left atrium. The backflow of blood is referred to as mitral valve regurgitation. The cause of mitral valve collapse is not known.
The heart is composed of four chambers, the left and right atria and the left and right ventricles. In the body, oxygen-starved blood enters the right atrium of the heart, passes through the tricuspid valve and into the right ventricle. The blood is then pushed from the right ventricle into the lungs, where it is oxygenated. The oxygen-rich blood returns to the heart through the left atrium, passes through the mitral valve into the left ventricle and is then forced throughout the body. The mitral and tricuspid valves are essential in preventing backflow of blood in the heart.
The mitral valve is composed of two tissue flaps that clamp down on the opening between the left atrium and left ventricle like a watertight gate. There are two ways a mitral valve can malfunction: the valve gates can be longer and thicker than necessary, preventing a tight seal; or the valve flaps may be flimsy, stretching more than necessary and making a strong closure impossible.
Mitral valve collapse is initially diagnosed by listening to the heart with a stethoscope. A malfunctioning mitral valve will produce a clicking sound as the blood is shunted through it. Confirmation of mitral valve collapse is sometimes done using an echocardiogram or electrocardiogram. A stress test will sometimes be ordered to ensure that the mitral valve collapse will not interfere with exercise.
Most symptoms related to mitral valve collapse are benign. People often do not even know they have a valve defect. Other times, the symptoms are more severe and noticeable. These symptoms include heart palpitations or arrhythmias, severe mitral valve regurgitation or heart infections known as endocarditis.
Mitral valve collapse sometimes results in arrhythmias or irregularly slow or fast heart beats. When this problem is severe, it is treated with beta blockers. Beta blockers are drugs that slow the heart rate, decreasing the vigor with which the heart beats.
When mitral valve collapse causes severe regurgitation or backflow of blood within the heart, surgery may be required to prevent complications or heart failure. The surgery will either repair the existing valve or replace it. A malfunctioning mitral valve is repaired by reshaping or resizing the valve flaps so they close completely. When the valve cannot be repaired and needs to be removed, it can be replaced by either a mechanical valve or a donated tissue valve.
Endocarditis is an infection of the endocardium, or membranous tissue that lines the heart. The backflow of blood that occurs with a malfunctioning mitral valve makes the heart more susceptible to infection. To prevent endocarditis, antibiotics are often prescribed prior to surgery and even before any dental procedures.