Mitral valve prolapse (MVP) is the most common heart valve abnormality in the United States, affecting between 2 and 3 percent of the population. It occurs when the Mitral valve, which is located between the upper and lower chambers on the left side of the heart, has structural alterations. The mitral valve controls blood flow between these two chambers. It has two flaps that swing open and shut as blood travels from the upper chamber to the lower chamber on the left side of the heart.

In individuals with mitral valve prolapse, these flaps buckle back into the left atrium when the left ventricle contracts in a way that is similar to an open parachute. This action can prevent the valve from forming a tight seal between the chambers. This condition can be worsened in situations where the left ventricular cavity is smaller, such as when a patient is dehydrated or during standing. When a person is upright, the blood pools in the legs from gravity and less is present in the heart chamber. Many individuals with mitral valve prolapse have no significant valve leakage or hemodynamic abnormalities.

In the majority of cases, mitral valve prolapse causes no serious problems and does not require treatment. In a small percentage of cases, however, mitral valve prolapse can cause serious cardiac problems, including mitral valve regurgitation (when blood flows the wrong way), an infection of the heart valves and heart rhythm abnormalities. Although constant treatment is typically unnecessary for patients with mitral valve regurgitation, they may be given antibiotics before surgery or dental procedures to prevent infection of the heart valves. Physicians may choose to monitor a patient with mitral valve prolapse to make sure their condition is not worsening.