When the heart contracts, the mitral valve, located between the left atrium and ventricle, opens to allow the passage of blood into the left ventricle. In mitral valve prolapse, the valve has malformations of the leaflets that open and the strings, or chordae, that support the valve. A small amount of blood leaks backward, called regurgitation, as a result of the leaflets not meeting perfectly as they close.
While once considered a defect, some degree of mitral valve malformation is now thought to be a normal variation. In about 95% of cases, benign mitral valve prolapse never necessitates surgery, though physicians may hear a significant murmur with a stethoscope. Diagnosis of mitral valve prolapse, even when mild, is important. Even those with a very mild form should probably take antibiotics before dental exams and procedures to prevent bacterial endocarditis.
Mitral valve prolapse does not pose problems for infants, unless it is severe or associated with other congenital heart defects, but it tends to worsen with age. Symptoms of this condition may be recognized during the teenage years, or may not be noticed until a person is well into their second or third decade.
Symptoms include arrhythmia, fatigue, shortness of breath, and chest pain. Symptoms do not necessarily indicate the severity of mitral valve prolapse. In some cases, mild prolapse results in symptoms but does not require treatment. In other situations, prolapse may be significant but not have many symptoms.
When treatment for mitral valve prolapse is required, several options are considered, the first being medications to improve heart function and control heart rhythm. If there is blockage in the valve, the minimally invasive balloon valvuloplasty may be attempted to open up the passageway of the valve and prevent blood from backing up in the left atria. Balloon valvuloplasty is not generally successful, as mitral valve prolapse tends to recur.
If possible, a cardiothoracic surgeon will try to repair the valve. He or she may separate the leaflets if necessary, and also shorten the chordae to create a more effective valve. Frequently, though, surgeons elect to replace the valve completely. The new valve may be either a porcine or bovine valve, or often a mechanical valve.
Porcine and bovine valves are not as viable as mechanical valves. They have the advantage of only requiring blood thinners for a few months post-operatively. Mechanical valves require taking blood thinners, like warfarin, for life. This can be particularly difficult for young children, as the levels of warfarin must be consistently monitored.
Mitral valve prolapse has been linked to several causes. Rheumatic fever can damage the mitral valve and surrounding heart tissue. Mitral valve prolapse can be a congenital condition, or it can be caused by bacterial endocarditis. There is some evidence to suggest that congenital mitral valve prolapse may be genetic, as it tends to be present in more than one family member. If you have a family history of mitral valve prolapse, inform your physician, as the problem can be easily diagnosed through echocardiogram.