The Facts

Mitral valve prolapse (MVP) is a common condition that affects one of the heart's valves. It occurs in about 1 out of every 50 people and is slightly more common in women than in men. This condition can be undetected for years and doesn't usually cause serious heart problems. Most people with MVP require no treatment.

Causes

The mitral valve is the heart valve located between the upper and lower chambers of the left side of the heart. The mitral valve is made up of two flaps and controls the blood flow from the top chamber of the left side of the heart (the left atrium) to its bottom chamber (the left ventricle).

But in MVP, one or both of the flaps are too big. The valve can't close properly and will bulge out or prolapse into the left atrium. With a stethoscope, doctors may hear the soft "clicking" sound of the bulging. Sometimes, the bulging creates a little space between the flaps, which lets the blood leak backwards into the left atrium from the ventricle. This leak or regurgitation can cause a "whooshing" murmur sound that can also be heard with the stethoscope.

MVP is sometimes inherited. Some people with MVP have minor deformities of the chest, back, and spine. In rare cases, inherited diseases such as Marfan's syndrome have been associated with MVP.

Symptoms and Complications

MVP symptoms are usually minor. If you have MVP, you may feel perfectly fine or may not even know about it. Most people with MVP have no symptoms. Some of the symptoms people feel are often puzzling, since they aren't directly caused by the valve malfunction.
The symptoms of MVP include:

• irregular heartbeat or palpitations
• tachycardia, or increased heartbeats and pounding in the chest, often occurring after exercise
• chest pain that can last from seconds to hours, often when you are resting
• panic attacks such as a sudden feeling of anxiety or doom
• fatigue, dizziness, and weakness, sometimes misdiagnosed as chronic fatigue syndrome

Very few people with MVP experience complications. In rare cases, complications of MVP include:

• irregular heartbeat (arrhythmia) and chest pain (angina pectoris) – both of these conditions may be treated with medications such as beta-blockers
• endocarditis, a heart valve infection
• severe mitral regurgitation and congestive heart failure

Endocarditis is a bacterial infection of the mitral valve, which can be treated with antibiotics. People with MVP rarely develop endocarditis after having certain dental or surgical procedures that increase the risk of introducing bacteria into the blood. Preventative antibiotics are no longer routinely recommended before most dental and surgical procedures.

Making the Diagnosis

Many people have MVP and never exhibit any symptoms. If you know about your condition, it's quite likely that it was diagnosed as part of a routine checkup. With a stethoscope, doctors can detect the clicking noise or murmur associated with MVP. The diagnosis should be confirmed with an ultrasound of the heart (echocardiogram). Results from the echocardiogram can tell doctors about the extent of the mitral valve bulge and leakage.

Treatment and Prevention

Most people with MVP need no treatment, but should be checked at least every 3 to 5 years. Those who have a lot of blood leaking backwards (called mitral regurgitation) are usually monitored more closely. The American Heart Association (AHA) used to but no longer recommends giving antibiotics prior to surgery or dental work to prevent bacterial infections in people with MVP, even in those who have substantial valve leakage or valve thickening.

Complications associated with MVP can be treated accordingly; for example, endocarditis with antibiotics, and arrhythmias with medications such as beta-blockers or antiarrhythmics.

Sometimes people with severe MVP need heart surgery to either repair or replace the mitral valve. This is necessary only if you have severe backwards leakage of blood, which can cause your heart to enlarge over time and lead to heart failure or arrhythmias. If this is the case, heart surgeons may be able to repair the valve instead of replacing it with an artificial one. A repaired valve lasts longer than an artificial one and is associated with fewer long-term complications. In addition, a repaired valve also does not require the use of anticoagulants or blood thinners, which is necessary with mechanical heart valves.

After severe MVP is detected, it is hard to know the best time for it to be fixed surgically, especially if there is no significant regurgitation. This is a complex decision and your family doctor and cardiologist should continue to monitor your condition regularly.

Steven Kang, MD, Director, Cardiac Electrophysiology, Alta Bates Summit Medical Center, Stanford Healthcare, Oakland, CA. Board Certified in Cardiovascular Disease. Review provided