Mitral Valve Prolapse
Mitral valve prolapse, (MVP), is a condition in which the mitral valve balloons back into the left atrium when the heart pumps. The mitral valve separates the heart's left atrium, or upper chamber, from the left ventricle, or lower chamber.
What is going on in the body?
The left atrium receives blood from the lungs and passes it through the mitral valve to the left ventricle. The left ventricle pumps blood to the rest of the body. The mitral valve normally remains firm when the left ventricle contracts.
For reasons that are not clear, the tissues that make up the valve sometimes thicken and weaken. When that occurs, the valve balloons back into the left atrium when the left ventricle pumps. This sometimes allows blood to leak backward, a condition known as chronic mitral regurgitation.
Mitral valve prolapse is generally not serious. In both men and women, the "cords" (the thin, stringlike structures that attach the valve to the left ventricular wall) can sometimes rupture for no known reason. This rupture causes more severe leakage.
What are the causes and risks of the condition?
The cause of mitral valve prolapse is unknown. It is more common in people with low body weight and low blood pressure. It is also more common in those who were born with an indentation at the lower part of the breastbone, called pectus excavatum or funnel chest.
About 3% to 5% of the population are diagnosed with mitral valve prolapse. On autopsy, MVP is identified in 7% of the population. Mitral valve prolapse is rare before puberty and usually develops at 10 to 16 years of age. Women have MVP three times more often than men.
Mitral valve prolapse occurs more commonly in individuals with certain diseases and conditions, including the following:
- congenital heart disease, such as atrial septal defect
- history of mitral valve surgery
- infection of the heart following rheumatic fever
- muscle diseases, such as Duchenne muscular dystrophy
- polycystic kidney disease
- systemic lupus erythematosus, an autoimmune disorder that affects many body systems
What can be done to prevent the condition?
There are no known ways to prevent mitral valve prolapse. Once MVP is diagnosed, a person may be able to reduce symptoms by avoiding things that trigger symptoms, such as:
- emotional stress
- foods containing sugar
- missing meals
- stimulants, such as over-the-counter diet medications
- unusual physical activity
How is the condition diagnosed?
Mitral valve prolapse is usually diagnosed in the course of a physical examination. The healthcare provider, using a stethoscope, may hear an abnormal heart sound such as a click or murmur. The provider can make the click and murmur occur earlier in the heartbeat by having the person stand or tighten his muscles as if having a bowel movement.
The provider may order an echocardiogram, which is a special imaging test of the heart done with ultrasounds. It can show a thickened valve that balloons into the left atrium. A Doppler echocardiogram can show blood flowing backward through the valve into the left atrium.
Long Term Effects
What are the long-term effects of the condition?
Mitral valve prolapse can progress with time to the point that mitral regurgitation occurs or worsens. This rarely means that the valve must be replaced.
Other long-term effects of MVP include the following:
- endocarditis, an infection of the heart lining
- rapid or irregular heartbeats
- sudden death, which is very rare and usually associated with severe mitral regurgitation, distortion of the valve leaflets, or other serious heart conditions.
What are the risks to others?
Mitral valve prolapse is not contagious and poses no risk to others. MVP does tend to run in families.
What are the treatments for the condition?
In most cases, no treatment is needed for mitral valve prolapse. The person needs to be reassured that this condition is not serious. If a person has mitral regurgitation as well as mitral valve prolapse, antibiotics may be given before various medical and dental procedures. This reduces the risk of getting an infected mitral valve.
People with MVP can live a healthier lifestyle by following these guidelines:
- Avoiding smoking.
- Drinking plenty of fluids.
- Eating a healthy diet following the food guide pyramid.
- Following the healthcare provider's recommendations for exercise.
- Getting plenty of sleep and rest.
- Limiting caffeine and alcohol intake.
- Limiting intake of fats and sugars, particularly large amounts at one time.
- Managing stress.
The healthcare provider may prescribe medications called beta-blockers for people who develop rapid or irregular heartbeats. Common beta-blocker medications include metoprolol (i.e., Lopressor, Toprol XL) and atenolol (i.e., Tenormin).
These individuals should drink plenty of fluids to avoid dehydration. They should limit their caffeine intake.There is a great deal of controversy regarding recommendations for exercise in people with MVP. Individuals with MVP should discuss their risk factors and exercise regimen with the healthcare provider.
What are the side effects of the treatments?
Antibiotics can cause stomach upset and allergic reactions. Beta-blockers can cause slow heart rates and low blood pressure. They may also cause depression, erectile dysfunction, and unpleasant dreams.
What happens after treatment for the condition?
People with mitral valve prolapse should discuss their exercise regimen with the healthcare provider.
How is the condition monitored?
Regular physical exams are usually enough to check for the development of mitral regurgitation which, if found, can be evaluated further with an echocardiograms. Any new or worsening symptoms should be reported to the healthcare provider.
Scientific American Medicine 2000 (updated monthly)
Medical Knowledge Self Assessment Program (MKSAP 11) 1998