Mitral-valve prolapse (MVP) is frequently
diagnosed in healthy people and is, for the most part, harmless. Most
people suffer no symptoms at all. New estimates are that about 2
percent of the adult population has the condition.
MVP is also called floppy valve
syndrome, Barlow's or Reid-Barlow's syndrome, ballooning mitral valve,
midsystolic-click-late systolic murmur syndrome, or click murmur
syndrome. MVP can be present from birth or develop at any age and
occurs equally in both men and women. MVP is one of the most
frequently made cardiac diagnoses in the United States.
What
it is
The mitral valve is the heart valve
between the left atrium and left ventricle. It has two flaps, called
leaflets or cusps, which open and close when the heart contracts
(beats) and rests.
The heart's valves work to maintain the
flow of blood in one direction, ensuring proper circulation. The
mitral valve controls the flow of blood into the left ventricle.
Normally, when the left ventricle contracts, the mitral valve closes
and blood flows out of the heart through the aortic valve and into the
aorta to start its journey to all other parts of the body.
In MVP, the shape or dimensions of the
leaflets of the valve are not ideal; they may be too large and fail to
close properly or they balloon out, hence the term "prolapse." When
the valve leaflets flap, a clicking sound may be heard. Sometimes the
prolapsing of the mitral valve allows a slight flow of blood back into
the left atrium. This is called "mitral regurgitation," and may cause
a sound called a murmur. Some people with MVP have both a click and a
murmur and some have only a click. Many have no unusual heart sounds
at all; those who do may have clicks and murmurs that come and go.
Symptoms
The vast majority of people with MVP
have no discomfort at all. Most are surprised to learn that their
heart is functioning in any way abnormally. Some individuals report
mild and common symptoms such as shortness of breath, dizziness, and
either "skipping" or "racing" of the heart. More rarely, chest pain is
reported. However, these are symptoms that may or may not be related
to the MVP.
Diagnosis
Sometimes, once a physician has heard
the characteristic sounds of MVP through a stethoscope, other tests
may be ordered. Echocardiography is a common and painless test
that uses very high frequency sound waves. The sound waves travel
through the layers of the skin and muscle to produce an image of the
heart that can be seen on a screen. In this sense, it is similar to
radar or sonar imaging.
Initially, "M-mode" echocardiography
was used to diagnose MVP in the 70's and 80's. It resulted in a
lot of false positive diagnoses. The National Institute of
Health recommends that if you were diagnosed with mitral valve
prolapse since the 1970's that you may want to discuss it with your
doctor because you may not have MVP after all.
Treatment
In most cases, no treatment is needed.
For a small proportion of individuals with MVP, beta-blockers or other
drugs are used to control specific symptoms and some blood pressure
lowering drugs may be used to treat mitral regurgitation.
Serious problems are rare, can easily
be diagnosed and, if necessary, treated surgically.
Course of the disease
The overwhelming majority of people
with MVP are free of symptoms and never develop any noteworthy
problems. However, it is important to understand that in some cases
mitral regurgitation, the flow of blood back into the left atrium, can
occur.
Where mitral regurgitation has been
diagnosed, there is an increased risk of acquiring bacterial
endocarditis, an infection in the lining of the heart. To prevent
bacterial endocarditis many physicians and dentists prescribe
antibiotics before certain surgical or dental procedures.
Patients with significant mitral
regurgitation should be followed more closely by their physician so
that medical therapy and, if necessary, surgery, can be pursued at the
appropriate time.
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