Mitral Valve
Prolapse
Source:
National Heart, Lung, and Blood Institute
Mitral valve
prolapse is frequently diagnosed in healthy people and is, for the most part,
harmless. Most people suffer no symptoms whatsoever from mitral valve prolapse.
Estimates are that 1 in 10 to 1 in 20 individuals has mitral valve prolapse.
It 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.
Mitral valve prolapse can be present from birth or develop at any age. It occurs in both men and women, but is more common in women. Mitral valve prolapse is one of the most frequently made cardiac diagnoses in the United States.
What is Mitral
Valve Prolapse?
Although in general healthy hearts are structurally similar, like other parts
of the body there are individual variations. 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 though
the aortic valve. In mitral valve prolapse the shape or dimensions of the
leaflets of the valve are not ideal; they may be too late and fail to close
properly or balloon out, hence the term "prolapse" when the valve leaflets
flap, a clicking sound may be heard. Sometimes the pro-lapsing of the mitral
valve allows a slight flow of blood back into the left atrium, which is called
"mitral regurgitation," and this may cause a sound called a murmur. Some
people with mitral valve prolapse 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 which come and go.
Diagnosis
Mitral valve prolapse is commonly diagnosed by listening to the sounds that
the heart makes or occasionally is discovered through echocardiographic tests.
Sometimes once a physician has
heard the characteristic sounds of mitral valve prolapse through a stethoscope,
other tests may be ordered. Echocardiography is a common and painless test
which uses sound waves of a very high frequency which travel through the layers
of the skin and muscle to produce an image of the heart which can be seen
on a screen. In this sense it is a technique similar to radar or sonar imaging.
Symptoms
The vast majority of people with mitral valve prolapse have no discomfort
whatsoever. 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 which
may or may not be related to the mitral valve prolapse.
Treatment
In most cases no treatment is needed. For a small proportion of individuals
with mitral valve prolapse beta-blockers or other drugs are used to control
specific symptoms. Serious problems are rare, can easily be diagnosed and
if necessary, treated surgically.
Preventing
Complications
The overwhelming majority of people with mitral valve prolapse are free of
symptoms and never develop any noteworthy problems. However, it is important
to understand that in some cases mitral regurgitation, that is, 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.
Historical
background
It may seem that mitral valve prolapse is becoming more common but actually
it has probably always been around and was simply less well recognized. For
instance, some historians cite the observation of "soldier's heart" made
by Dr. J.M. DaCosta during the Civil War as the first description of mitral
valve prolapse. Contemporary understanding of this condition advanced, however,
with the work in 1966 of Dr. J.B. Barlow in South Africa when he related the
characteristic sounds to the specific anatomical characteristics of the leaflets
in mitral valve prolapse. More precise identification became possible as increasingly
sophisticated diagnostic tools were available.
The increased visibility of this disorder has also come from one-time or cross-sectional studies of healthy people as well as longitudinal studies which follow individuals over years such as the Framingham Study where routine tests have shown that it is commonly present. No one knew quite how common, and unnoticed, mitral valve prolapse was until 1976 when researchers examined 100 presumably healthy young students at a woman's school. Their finding, that it occurred frequently and that as many as 1 in 10 to 1 in 20 have mitral valve prolapse, was then underscored by findings from the Framingham Study in 1983, as well as by reports from other research.
Clinical
Significance
The overwhelming majority of people with mitral valve prolapse are free of
symptoms and never develop any noteworthy problems. Whether or not there is
any discomfort, health care providers should be notified of the existence
of mitral valve prolapse so that recommendations can be made about the advisability
of using antibiotics to protect against bacterial endocarditis.
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
National Institutes of Health
National Heart, Lung, and Blood Institute
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