Mitral Valve Prolapse

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Mitral Valve Prolapse: The Most Common Heart Valve Abnormality

The most common heart valve abnormality is called mitral valve prolapse

(MVP), which affects between 5 and 20 percent of the population. It is more

commonly found in women than men and can go undetected for years, as

symptoms usually do not occur until adolescence or even adulthood. MVP is

most commonly diagnosed among patients between the ages of 20 and 40.

What is it?

Mitral valve prolapse is a condition of the mitral valve, a two-flapped

heart valve between the left atrium and left ventricle. In MVP, one or both

of the valve flaps are too large, and the mitral valve does not close evenly

with each heartbeat. Because of this imperfect closing, the valve itself

slightly balloons back into the left atrium, sometimes causing what is known

as a " click " . With the flap there may sometimes be a slight backward leaking

of blood (regurgitation) as well, resulting in a heart murmur.

Mitral valve prolapse seems to be an inherited disorder, although the

precise genes are not known. If proper precautions are taken (see below) it

will not affect life expectancy, and generally has no impact on normal

activities.

What are the symptoms?

Approximately 60 percent of individuals with MVP never exhibit any symptoms.

Generally, a stressful situation (childbirth, change in job situation, viral

illness) brings on symptoms which ordinarily would not be present. Some of

these symptoms include the following:

* Irregular heartbeat or palpitations, particularly when lying on the

left side

* Tachycardia, increased heartbeats or pounding of the chest, often after

exertion

* Non-specific chest pain lasting from a few seconds to several hours,

occurring at rest rather than during exertion

* Panic attack, a sudden feeling of anxiety or doom

* Fatigue and weakness, even after slight exertion (including minor

housework); sometimes misdiagnosed as Chronic Fatigue Syndrome

* Migraine headaches, resulting from abnormal nervous system control of

blood flow

As noted above, many people with MVP never exhibit any of the above

symptoms. The condition can be detected during a routine check-up with a

simple stethoscope. After the ventricle begins to contract, a clicking sound

can be heard - the sound of the abnormal valve fighting the pressure of the

left ventricle. The diagnosis can be confirmed with an echocardiogram or

cardiac echo; the echocardiogram can also determine the level of severity of

the prolapse and the degree of regurgitation.

Most patients can be monitored simply, with a follow-up checkup every few

years. Patients with pronounced regurgitation problems (blood leaking

backward) may be monitored more closely.

What are the risks and problems associated with MVP?

Just as many MVP patients exhibit no symptoms, very few patients ever

experience any complications arising from this syndrome. Rare complications

include chest pain (angina pectoris) and irregular heart beat (arrhythmia),

both of which can be treated with medication, usually a beta-blocker.

Another rare complication involves formation of blood clots on the valve,

making an MVP patient vulnerable to strokes; this problem requires treatment

with an anticoagulant (blood thinner) medication.

The most common and serious MVP-related problem, endocarditis, involves

bacterial infection of the mitral valve. Although it can be fatal if left

untreated, endocarditis can be easily prevented. MVP patients are most

commonly vulnerable to introduction of bacteria into the bloodstream (and

endocarditis) when they are undergoing certain medical procedures,

particularly dental work or minor surgery. Because of this, patients should

inform their doctor or dentist that they have MVP, and be given antibiotic

prophylaxis (preventative treatment) before the procedure.

When does a patient require antibiotics?

The American Heart Association has recently updated its recommendations for

surgical and dental treatments in patients who have MVP and other heart

disorders. The use of antibiotics is important for preventing bacterial

endocarditis, a rare but potentially fatal infection that causes

inflammation of the heart's valves, or its inner lining. The use of

antibiotics for individuals who have MVP has been somewhat controversial.

The new guidelines suggest that for many procedures, most MVP patients do

not need antibiotics; antibiotics are only required for those individuals

who have valve leakage (mitral regurgitation) either detected as a heart

murmur or through an ultrasound, or people with greatly thickened valve

tissues. For a summary of the 1997 guidelines, see HeartInfo article:

Updated Guidelines for Use of Antibiotics To Prevent Bacterial Endocarditis.

The rare exception

Although most MVP patients do very well with the treatments and preventive

measures outlined above, there is sometimes need for heart surgery to either

repair or replace the mitral valve. This occurs only among patients who

experience severe mitral regurgitation, which can result in progressive

heart enlargement, and ultimately, heart failure.

Surgeons are more likely to perform corrective surgery rather than replace

the valve with an artificial one, mainly because the introduction of an

artificial valve requires lifelong use of blood thinners to prevent

clotting. If a patient is found to have regurgitation problems, surgery is

recommended and performed at as young an age as possible, reducing the risk

of further damage to the heart.

SOURCES:

" What is Mitral Valve Prolapse? " National Society for Mitral Valve Prolapse

and Dysautonomia; " Mitral Valve Prolapse, " American Heart Association;

" Mitral Valve Prolapse, " MedicineNet