Mitral Valve Prolapse

What is mitral valve prolapse?

The mitral valve allows blood to flow from the left atrium to the left ventricle in the heart. Mitral valve prolapse (MVP) is the bulging (prolapse) of one or both of the mitral valve flaps (leaflets) into the left atrium when the heart contracts. When the flaps don’t close properly, blood leaks backward. This is called regurgitation. Regurgitation may cause a heart murmur, an abnormal sound in the heart caused by turbulent blood flow. When regurgitation is present, it’s generally mild. But it can get worse over time.

The mitral valve is located between the left atrium and the left ventricle and has 2 flaps. Normally the flaps are tightly closed by small tendon or “cords” that connect the flaps to the muscles of the heart. This closure prevents blood from flowing backwards. In MVP, the flaps enlarge and stretch inward toward the left atrium, sometimes “snapping” during heart contraction. This may allow some back-flow or regurgitation of blood into the left atrium.

MVP usually does not need to be treated because it is rarely a serious condition, and it doesn’t damage the heart. However, regular checkups with a doctor are advised. 

What causes MVP?

The cause of MVP is unknown, but
most cases are thought to be inherited. There are 2 forms of MVP: primary and
secondary.

Primary MVP

Primary MVP means the mitral
valve is abnormal because of one or more of these changes:

  • One or both of the flaps are too
    large and thick
  • The flap surfaces are scarred
  • The tendon cords are thinner or
    longer than they should be
  • There are fibrin deposits on the
    flaps

Primary MVP is most often an
isolated disease. But is can be linked to other valve or skeletal problems. Some rare
instances of MVP are hereditary.

Secondary MVP

In secondary MVP, another
disease is linked to MVP. Often the valve flaps are not thickened. Prolapse occurs
for other reasons. The prolapse may be from:

  • Damage caused by decreased blood
    flow from coronary artery disease to the muscles attached to the tendon cords
  • Functional changes in the heart
    muscle
  • Damage to valve structures caused
    by heart attack, rheumatic heart disease, valve infection, or hypertrophic
    cardiomyopathy. Hypertrophic cardiomyopathy is when the left ventricle of the
    heart is larger than normal.
  • Damage caused by a connective tissue disorder such as Marfan
    syndrome

Who is at risk for MVP?

MVP affects both sexes and people
of all ages. Factors that may increase the risk of MVP include:

  • Graves disease (a condition that
    affects the thyroid gland)
  • Certain connective tissue disorders,
    such as Marfan syndrome
  • Scoliosis and other skeletal
    problems
  • Some types of muscular dystrophy

What are the symptoms of MVP?

MVP may not cause any symptoms.
Symptoms may vary depending on the degree of prolapse present. The presence of symptoms
doesn’t necessarily match the severity of MVP.

These are the most common symptoms
of MVP:

  • Fast or irregular heartbeats
    (palpitations).
    This may be the result of irregular heartbeats or just the
    sensation of the valve closing when the heart rhythm is normal.
  • Chest pain. Chest pain linked to MVP
    is different from chest pain associated with coronary artery disease. Usually the
    chest pain is not like classic angina, such as pain with exertion, but it can happen
    often, can be very uncomfortable, and can affect your quality of life.
  • Anxiety
  • Hyperventilation
  • Exercise intolerance
  • Dizziness

Depending on the severity of the
mitral regurgitation or leak, the left atrium or left ventricle may become enlarged,
leading to symptoms of heart failure. These symptoms include weakness, tiredness,
dizziness, and shortness of breath.

The symptoms of mitral valve
prolapse may look like other medical conditions or problems. Always see a healthcare
provider for a diagnosis.

How is mitral valve prolapse diagnosed?

You may have no noticeable
symptoms. Your doctor may  hear a click or murmur during a routine physical exam. The
“click” is created by the stretched flaps snapping against each other during
contraction. The murmur is caused by the blood leaking back into the left atrium. This
may be the only sign of MVP.

Along with a complete medical
history and physical exam, your provider may order these tests to diagnose MVP:

  • Electrocardiogram
    (ECG). This test records the strength
    and timing of the electrical activity of the heart. It shows abnormal rhythms and can
    sometimes detect heart muscle damage. Small sensors are taped to your skin to pick up
    the electrical activity.
  • Chest X-ray. An X-ray may be done to
    check your lungs and see if your heart is enlarged.
  • Transthoracic echocardiogram (echo or
    TTE).
    This is a noninvasive test that uses sound waves to evaluate the heart’s
    chambers and valves. The echo sound waves create an image on the monitor as an
    ultrasound transducer is passed over your chest above the heart. Echocardiography is
    the most useful diagnostic test for MVP. 

For more severe symptoms, other
tests may be done. These may include:

  • Stress test. This is also called
    treadmill or exercise ECG. ECG is done while you walk on a treadmill to monitor the
    heart during exercise. Breathing and blood pressure rates are also checked.
  • Cardiac catheterization. With this
    procedure, X-rays are taken after a contrast agent (dye) is injected into an artery
    to look for any narrowing, blockages, or other changes in certain arteries. The
    function of the heart and the valves may be checked, too.
  • Cardiac MRI. This is an imaging test
    that takes detailed pictures of the heart. It may be used to get a more precise look
    at the heart valves and heart muscle, or to prepare for heart valve surgery.


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