The mitral valve in the heart is between the left atrium (a chamber in the top part of the heart) and left ventricle (a chamber in the bottom part). It opens when the atrium pumps blood into the ventricle. It closes when the ventricle pumps blood out into the body. Closing prevents the blood from going back into the atrium. Blood leaking back into the atrium from the ventricle is called regurgitation (or insufficiency or incompetence). Blood isn’t pumped out of the heart properly, and the atrium cannot fill during the next cycle. Blood may back up in the right-sided system (to the lungs) and cause lungs to fill with fluid. The left ventricle then has to do more work to move blood. This extra work may later cause heart failure.
The cause is damage to the mitral valve. Damage may result from a congenital abnormality (present at birth) or a heart attack (or myocardial infarction, in which parts of the heart die because they don’t have enough blood). Other causes are infections such as rheumatic fever (from streptococcal infections such as strep throat), connective tissue disorders such as lupus, and inherited conditions such as Marfan syndrome. Mitral valve prolapse also can lead to mitral regurgitation.
People often live for years without knowing that they have this condition. People with a small defect have no symptoms. Symptoms developing after a few years usually include tiredness and difficulty breathing.
The health care provider diagnoses mitral regurgitation by listening to heart sounds. Abnormal blood movement makes a sound called a murmur. The health care provider hears the murmur through a stethoscope. The health care provider may also order sonography of the heart (echocardiography), chest x-rays, and electrocardiography (ECG) to confirm the diagnosis. The x-rays often show a large left atrium. Abnormal heart rhythms (arrhythmias such as atrial fibrillation) can occur and may cause palpitations, or irregular heartbeat.
For a mild condition, medicines are used to prevent complications. Surgery consisting of mitral valve replacement is done when regurgitation worsens and medicines don’t work to control symptoms.
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Copyright © 2016 by Saunders, an imprint of Elsevier, Inc.
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