Mitral regurgitation - chronic Health Article

Definition

Chronic mitral regurgitation is a long-term disorder in which the valve (mitral valve) that separates the left upper chamber of the heart (atrium) from the left lower chamber (ventricle) does not close properly. The condition is progressive, which means it gradually gets worse.

Alternative Names

Chronic mitral valve regurgitation; Mitral valve insufficiency

Causes, incidence, and risk factors

Mitral regurgitation is the most common type of heart valve insufficiency. Chronic mitral regurgitation affects approximately 6% of women and 3% of men. After 55 years of age, some degree of mitral regurgitation is found in almost 20% of men and women who have an echocardiogram.

Any disorder that weakens or damages the mitral valve or causes the left ventricle to become widened (dilated) may lead to mitral regurgitation. Over time, more blood backs up into the left atrium from the left ventricle, and the heart has to work harder to pump blood to the rest of the body. This may lead to congestive heart failure.

Mitral regurgitation becomes chronic when the condition persists rather than occurring for only a short time period. Chronic mitral regurgitation should be distinguished from acute mitral regurgitation. Acute mitral regurgitation may become chronic.

Mitral valve prolapse, which involves weakening and ballooning out of the valve and affects about 5% of the population, is a relatively common cause of chronic mitral regurgitation.

About one-third of all cases of chronic mitral regurgitation are caused by rheumatic heart disease, a complication of untreated strep throat that is becoming less common. Rheumatic heart disease can lead to thickening, rigidity, and retraction of the mitral valve leaflets.

Congenital (present from birth) mitral regurgitation is rare if it is not part of a more complex heart defect or syndrome.

Chronic mitral regurgitation can also be caused by disorders such as atherosclerosis, hypertension (high blood pressure), left ventricular enlargement, connective tissue disorders such as Marfan's syndrome, other congenital defects, endocarditis (infection of the heart valve), cardiac tumors, or untreated syphilis (rare). Risk factors include an individual or family history of any of the disorders mentioned above and use of fenfluramine or dexfenfluramine (appetite suppressants now banned by the FDA) for four or more months.

Symptoms

• Fatigue, exhaustion, and light-headedness (may result from low cardiac output)
• Palpitations (related to atrial fibrillation)
• Cough
• Shortness of breath
  • Exertion (exertional dyspnea)
  • When lying down (orthopnea)
• Urination, excessive at night

Note: Often no symptoms are present. When symptoms occur, they often develop gradually.

Signs and tests

Palpation may show thrill (vibration) over the heart. A stethoscope examination of the heart reveals a distinctive murmur. Rales (a crackly sound) or other abnormal breath sounds may be heard on lung examination. Ankle swelling, enlarged liver, distended neck veins, and other signs consistent with right-sided heart failure may be present.

An enlarged left atrium with a thickened or deformed mitral valve, and regurgitation of blood may be seen on:

• Echocardiogram (an ultrasound examination of the heart)
• Transesophageal echocardiogram (TEE)
• Cardiac color-Doppler study
• Magnetic resonance imaging (MRI)
• Cardiac catheterization