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.

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.

• 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.

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

The choice of treatment depends on the symptoms present and the condition and function of the heart.

Antibiotics are prescribed if you have a bacteria infection. They are also used to reduce the risk of infective endocarditis in patients with mitral valve prolapse who are having dental work.

Anti-hypertensive drugs and vasodilators may be given to reduce the strain on the heart and may help improve the condition.  

Anti-coagulant or anti-platelet medications (blood thinners) may be used to prevent clot formation in patients with atrial fibrillation.

Digitalis may be used to strengthen the heartbeat, along with diuretics (water pills) to remove excess fluid in the lungs.

A low-sodium diet may be helpful. Most individuals have no symptoms; but if a person develops symptoms, activity may be restricted.

Hospitalization may be required for diagnosis and treatment of severe symptoms. Surgical repair or replacement of the valve is recommended if heart function is poor, if symptoms are severe, or if the condition deteriorates. Once the diagnosis of mitral regurgitation is made, periodic follow-up by a specialist is needed to determine the appropriateness of surgery.

The outcome varies and depends on the underlying conditions. Usually the condition is benign, so no therapy or restriction is necessary. Symptoms can usually be controlled with medication. In severe cases, valve repair or valve replacement may be necessary.

• Endocarditis (infection of the heart valve)
• Heart failure
• Pulmonary emboli (blood clots in the lungs)
• Stroke
• Clots to other areas
• Arrhythmias (abnormal heart rhythms), including atrial fibrillation and lethal arrhythmias

Call your health care provider if symptoms suggest mitral regurgitation or if you have mitral regurgitation and your symptoms worsen or do not improve with treatment. Also call your health care provider if signs of infection occur during treatment: fever, chills, muscle aches, headache, malaise (general ill feeling).

Treat strep infections promptly to prevent rheumatic fever. Treat other causative disorders.

Note any history of heart valve disease or congenital heart disease before treatment by a health care provider or dentist. Any dental work, including cleaning, and any invasive procedure can introduce bacteria into the bloodstream. This bacteria can infect a damaged mitral valve, causing endocarditis. Preventive treatment with antibiotics given just before dental or other invasive procedures may decrease the risk of endocarditis.