Chronic mitral regurgitation is a long-term disorder in which the heart's mitral valve does not close properly, causing blood to flow backward (leak) into the upper heart chamber when the left lower heart chamber contracts. The condition is progressive, which means it gradually gets worse.

See also: Acute mitral regurgitation

Mitral regurgitation is the most common type of heart valve insufficiency. 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 lower chamber of the heart (ventricle) to become widened may lead to mitral regurgitation. Over time, more blood backs up into the left upper chamber of the heart (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.

Mitral valve prolapse 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.

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:

• Atherosclerosis
• Endocarditis
• Heart tumors
• High blood pressure
• Marfan syndrome
• Swelling of the left lower heart chamber
• 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 banned by the FDA) for 4 or more months.

There are often no symptoms. When symptoms occur, they often develop gradually, and may include:

• Cough
• Fatigue, exhaustion, and light-headedness
• Palpitations (related to atrial fibrillation)
• Shortness of breath during activity and when lying down
• Urination, excessive at night

The doctor may detect a thrill (vibration) over the heart when feeling the chest area. An extra heart sound (S4 gallop) and a distinctive heart murmur may be heard when listening to the chest with a stethoscope. However, some patients may not have this murmur. If fluid backs up into the lungs, there may be crackles heard in the lungs.

The physical exam may also reveal ankle swelling, enlarged liver, distended neck veins, and other signs consistent with right-sided heart failure.

The following tests may be done:

• Cardiac color-Doppler study
• Cardiac catheterization
• Chest x-ray
• CT scan of the chest
• ECG
• Echocardiogram (an ultrasound examination of the heart)
• Magnetic resonance imaging (MRI)
• Radionuclide scans
• Transesophageal echocardiogram (TEE)

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.

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

Call your health care provider if you have symptoms of mitral valve regurgitation, or if symptoms worsen or do not improve with treatment.

Also call your health care provider if you are being treated for this condition and develop signs of infection, which include:

• Chills
• Fever
• General ill feeling
• Headache
• Muscle aches

Treat strep infections promptly to prevent rheumatic fever. Prompt treatment of disorders that can cause mitral regurgitation reduces your risk.

Any invasive procedure, including dental work and cleaning, can introduce bacteria into your bloodstream. The bacteria can infect a damaged mitral valve, causing endocarditis. Always tell your health care provider and dentist if you have a history of heart valve disease or congenital heart disease before treatment. Taking antibiotics before dental or other invasive procedures may decrease your risk of endocarditis.