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Mitral regurgitation - chronic

Definition

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

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. After age 55, some degree of mitral regurgitation is found in almost 20% of men and women who have an echocardiogram.

Blood that flows between different chambers of your heart must flow through a valve. The valve between the two chambers on the left side of your heart is called the mitral valve.

Regurgitation refers to leaking from a valve that doesn't close all the way. Diseases that weaken or damage the valve or the heart tissue around the valve cause mitral regurgitation.

When the mitral valve doesn't close all the way, blood flows backward into the upper heart chamber (atrium). This leads to a decrease in blood flow to the rest of the body. As a result, the heart may try to pump harder. This may lead to congestive heart failure.

Mitral regurgitation may begin suddenly, most often after a heart attack. When the regurgitation does not go away, it becomes chronic (long-term).

Mitral valve prolapse (MVP) is a relatively common cause of chronic mitral regurgitation. However, most patients with MVP do not develop severe mitral regurgitation.

One out of three 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 most often part of a more complex heart defect or syndrome.

Common causes of chronic mitral regurgitation include:

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.

Symptoms

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

Signs and tests

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)

Treatment

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

Patients with high blood pressure or a weakened heart muscle may be given medications to reduce the strain on the heart and help improve the condition.

Anticoagulant or antiplatelet medications (blood thinners) may be used to prevent clots from forming 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 people 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, symptoms are severe, or the condition gets worse. Once the diagnosis of mitral regurgitation is made, you should have regular follow-ups with a specialist to determine whether you need surgery.

In the past, patients with heart valve problems such as mitral regurgitation were given antibiotics before dental work or an invasive procedure, such as colonoscopy. The antibiotics were given to prevent an infection of the damaged heart valve. However, antibiotics are now used much less often before dental work and other procedures.

Expectations (prognosis)

The outcome varies based 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 needed.

Complications

Calling your health care provider

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

Prevention

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.

References

Karchmer AW. Infectious endocarditis. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007:chap 63.

Nishimura RA, Carabello BA, Faxon DP, et al. ACC/AHA 2008 Guideline update on valvular heart disease: focused update on infective endocarditis: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008;52:676-685.

Fullerton DA, Harken AH. Acquired heart disease: valvular. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Sunders Elsevier;2008:chap 62.


Review Date: 5/6/2010
Reviewed By: Issam Mikati, MD, Associate Professor of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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