Mitral valve regurgitation

Causes

Mitral regurgitation is the most common type of heart valve disorder.

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.

When the mitral valve doesn't close all the way, blood flows backward into the upper heart chamber (atrium) from the lower chamber as it contracts. 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 long-term (chronic).

Many other diseases or problems can weaken or damage the valve or the heart tissue around the valve and cause mitral regurgitation:

• Coronary heart disease and high blood pressure
• Infection of the heart valves
• Mitral valve prolapse (MVP)
• Rare causes, such as untreated syphilis or marfan syndrome
• Rheumatic heart disease, a complication of untreated strep throat (which is becoming less common because of effective treatment)
• Swelling of the left lower heart chamber

Risk factors include a personal 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

Symptoms may begin suddenly if:

• A heart attack damages the muscles around the mitral valve.
• The cords that attach the muscle to the valve break.
• An infection of the valve destroys part of the valve.

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

• Cough
• Fatigue, exhaustion, and light-headedness
• Rapid breathing
• Sensation of feeling the heart beat (palpitations) or a rapid heartbeat
• Shortness of breath that increases with activity and when lying down
• Urination, excessive at night

Exams and Tests

When listening to your heart and lungs, the health care provider may detect:

• A thrill (vibration) over the heart when feeling the chest area
• An extra heart sound (S4 gallop)
• A distinctive heart murmur
• Crackles in the lungs (if fluid backs up into the lungs)

The physical exam may also reveal ankle swelling, an enlarged liver, bulging neck veins, and other signs of right-sided heart failure.

The following tests may be done to examine the heart valve structure and function:

• CT scan of the chest
• Echocardiogram (an ultrasound examination of the heart)
• Magnetic resonance imaging (MRI)

Cardiac catheterization may be done if heart function becomes worse.

Treatment

The choice of treatment depends on the symptoms, 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.

The following drugs may be prescribed when mitral regurgitation symptoms get worse:

• Beta-blockers or ACE inhibitors
• Blood thinners (anticoagulants) to help prevent blood clots in people with atrial fibrillation
• Drugs that help control uneven or abnormal heartbeats
• Water pills (diuretics) to remove excess fluid in the lungs

A low-sodium diet may be helpful. If a person develops symptoms, activity may be restricted.

Once the diagnosis is made, you should make regular visits to your health care provider to follow your symptoms and heart function. Surgical repair or replacement of the valve is recommended if heart function is poor, the heart becomes larger (dilated), and symptoms become more severe.

People with abnormal or damaged heart valves are at risk for an infection called endocarditis. Anything that causes bacteria to get into your bloodstream can lead to this infection. Steps to avoid this problem include:

• Avoid unclean injections
• Treat strep infections quickly to prevent rheumatic fever
• Always tell your health care provider and dentist if you have a history of heart valve disease or congenital heart disease before treatment. Guidelines recommend antibiotics for some patients, but only under certain conditions.

Outlook (Prognosis)

The outcome varies. Usually the condition is mild, so no therapy or restriction is needed. Symptoms can usually be controlled with medication.

Possible Complications

Problems that may develop include:

• Abnormal heart rhythms, including atrial fibrillation and possibly more serious, or even life-threatening abnormal rhythms
• Clots that may travel to other areas of the body, such as the lungs or brain
• Infection of the heart valve
• Heart failure        

When to Contact a Medical Professional

Call your health care provider if symptoms get worse 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 right away to prevent rheumatic fever. Prompt treatment of disorders that can cause mitral regurgitation reduces your risk.

Alternative Names

Mitral valve regurgitation; Mitral valve insufficiency

References

Otto CM, Bonow RO. Valvular heart disease. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 66.

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.

Update Date: 6/4/2012

Updated by: Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.