Acute mitral regurgitation is a disorder in which the heart's mitral valve suddenly does not close properly, causing blood to flow backward (leak) into the upper heart chamber when the left lower heart chamber contracts.

See also: Chronic mitral regurgitation

Regurgitation means leaking from a valve that doesn't close all the way. Diseases that weaken or damage the valve or its supporting structures cause mitral regurgitation.

When the mitral valve doesn't close all the way, blood flows backward into the left 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.

Acute mitral regurgitation may be caused by dysfunction or injury to the valve following a heart attack or infection of the heart valve (infective endocarditis). These conditions may rupture the valve or surrounding structures, leaving an opening for blood to move backwards.

• Chest pain -- unrelated to coronary artery disease or a heart attack
• Cough
• Rapid breathing
• Shortness of breath that increases when lying flat (orthopnea)
• Sensation of feeling the heart beat (palpitations)

Note: Symptoms may start suddenly.

The doctor may detect a thrill (vibration) over the heart when feeling (palpating) 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.

Blood pressure is usually normal.

The following tests may be performed:

• Cardiac catheterization
• Chest MRI scan
• Chest x-ray - may also show fluid in the lungs or prominent lung veins
• Color flow Doppler exam
• CT scan of the chest
• Echocardiogram
• ECG - usually shows a normal sinus rhythm but may show abnormal heart rhythms
• Radionuclide scans
• Right heart catheterization - may show high left atrial pressure.
• Transesophageal echocardiogram (TEE)

Patients with severe symptoms may need to be admitted to a hospital for diagnosis and treatment.

Emergency surgery may be necessary for severe leakages, usually resulting from infection, heart attack, or rupture of a valve structure.

Medications may include:

• Antibiotics to fight any bacterial infections
• Antiarrhythmics to control heart rhythms
• Blood thinners to prevent clot formation if atrial fibrillation is present (mainly used for patients with chronic mitral regurgitation)
• Digitalis to strengthen the heartbeat
• Diuretics (water pills) to remove excess fluid in the lungs
• Vasodilators to dilate blood vessels and reduce the workload of the heart

If blood pressure cannot be controlled, an intra-aortic balloon pump (IABP) may be used to help move blood forward into the aorta, the main artery from the heart.

How well a patient does depends on the cause and severity of the valve leakage. Milder forms may become a chronic condition.

Acute mitral regurgitation can rarely be controlled with medications. Surgery is usually needed to repair or replace the mitral valve. See: Valve replacement.

Abnormal heart rhythms associated with acute mitral regurgitation can sometimes be deadly.

• Abnormal heart rhythms, including atrial fibrillation
• Blood clots in other parts of the body
• Chronic mitral regurgitation
• Heart failure
• Pulmonary edema (fluid in the lungs)
• Stroke
• Valve infection

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

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

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.