Mitral regurgitation; acute

Causes and Risks:
Regurgitation (leaking from insufficient valve closure) is caused by disorders that weaken or damages the valve. Inadequate closure of the mitral valve causes blood to backflow to the left atrium. The blood flow to the rest of the body is decreased because of the backflow. The heart may pump harder to try to compensate for the decreased blood flow to the body.

Acute mitral regurgitation may be the result of dysfunction or injury to the valve following MI or infective endocarditis . These conditions may result in rupture of the valve, papillary muscle , or chordae tendineae (the structures that anchor the valve cusps). A rupture of these structures results in the valve leaflet prolapsing (protruding) into the atrium, leaving an opening for the backflow of blood.

Risk factors include an individual or family history of the above disorders.

Mitral regurgitation (both acute and chronic mitral regurgitation) affects approximately 5 out of 10,000 people.

Prevention:
Prompt treatment of causative disorders reduces the risk of mitral regurgitation. 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.

Symptoms:

Note: There may be an abrupt onset of symptoms.

Signs and Tests:
Palpation may show thrill (vibration) over the heart. A stethoscope may reveal a distinctive (holosystolic) murmur in the heart. If fluid backs up into the lungs, there may be crackles or other signs of congestion of the pulmonary (lung) veins. Blood pressure is usually normal. Billowing of the mitral valve and/or regurgitation of blood may show on:

A chest X-ray may also show fluid in the lungs or prominent pulmonary veins. Swan-Ganz ( left heart catheterization ) pressure readings will record a marked elevation of left atrial pressure. An ECG usually shows a normal sinus rhythm, but may show arrhythmias such as atrial fibrillation (atrial fibrillation is more common in chronic mitral regurgitation). Other tests may include a chest MRI scan , radionucleotide scans, or a CT scan of the chest .

Treatment:
Hospitalization may be required for diagnosis and treatment of severe symptoms. The goal of treatment is to control the symptoms. Emergency surgery is often necessary if acute regurgitation is a result of endocarditis , MI , or ruptured cordae.

Antibiotics may be prescribed if there is a bacterial infection. Antiarrhythmics may be needed to control irregular rhythms. Vasodilators reduce the workload of the heart. Digitalis may be used to strengthen heartbeat, and diuretics to remove excess fluid such as fluid in the lungs. Anticoagulants or antiplatelet medications may be used to prevent clot formation if atrial fibrillation is present (atrial fibrillation increases the chances of clot formation).

In emergency situations when blood pressure cannot be maintained, devices such as the intra-aortic balloon pump (IABP) reduce backflow by lowering resistance in the aorta.

Prognosis:
The outcome varies and depends on underlying conditions and the severity of the acute regurgitation. This disorder can sometimes be controlled with medications, but surgery is often necessary (see valve replacement ). It may become a chronic condition.

Complications:



Call Your Healthcare Provider:
Call your health care provider if symptoms indicate mitral valve regurgitation, or if symptoms worsen or do not improve with treatment. Call your health care provider if during treatment, signs of infection occur: fever , chills, muscle aches, headache, and malaise (general ill feeling).


This is a cross-sectional view of the interior of the heart. The valves, chambers, and associated vessels are labeled.