Mitral regurgitation is the leaking or backflow of blood through the valve between the left upper heart chamber (atrium) and the left lower chamber (ventricle). If serious, this can lead to a backup of blood in the left atrium and the lungs, causing enlargement and damage to the left ventricle and heart failure.
Mitral valve regurgitation can either be chronic or sudden (acute). Chronic MR develops slowly, possibly over decades and symptoms may never appear. Acute MR is a medical emergency.
Often no symptoms are present in chronic mitral regurgitation or symptoms may take decades to appear. Symptoms appear as the left ventricle expands to accomodate large amounts of blood flowing into the chamber. Symptoms include
- Shortness of breath with exertion and later may be short of breath at rest and in the night
- Cough, fatigue, swelling and excessive urination at night
- Lightheadedness, and heart palpitations may also be present
- In acute mitral regurgitation, symptoms develop quickly and include severe shortness of breath, coughing, chest pain, and rapid or irregular heartbeat.
The most common cause of chronic MR is mitral valve prolapse. Another cause includes hardening or calcification of the tough ring of tissue (annulus) to which the mitral valve flaps are attached. Normally the mitral annulus is soft and flexible, but as a person ages, it is not uncommon for calcium to deposit in the annulus. Other causes include congenital defects, endocarditis, injury to the heart, rheumatic fever, high blood pressure, previous use of weight loss medication (Fen-Phen), autoimmune diseases (rheumatoid arthritis, lupus, Marfans’s disease), and enlargement of the left ventricle. Acute mitral regurgitation may be the result of dysfunction or injury to the valve during a heart attack or infective endocarditis. These conditions may rupture the valve, the papillary muscle or chordae tendonae (structures that anchor the valve cusps). After age 55, some degree of mitral regurgitation is found in nearly 20% of those who have an echocardiogram.
How it is Diagnosed:
A stethoscope may reveal a murmur. Palpation may note a thrill (vibration) over the heart. Crackles or abnormal lung sounds may be heart on lung examination. If heart failure is present, ankle swelling, an enlarged liver, and/or distended neck veins may be present. An enlarged atrium with a thickened or deformed mitral valve with regurgitation may be seen on echocardiogram, with a transesophageal echocardiogram (TEE), cardiac doppler study, magnetic resonance imaging (MRI), or with cardiac catheterization. A chest XRay may show an enlarged left atrium. An ECG may suggest enlargement of the atrium (upper chamber of the heart). Enlargement of the left ventricle (lower chamber) is also a frequent finding.
Treatment is based on symptoms. If you have mild to moderate chronic MR and no symptoms, your health care provider may only monitor your condition. Medications may be used to prevent complications.
- Blood pressure medications and vasodilators (usually ACE inhibitors) may be used to help the heart pump more effeciently, reduce the strain on the heart, and reduce regurgitation.
- Blood thinners may be used to prevent clot formation with with irregular heart rhythms such as atrial fibrillation and with chronic MR.
- Water pills may be used to remove excess fluid in the lungs.
- A low sodium diet may be helpful.
- If atrial fibrillation is present, beta blockers, calcium channel blockers, and/or antiarrhythmics may be used.
- If a person develops symptoms, activity may be restricted. Usually the condition is benign and no restriction is needed.
Severe and/or acute MR generally requires surgical valve repair or replacement; especially when the heart pump function is poor, symptoms are severe, or if the condition deteriorates. Repair is often preferred over replacement but the decision is made depending on the type of damage your have. Acute MR may require hospitalization to treat symptoms and diagnose.
When should I call my health care provider?
Call if you have shortness of breath, fatiuge, and/or swelling in your legs or feet (symptoms of heart failure). Call if you have symptoms of infection such as a fever. Call for irregular heartbeats, fainting episodes, palpitations, or decreased exercise tolerance. Call 911 if you believe you are having symptoms of a heart attack (including severe chest pain), symptoms of a stroke, or lose consciuosness.
What preventative measure can I take?
- Treat strep infections promptly to prevent rheumatic fever.