Mitral Regurgitation

Definition

Mitral regurgitation (also called mitral valve insufficiency) is a common condition affecting the mitral valve, which is the valve that regulates the flow of blood from the lungs back into the heart. This valve is located between the atrium (upper chamber) and the ventricle (lower pumping chamber) of the left side of the heart. Blood must flow from the lungs to the atrium, through the mitral valve, and into the ventricle before being pumped out into the rest of the body. The mitral valve is composed of two leaflets which come together whenever the heart beats to prevent blood from leaking back to the lungs. Mitral regurgitation, or leakage of blood back across the mitral valve, occurs whenever those two leaflets do not close properly.

Causes

Mitral regurgitation may be caused by either an abnormality of the mitral valve (degenerative mitral valve disease) or by weakness of the heart muscle that is not strong enough to adequately close the valve (functional mitral regurgitation). 

Degenerative mitral valve disease causing regurgitation is due to either the chords (string-like tethers that attach the mitral valve leaflets to the muscle of the heart) being too long or broken, or abnormalities of the leaflet tissue. Functional mitral regurgitation commonly occurs because of heart injury from a heart attack.

Less common causes of mitral regurgitation include infection, rheumatic heart disease, or a congenital birth defect of the heart.

Risk

High blood pressure can worsen an already leaking mitral valve. Also, mitral valve prolapse (a condition in which one leaflet of the mitral valve snaps back on the other) can progress to mitral regurgitation.

Symptoms

Symptoms may include:

• Difficulty breathing, especially during exercise or when lying flat
• Awakening short of breath in the middle of the night
• Fatigue
• Sensation of rapid or irregular heartbeat (palpitations)
• Cough with exertion or when lying flat
• Frequent respiratory infections

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. The doctor may be alerted to mitral regurgitation by the following:

• Abnormal heart sounds, such as a heart murmur or click
• Signs of fluid in the lungs
  

Tests may include:

• Chest x-ray
• Electrocardiogram (ECG, EKG)
• Cardiac ultrasound (echocardiogram)
• Transesophageal echocardiogram
• Cardiac catheterization
• Holter monitor

Treatment

If you have mild or moderate degrees of mitral regurgitation, your condition will need to be monitored, but may not need immediate treatment for symptoms associated with mitral regurgitation.

Medications

While medications unfortunately are not effective for treating the underlying mechanism of mitral regurgitation, they may be prescribed to treat specific symptoms associated with mitral regurgitation. These medications include:

• Drugs that remove extra water from the lungs (diuretics)
• Medications that lower blood pressure
• Blood-thinning drugs
• Drugs to control heart rhythm problems
  

Surgery
Common types of surgery for mitral regurgitation include:

• Mitral valve replacement - This is the surgical replacement of a defective heart valve. This surgery is usually delayed until symptoms are severe or the patient can no longer be helped by other procedures.
• Mitral valve repair – Using a combination of stitches on the valve, rings around the valve or other techniques, the surgeon tries to repair the valve using the patient’s own valve tissue.
  

Percutaneous transcatheter mitral valve repair
A new option for patients with mitral regurgitation is a device called the MitraClip. It involves using catheters to place one or more tiny metal clips on the leaking portions of the mitral valve, effectively creating a repair of mitral regurgitation without having to do open heart surgery.

Prevention

There are several things you can do to try to avoid some of the complications of mitral regurgitation:

• Get regular medical care.
• If your valve problem was caused by rheumatic fever, talk to your doctor about antibiotic treatment to prevent future episodes of rheumatic fever.
• Avoid caffeine, alcohol and drugs (like decongestants) that speed up your heart rate; these will only worsen your symptoms.
• Maintain a healthy weight.
• Follow your doctor’s recommendations for exercise.
• Ask your doctor about cutting back on salt; this may help decrease the pressure in your heart and improve your symptoms.
• Monitor your blood pressure, and inform your healthcare provider if you seem to be developing high blood pressure, which can worsen your symptoms.