What is Mitral Regurgitation?

The heart has four chambers, with heart valves that open and close to allow blood to flow from one chamber to the next. The mitral valve is the valve between two chambers: the left atrium and the left ventricle.

When the mitral valve's leaflets (or flaps) do not close properly, some blood flows backward through the valve. This is called mitral regurgitation. Over time, mitral regurgitation may lead to heart failure.

Types of Mitral Regurgitation

There are two types of mitral regurgitation:

  • Degenerative mitral regurgitation, also known as primary or organic mitral regurgitation, is usually caused by a defect in the mitral valve.
  • Functional mitral regurgitation, also known as secondary mitral regurgitation, results from problems in the left ventricle that force blood backward through the valve. This causes regurgitation in an otherwise normal mitral valve.

Consequences of Mitral Regurgitation

Mitral regurgitation places an extra burden on the heart and lungs. In some cases, patients may never develop symptoms. In other cases, patients may develop an enlarged left ventricle as the heart works harder to pump blood throughout the body. Patients with chronic mitral regurgitation may develop symptoms of heart failure, such as fatigue or inability to exercise; decrease in appetite; dry, hacking cough (often worse when lying down); shortness of breath, especially at night; fainting; weight gain from fluid retention; or accumulation of fluid (swelling) in feet, ankles and lungs.

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Normal Functioning Heart. Close-up of mitral valve. Mitral valve of heart afflicted with functional regurgitation. Mitral valve of heart afflicted with degenerative regurgitation.