Mitral Valve Regurgitation

There are two forms of mitral valve regurgitation (MR): chronic and acute. Chronic mitral valve regurgitation develops slowly over several years. Acute MR develops suddenly.

Chronic mitral valve regurgitation

Chronic mitral valve regurgitation is caused by diseases or conditions that damage the mitral valve over time. The valve then allows blood to leak backward (regurgitate).

The mitral valve may become hard, or calcified, around 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, calcium may build up inside the annulus. This hardened mitral valve cannot close completely, and blood leaks backward (regurgitates) into the upper left Reference chamber of the heart Opens New Window Reference Opens New Window (atrium).

Examples of diseases or conditions that can cause mitral valve regurgitation include:

• Reference Mitral valve prolapse Opens New Window.
• Heart defects or abnormalities present at birth (Reference congenital heart defects Opens New Window).
• Reference Endocarditis Opens New Window, which is an infection of the lining of the heart and heart valves. This infection can scar the mitral valve.
• Injury to the heart or the chordae tendineae, which are strong, flexible cords that control the opening and closing of the mitral valve.
• Dilation of the Reference left ventricle Opens New Window, or Reference heart failure Opens New Window. This can be caused by years of Reference high blood pressure Opens New Window, Reference coronary artery disease Opens New Window, or heart muscle disease (Reference cardiomyopathy).
• Autoimmune diseases that can damage the mitral valves, such as Reference rheumatoid arthritis Opens New Window or Reference lupus Opens New Window.
• Reference Marfan's syndrome Opens New Window, which is a connective tissue disease.
• Severe kidney disease.
• Reference Rheumatic fever Opens New Window, which can scar the heart valves and prevent them from closing completely.
• Previous use of the weight-loss medicine fen-phen (phentermine and fenfluramine/dexfenfluramine), which appears to increase the risk of heart valve disease.

Acute mitral valve regurgitation

Acute mitral valve regurgitation occurs when the mitral valve or one of its supporting structures ruptures suddenly, creating an immediate overload of blood volume and pressure in the left side of the heart. Your heart doesn't have time to adjust to the increased volume and pressure of blood (as it does in chronic MR).

Causes of sudden rupture include:

• Injury to the chordae tendineae. Endocarditis may also cause the chordae tendineae to rupture.
• Injury to the chest.
• Reference Heart attack, Opens New Window which may cause the rupture of the muscle (papillary) surrounding the valve.
• Problems with a Reference prosthetic Opens New Window mitral valve.
• Perforation of the mitral valve flap (leaflet), caused by endocarditis.

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