Mitral Valve Regurgitation - Cause
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
There are two types of chronic mitral valve regurgitation: primary and secondary.
Primary means there is a problem with the anatomy of the valve. The valve does not work well and does not close tightly.
Primary regurgitation can be caused by:
- Calcium buildup as a person ages. 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 chamber of the heart (atrium).
- Mitral valve prolapse.
- Heart defects or
abnormalities present at birth (congenital heart defects).
- Endocarditis, which is an infection of
the lining of the heart and heart valves. This infection can scar the mitral
- Autoimmune diseases that
can damage the mitral valve, such as
rheumatoid arthritis or
- Marfan's syndrome, which is a connective tissue
- Rheumatic fever, which can scar the heart valves. This can 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.
- Injury to the heart or the chordae tendineae, which are
strong, flexible cords that control the opening and closing of the mitral
Secondary means another heart problem is causing the valve to not close tightly. The anatomy of the valve is typically normal. The heart problem affects the heart muscle, and this causes regurgitation.
Secondary regurgitation can be caused by heart problems that affect the left ventricle. These problems include:
Acute mitral valve regurgitation
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.
- Heart attack,
which may cause the rupture of the muscle (papillary) surrounding the valve.
- Problems with a
prosthetic mitral valve.
- Perforation of
the mitral valve flap (leaflet), caused by endocarditis.