Mitral regurgitation; chronic

Alternative names:

chronic mitral valve regurgitation

Definition:

A progressive or long-term disorder where the mitral heart valve does not close properly, causing blood to leak (backflow) into the left atrium from the left ventricle during systole (heart contraction).

Causes, incidence, and risk factors:

Regurgitation (leaking from insufficient valve closure) is caused by any disorder that weakens or damages the valve. Insufficient closure of the mitral valve causes blood to backflow to the left atrium. The blood flow to the body (cardiac output) is decreased because of the backflow. The heart may pump harder to try to compensate for the decreased blood flow to the body.

About 5% of individuals have mitral valve prolapse, involving weakening and ballooning out of the valve, which is a common cause of mitral regurgitation. Rheumatic heart disease causes thickening, rigidity, and retraction of the mitral valve leaflets and accounts for about one-third of all mitral regurgitation. Chronic mitral regurgitation may be inherited or caused by disorders such as atherosclerosis, hypertension (high blood pressure), left ventricle enlargement, connective tissue disorders such as Marfan's syndrome, other congenital defects, endocarditis, cardiac tumors, untreated syphilis, and others. Acute mitral regurgitation may become chronic.

Risk factors include an individual or family history of the above disorders. Mitral regurgitation affects approximately 6% of women and 3% of men. Congenital mitral regurgitation is rare.