Mitral Regurgitation - Chronic

Pictures & Images

See all Pictures & Images

Overview, Causes, & Risk Factors

Mitral regurgitation is the most common type of heart valve insufficiency. Any disorder that weakens or damages this valve can prevent it from closuring properly, causing this type of leakage. Mitral regurgitation becomes chronic when the condition persists rather than occurring for only a short time period.

When the mitral valve fails to close properly, blood flows back to the left atrium from the left ventricle. The blood flow to the body (cardiac output) is decreased as a result, so the heart pumps harder to try to compensate.

Chronic mitral regurgitation affects approximately 6% of women and 3% of men, but after 55 years of age, some degree of mitral regurgitation is found in almost 20% of men and women who undergo echocardiograms. Congenital (present from birth) mitral regurgitation is rare if not part of a more complex heart defect or syndrome. Mitral valve prolapse, which involves weakening and ballooning out of the valve and affects about 5% of the population, is a relatively common cause of chronic mitral regurgitation.

About one-third of all cases of chronic mitral regurgitation are caused by rheumatic heart disease, a complication of untreated strep throat that is becoming less common. Rheumatic heart disease can lead to thickening, rigidity, and retraction of the mitral valve leaflets

Chronic mitral regurgitation can also be caused by disorders such as atherosclerosis, hypertension (high blood pressure), left ventricular enlargement, connective tissue disorders such as Marfan's syndrome, other congenital defects, endocarditis (infection of the heart valve), cardiac tumors, or untreated syphilis (rare). Acute mitral regurgitation may become chronic.

Risk factors include an individual or family history of any of the disorders mentioned above and use of fenfluramine or dexfenfluramine (appetite suppressants now banned by the FDA) for four months or longer.