Mitral stenosis

Definition

Mitral stenosis is a narrowing or blockage of the opening of the mitral valve, which separates the upper and lower chambers on the left side of the heart. This prevents proper blood flow from moving between the left atrium (upper chamber of the heart) and ventricle (lower chamber of the heart).

Alternative Names

Causes

Mitral stenosis is a heart valve disorder. In adults, symptoms usually develop between the ages of 20 and 50. In infants and children, symptoms may be present from birth (congenital).

In adults, mitral stenosis most commonly occurs in people who have had rheumatic fever. Since rheumatic fever rates are declining in the United States, the incidence of mitral stenosis is also decreasing. Only rarely do other disorders cause mitral stenosis in adults.

In children, congenital mitral stenosis is more often part of a group of heart deformities.

Mitral stenosis prevents the valve from opening properly and blocks the blood flow from the left atrium to the left ventricle. As the valve area becomes smaller, less blood flows forward to the body. The atrium swells as pressure builds up and blood may flow back into the lungs, resulting in pulmonary edema (fluid in the lung tissue).

Symptoms may begin with an episode of atrial fibrillation or may be triggered by pregnancy or other stress on the body such as infection (in the heart, lungs, etc.) or other cardiac disorders.

In children, mitral stenosis may run in families.

References

Otto CM, Bonow RO. Valvular heart disease. In: Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007: chap 62.