Mitral stenosis is best described as:

• A. A narrowed mitral valve that blocks blood flow from the left ventricle to the left atrium.
• B. A narrowed mitral valve that blocks blood flow from the left atrium to the left ventricle.
• C. A valve that leaks back into the left atrium.
• D. A narrowed mitral valve that blocks blood flow from the left atrium to the left ventricle, often due to infection, calcification, or genetics.

Answer: (D)

Mitral stenosis means the mitral valve opening is narrowed, so blood cannot flow easily from the left atrium into the left ventricle during diastole. The best description includes both this directional obstruction and common causes, such as rheumatic infection (the typical infectious cause), calcification, or congenital/genetic factors that can lead to a narrowed valve. This explains why the valve becomes constricted and how it fits with patient history, like prior rheumatic fever. The consequence is higher pressure in the left atrium and potential pulmonary congestion, which ties to the symptoms you’d expect. While simply stating the directional blockage is accurate, including etiologies makes the statement more complete and clinically relevant.