What is the X in X-mas?
mitral stenosis n.
A narrowing of the mitral valve usually caused by rheumatic fever and resulting in an obstruction to the flow of blood from the left atrium to the left ventricle.
narrowing of the mitral valve, the function of which is to permit blood to flow from the atrium, or upper chamber, to the ventricle, or lower chamber, of the left side of the heart and to prevent its backflow. Narrowing of the mitral valve is usually a result of rheumatic fever; rarely, the narrowed valve is a congenital defect. The condition, most common in women under 45, is diagnosed by recognition of typical heart sounds and confirmed by certain patterns that appear in echocardiography or electrocardiography.