What is the significance of an obstructive lesion in the mitral valve?

Slow flow: Mitral stenosis, a narrowing of the mitral valve, stresses the heart making it have to work harder to pump the blood forward. If severe enough, the output of the heart may drop and cause symptoms such as fatigue or shortness of breath. Fortunately, rheumatic fever is now rare in the U.S. So we see much less mitral stenosis. Surgery can correct the problem.

Mitral valve: The mitral valve has to open properly to let blood flow into the left ventricle from the atrium. If it doesn't, we call this stenosis. It has to close to keep the blood flowing toward the body, if it does not; we call this regurgitation or insufficiency. Either or both problems can exist with the valve if its abnormal. Insufficiency is more common.