Mitral valve replacement is done when the mitral valve is not working well. The mitral valve is on the left side of the heart. It allows blood to flow from the left upper chamber (left atrium) into the left lower chamber (left ventricle). When the valve is not working well, it may need to be replaced.

Healthy heart valves permit one-way flow of blood. Diseased valves either leak, causing back flow, or narrow, restricting flow. In either case, the condition can be life-threatening. Sometimes the valve can be repaired. At other times it must be replaced.

Rheumatic fever, infections, congenital defects (defects at birth), and degenerative disease (wear and tear) are the most common causes of mitral valve problems.