The mitral valve is on the left side of the heart. It allows blood to flow from the left upper chamber into the left lower chamber. When the valve is not working well, it may need to be replaced.

Healthy heart valves allow blood to flow one way. Diseased valves either leak and cause backflow, or narrow and restrict blood flow. The condition can be life threatening. Sometimes the valve can be repaired. Other times, it must be replaced.

Rheumatic fever, other infections, defects at birth, and wear and tear are the most common causes of mitral valve problems.