In mitral valve disease, the mitral valve, which is located between your left heart chambers (left atrium and left ventricle), doesn't work properly.
Types of mitral valve disease include:
Mitral valve regurgitation
In this condition, the flaps (leaflets) of the mitral valve don't close tightly, causing blood to leak backward into the left atrium of your heart. If not treated, it can result in heart muscle damage.
This condition is commonly caused by mitral valve prolapse, in which the leaflets bulge back into the left atrium as your heart contracts.
Mitral valve stenosis
In this condition, the flaps of the mitral valve become thick or stiff, and they may fuse together. This results in a narrowed valve opening and reduced blood flow from the left atrium to the left ventricle.
Treatment for mitral valve disease depends on the severity of your condition and whether your condition is becoming worse. Your doctor may eventually recommend that you have surgery to repair or replace your mitral valve.
Mitral valve disease care at Mayo Clinic