Mitral Valve Prolapse
The mitral valve controls blood flow between the upper (atrium) and lower (ventricle) chambers on the left side of the heart. Normally, blood should flow in only one direction. This direction of blood flow is controlled by two leaflets.
Valve Leaflets Do Not Close Tightly or Evenly Enough
In mitral valve prolapse (MVP), your mitral valve leaflets do not close or fasten together on one plane, so that blood leaks to the receiving chamber. This may be because the supporting strands of one or both of the valve's leaflets are too long or because they are not attached tightly enough.
In some people with MVP, the valves may be abnormal in both ways -- the leaflets may be both enlarged and floppy. When the heart contracts, one or both of the leaflets cannot close tightly or evenly enough. Instead, part of one or both leaflets collapses backwards into the left atrium.
This condition affects an estimated 2 percent of adults in the United States.