Mitral valve prolapse (MVP) is a common condition in which the
mitral valve between the left upper chamber (left atrium) and left lower
chamber (left ventricle) of the heart does not function properly. In most
people, mitral valve prolapse does not cause any symptoms, usually does not
cause any health problems, and does not require treatment.
In mitral valve prolapse, the valve flaps bulge (prolapse) upward
into the left atrium rather than closing smoothly as the heart contracts. In
rare cases, blood may leak backward through the prolapsed valve into the
atrium. This condition is called mitral valve regurgitation.