Mitral valve prolapse (MVP) occurs when the valve between your heart's left upper chamber (left atrium) and the left lower chamber (left ventricle) doesn't close properly.
During mitral valve prolapse, the leaflets of the mitral valve bulge (prolapse) upward or back into the left atrium as the heart contracts.
Mitral (MY-trul) valve prolapse sometimes leads to blood leaking backward into the left atrium, a condition called mitral valve regurgitation.
In most people, mitral valve prolapse isn't life-threatening and doesn't require treatment or changes in lifestyle. Some people with mitral valve prolapse, however, require treatment.