DefinitionMitral valve prolapse is a heart problem in which the valve that separates the upper and lower chambers of the left side of the heart does not close properly.Alternative NamesBarlow syndrome; Floppy mitral valve; Myxomatous mitral valve; Billowing mitral valve; Systolic click-murmur syndrome; Prolapsing mitral leaflet syndromeCauses, incidence, and risk factorsThe mitral valve helps blood on the left side of the heart flow in one direction. It closes to keep blood from moving backwards when the heart beats (contracts).Mitral valve prolapse is the term used when the valve does not close properly. It can be caused by many different things. In most cases, it is harmless and patients usually do not know they have the problem. As much as 10% of the population has some minor, insignifi