_:vb50956817 . _:vb50956817 . _:vb50956817 "url:http://en.wikipedia.org/wiki/Mitral_valve_prolapse"^^ . _:vb50956817 . _:vb50956817 "url:http://ghr.nlm.nih.gov/glossary=mitralvalveprolapse"^^ . _:vb50956817 . _:vb50956817 "url:http://www.merckmanuals.com/professional/cardiovascular_disorders/valvular_disorders/mitral_valve_prolapse_mvp.html"^^ . _:vb50956817 . _:vb50956817 . _:vb50956817 . _:vb50956817 "url:https://www.rarediseases.org/rare-disease-information/rare-diseases/byID/564/viewAbstract"^^ . _:vb50956817 "A mitral valve disease where one or both of the cusps of the mitral valve bulge or collapse backward in the left atrium during systole."^^ .