realized in has material basis at all times has occurrent part aortic valve leaflet displacement into the left ventricle during left ventricular diastole degenerated structure in an aortic valve leaflet aortic valve prolapse disease_ontology MSH:D001023 UMLS_CUI:C0003505 A disease characterized by the displacement of a degenerated aortic valve leaflet into the left ventricle during diastole. DOID:5232 disease disease course