Quadricuspid aortic valve abnormal aortic valve cusp morphology quadricuspid aortic valve 2023-12-13T13:43:40Z four-leaflet aortic valve MPheno.ontology four-cusp aortic valve MP:0031538 QAV presence of four cusps (leaflets) of equal or varying sizes in the aortic valve instead of three quadricuspid aortic valve