Congenitally abnormal aortic valve with only two functional valve cusps, usually due to fusion of two of the cusps. This is associated with valvular stenosis and/or insufficiency, as well as abnormalities of the aorta including aneurysms and coarctation. It may occur alone or with other cardiovascular abnormalities such as ventricular septal defect, patent ductus arteriosus, and sinus of Valsalva aneurysm.

Common signs and symptoms include chest pain, decreased exercise tolerance, dyspnea, heart murmur, palpitations, syncope, and aortic regurgitation, or patients may remain asymptomatic for a long time. Infective endocarditis, aortic dilation, and aortic dissection are serious complications. A life-threatening association with symptomatic aortic stenosis puts the patient at risk of sudden death.

Management is complex and involves a range of pharmacotherapies, surgical procedures, valve repairs, and valve replacements.