cardiovascular disorders
Aortic Stenosis
Introduction
Aortic stenosis (AS) is narrowing of the aortic valve, obstructing blood flow from the left ventricle to the ascending aorta during systole. Causes include a congenital bicuspid valve, idiopathic degenerative sclerosis with calcification, and rheumatic fever. Untreated AS progresses to become symptomatic with one or more of the classic triad of syncope, angina, and exertional dyspnea; heart failure and arrhythmias may develop. A crescendo-decrescendo ejection murmur is characteristic. Diagnosis is by physical examination and echocardiography. Asymptomatic AS in adults usually requires no treatment. Once symptoms develop, surgical or percutaneous valve replacement is required. For severe or symptomatic AS in children, balloon valvotomy is effective. (See also Overview of Cardiac Valvular Disorders .) 