General
The normal Aortic valve consists of three semilunar cusps ( tri-cuspid).  Aortic Stenosis can be defined as obstruction of blood flow through the aortic valve. This is most usually caused by degenerative calcific changes of the valve in the elderly. However, it may also be caused by congenital unicuspid or bicuspid valve, or rheumatic fever. Except for perhaps Mitral Valve Prolapse, Aortic Stenosis is probably the most common of all valve lesions. The prognosis of Aortic Stenosis is usually good, but can quickly become critical in the later stage of the development. Valve replacement may then be necessary. Symptoms develop relatively late and no specific treatment is required while it remains asymptomatic. Vigorous exertion could lead to ventricular arrhythmias. Antibiotic prophylaxis against infective endocarditis is considered essential, even in asymptomatic patients.