Assessment of site and severity in congenital aortic stenosis.

Abstract

Discrete subvalvar aortic stenosis is distinguished from non-calcific valvar aortic stenosis by the absence of an early systolic ejection click and by a soft or inaudible aortic valve closure sound. These auscultatory characteristics closely resemble those of calcific aortic valve stenosis and it was shown that immobility of the valve is the basis for its silence in each group. It is postulated that the poor valve movement in discrete subaortic stenosis is due to the pressure baffle imposed by the subvalvar obstruction. Persistence of the subvalvar obstruction in the relaxing ventricle is responsible both for the softness of aortic valve closure and for incompetence of the valve. It is suggested that the early diastolic murmur in such cases is started by blood refluxing through the valve and continued by the same blood refluxing through the subvalvar stenosis. In valvar aortic stenosis, as in mitral stenosis, loud aortic valve opening and closure sounds indicate that the cusps are mobile, and, as in mitral stenosis, the sounds disappear when the valve calcifies in later life. The most reliable criterion of severity in fixed aortic stenosis was found to be the position of the peak of the murmur in relation to its duration. A murmur with an early peak indicated mild stenosis regardless of its duration, whereas a delayed maximum intensity could be correlated with more severe obstruction.