The echocardiographic manifestations of discrete membranous subaortic stenosis are described in three cases. The diagnosis was confirmed by cardiac catheterization in all and at operation in two. The characteristic finding in these patients was abnormal movement of the aortic valve leaflets. The leaflets opened rapidly with the onset of systole, then exhibited abrupt premature closure shortly after ventricular ejection. The valve remained partially closed throughout the remainder of systole. This premature leaflet closure Is believed to be caused by obstruction to aortic valve flow produced by the band-like fibrous subaortic tissue. The valve leaflets also exhibited a gross fluttering motion possibly caused by a jet stream effect of the turbulent blood hitting the leaflets. In the two patients treated surgically, postoperative echograms continued to show premature leaflet closure but the degree of closure was decreased. The echocardlogram of one patient had the characteristic systolic anterior bulge of the mitral valve observed in muscular subaortic stenosis or idiopathic hypertrophic subaortic stenosis. Our data suggest that the following echocardiographic findings are suggestive if not specific for discrete subaortic stenosis: aortic valve closure early in systole, persistent valve closure throughout the remainder of systole, coarse fluttering of the leaflets, and absence of asymmetric septal hypertrophy.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine