The Effects of Operation on the Echocardiographic Features of Idiopathic Hypertrophic Subaortic Stenosis
Simultaneous cardiac catheterizations and echocardiograms were performed before and 6-12 months following ventriculoseptomyectomy in 10 patients with idiopathic hypertrophic subaortic stenosis (IHSS) to define the effects of operation on the echocardiographic features of IHSS. Preoperatively, the resting peak systolic gradient ranged from 40-125 mm Hg and averaged 81 mm Hg. Postoperatively no gradient was present in nine patients and one patient had a 15 mm Hg residual gradient. Echocardiographic obstruction index averaged 54 msec/mm (range 35-85) preoperatively and was reduced to 12 msec/mm (0-67) postoperatively. The markedly abnormal systolic anterior motion (SAM) of the anterior mitral leaflet present in all preoperatively was diminished or absent following operation. The preoperative left ventricular outflow tract dimension, calculated by echocardiogram at peak SAM, averaged 1.4 mm (range 0-5) and increased to 15 mm (3-25) following operation. Ventricular septal width averaged 18 mm (range 14-21) and posterior wall thickness averaged 11 mm (range 7-13) and were unchanged following operation. Mitral valve diastolic closing velocity, measured echocardiographically was not altered by operation (average 35 mm/sec before and after operation), suggesting that significant changes in left ventricular compliance did not occur. The echocardiogram in patients after ventriculoseptomyectomy demonstrates more normal mitral valve motion and increased left ventricular outflow tract dimension. In some patients uneven mitral leaflet-septal contact may produce significantly abnormal areas of SAM without obstruction.
- Mitral valve motion
- Left ventricular outflow obstruction
- Hypertrophic obstructive cardiomyopathy
- Received March 5, 1974.
- Accepted July 5, 1974.
- © 1974 American Heart Association, Inc.