Wilfred G. Bigelow

Results of ventriculomyotomy in muscular subaortic stenosis.

Abstract The results of surgery in 4 cases of muscular subaortic stenosis are described. An incision through the center or the anterior extremity of the abnormal muscle mass in the ventricular septum with blunt separation of the cut edges, was performed under direct vision using cardiac bypass. The obstruction to left ventricular outflow was abolished in all 4 cases, and marked symptomatic and hemodynamic improvement was noted in 3. Following surgery, the contour of the aortic pressure pulse was altered in that the tidal wave became greater than the previously dominant percussion wave. The altered physical findings reflected both the relief of the obstruction to left ventricular outflow and the improvement in the filling characteristics of the left ventricle. The fourth patient has had a prolonged postoperative illness, and final clinical improvement cannot be assessed. The postoperative electrocardiograms revealed left bundle branch block when the center of the ventricular septum was incised. When the anterior extremity of the septum was incised, the postoperative electrocardiograms revealed either left ventricular parietal block or anterolateral peri-infarction block. The results of this operative procedure appear promising and worthwhile pursuing in significantly disabled patients with muscular subaortic stenosis.