Muscular Subaortic Stenosis

Abstract

A quarter of a century has passed since Brock's original report¹ of the condition characterized by asymmetric septal hypertrophy and a subaortic pressure gradient (muscular subaortic stenosis).² The pressure gradient may be affected by changes in myocardial contractility, systemic vascular resistance, and ventricular volume.³ Propranolol has little effect on the pressure gradient at rest, but it may diminish the increment that occurs with exercise.⁴ Verapamil has a greater effect than propranolol in reducing the gradient at rest, although substantial gradients (>50 mm Hg) have persisted even after high doses of intravenous verapamil, and in one patient the gradient markedly increased. . . .