The arterial pressure pulse in muscular subaortic stenosis.

Brock (1957, 1959) using the term "Functional obstruction of the left ventricle" was the first to describe muscular subaortic stenosis. Since then, a number of reports (Bercu et al., 1958; Morrow and Braunwald, 1959; Brent et a!., 1960; Goodwin et al., 1960; Braunwald et al., 1960; Brachfeld and Gorlin, 1959, 1961; Pare et al., 1961; Boiteau and Allenstein, 1961) have appeared concerning this condition, the majority of which have noted the characteristic arterial pulse contour described by Brachfeld and Gorlin (1959). The latter authors (1959) and Goodwin et al. (1960) drew attention to the fast rising, early peaked arterial pulse pressure in muscular subaortic stenosis, which contrasted with the anacrotic slow rising pulse seen in valvular aortic stenosis. There appeared, however, to be a conflict of opinion concerning the arterial pulse contour in discrete, fixed subaortic stenosis. Thus, Brachfeld and Gorlin (1959) stated "a tight fibrous subaortic ring unassociated with muscular hypertrophy could theoretically be associated with an anacrotic shoulder. The relative rarity of such a lesion, however, makes the presence of marked anacrotism probably incompatible with a diagnosis of subaortic stenosis." Hancock (1961), on the other hand, described an anacrotic pulse in a case of membranous subaortic stenosis proven at operation and contrasted this pulse contour with that seen in muscular and fibromuscular subaortic stenosis, where the pulse contour was fast rising with an early peak systolic pressure. Kjellberg et al. (1959) and Brock and Fleming (1956) have also reported an anacrotic pulse in discrete subaortic stenosis. Because there was this difference of opinion and because of the importance in differentiating the muscular from the discrete fixed varieties of aortic stenosis, a detailed comparison was made of the arterial pulse contour in these groups. It is the purpose of this report to show that there were distinctive differences in the arterial pulse contour in muscular subaortic stenosis when compared with either valvular or discrete subvalvular aortic stenosis.