Dynamics of left ventricular emptying in hypertrophic subaortic stenosis: A cineangiographic and hemodynamic study

Abstract

1. 1. Left ventricular cineangiograms of 9 patients with “idiopathic hypertrophic subaortic stenosis” were studied with reference to rate and pattern of left ventricular contraction, and compared with similar studies of 11 normal subjects and 8 patients with valvular aortic stenosis. 2. 2. The ventricle in “idiopathic hypertrophic subaortic stenosis” emptied more completely and in less time than did the unobstructed normal ventricle. The left ventricle in valvular aortic stenosis emptied more completely than did the normal, but required a significantly longer time interval. 3. 3. Increased pressure gradients in the same IHSS patient after premature beats or after isoproterenol were associated with more rapid and complete ventricular emptying, rather than evidence of increased obstruction. 4. 4. In no case was significant narrowing of the left ventricular outflow tract seen in the RAO projection. Additional LAO views were obtained in 4 patients, and no narrowing was seen. There was no distinguishable difference in the pattern of subvalvular versus apical contraction between the three groups to suggest outflow tract obstruction in the “idiopathic hypertrophic subaortic stenosis” group—i.e., neither early subvalvular contraction nor delayed apical emptying were seen. 5. 5. These data provide evidence that the pressure gradient in “idiopathic hypertrophic subaortic stenosis” is not due to obstruction in those patients in whom obstruction is not clearly demonstrated by other means.