1988 Volume 52 Issue 1 Pages 35-43
To determine whether low ejection fraction (EF) in mitral stenosis (MS) is the result of depressed contractility or is mediated by other factors, left ventricular (LV) function was analyzed by force-length and stress-shortening relationships. Thirty patients without heart disease served as normal controls (Group 1). Forty-three patients with MS were divided into 2 subgroups: Group 2 (n = 19) had EF within one standard deviation of the mean of Group 1, and Group 3 (n = 24) had EF (Group 2) was associated with low preload (end-diastolic stress) and low afterload (end-systolic stress), and preload and afterload were in the normal range in patients with low EF (Group 3). A significant negative correlation was observed in the whole group of patients with MS between EF and end-systolic stress (Y = -0.14X + 72.8, r = -0.61, p < 0.001), and a positive correlation between end-systolic stress and volume (Y = 1.39X + 65.4, r = 0.45, p < 0.01). These observations suggest that systolic shortening and end-systolic volume of the left ventricle are in part governed by afterload in this disease. It is concluded that low EF of MS is not mediated by reduced preload or inappropriately elevated afterload, and contractility of the ventricle is mildly depressed in MS.
