CHILDREN WITH COMPENSATED AORTIC STENOSIS MAINTAIN ENHANCED EJECTION PERFORMANCE DURING EXERCISE

Abstract

It has been shown that ejection phase indices are elevated in children with aortic stenosis (AS) at rest. We performed two-dimensional and M-mode echocardiography in 14 patients with AS and in 7 normal (NL) children at rest in the upright position, and at 50% and 752 of predicted maximal workload (PMW) during upright bicycle exercise. The two groups were compared by student's t tests and were not significantly different at the .05 level with respect to ht., wt., BSA, race and sex. There were no significant differences between the two groups in heart rate, % MVO2, or cardiac index. We also found no difference in LV diastolic dimension between the two groups at rest, at 50% and at 75% PMW. LV systolic dimension was significantly smaller at all levels in AS. LV systolic wall thickness was increased in AS. Rate corrected velocity of fiber shortening (VCFc) was significantly higher at rest in patients with AS, and remained so at both levels of exercise. The stepwise increase in VCFc was significant in both NL and AS from rest to 50%, and from 50% to 75% PMW; however, the incremental increase in VCFc from rest to exercise was not significantly different between the two groups. We conclude that patients with AS maintain enhanced ejection performance at 50% and 75% of PMW as evidenced by increased VCFc. A failure to increase VCFc during exercise in patients with aortic stenosis may imply decompensation and improve timing of surgical intervention.