SPECTRUM OF EXERCISE RESPONSES IN CHILDREN WITH AORTIC STENOSIS

Abstract

Significant abnormalities in cardiovascular dynamics may occur during exercise (Ex) in patients (P) with aortic stenosis (AS). This study was designed to record systolic pressure (ESP), electrocardiogram (ECG) and working capacity (WC) during upright bicycle Ex in 50 preoperative P (ages 6 to 23 years) with valvar or discrete subvalvar AS. Ninety-six normal children (ages 5 to 21 years) were the controls (C). Resting aortic gradients (AG) in the P ranged up to 234 mmHg at cardiac catheterization. Mean (±standard error) Ex data were subdivided by BSA and/or sex. In M and F < 1.2M2, ESP were 115±4 in P and 133±4 in N, p < .01. WC's were 77±11 in P and 88±8 in N, p > .1. ESP was below resting value in 2 and increased up to 10 mmHg in 8 P with AG ≥ 60 mm Hg. A positive Ex ECG occurred in 15/17 (88%) P with AG ≥ 60, 16/30 (53%) with AG of 10 to 59, 0/3 with AG < 10 and 7/96 (7%) N. ST depression (ST ↓) occurred in 16/30 P with normal resting ECG and 15/20 with left ventricular hypertrophy. We concluded that increased frequency of ST ↓, decreased ESP and WC are typical changes which may reflect severity or progression of AS in children.