Circulation, Vol 63, 254-263, Copyright © 1981 by American Heart Association
JT Whitmer, FW James, S Kaplan, DC Schwartz and MJ Knight
Twenty-three children with valvar or discrete subvalvar aortic stenosis
underwent a controlled, progressive bicycle exercise test within 6 months
before and 3-30 months after surgery for left ventricular outflow tract
obstruction. The patients were divided into three groups according to the
preoperative resting gradient of left ventricular to aortic peak systolic
pressure: 30-69 mm Hg (group A), 70-99 mm Hg (group B), and greater than or
equal to 100 mm Hg (group C). Preoperatively, 19 of 23 patients (83%)
developed significant ST depression (greater than or equal to 1.0 mm)
during exercise, whereas only seven (30%) had abnormal ST depression at
rest. Postoperatively, mean exercise-induced ST depression regressed to
less than 1 mm in all three groups. In the total population the frequency
of ST depression greater than 1 mm was significantly reduced after surgical
treatment and mean total work and peak exercise systolic blood pressure
were significantly increased within 12 months after surgery. Total work
increased significantly in group B within 12 months and in group C within
13-24 months after surgery, but remained unchanged on group A. Peak
exercise heart rates were similar before and after surgery in each group.
Peak exercise systolic pressures increased after surgery in all three
groups, but the mean differences were statistically significant only in
group C patients tested 13-24 months after surgery. The results of this
study show that exercise testing is useful for quantifying the severity of
aortic stenosis and documenting the clinical improvement (or lack thereof)
after surgical treatment, and that properly supervised exercise testing can
be performed at minimal risk to children with significant aortic stenosis.
ARTICLES
Exercise testing in children before and after surgical treatment of aortic stenosis
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