Dynamic exercise echocardiography in children with congenital heart disease affecting the left heart

Abstract

Thirty-five children (male 22, female 13) with congenital heart disease resulting in volume and pressure overload of the left ventricle were investigated echocardiographically during supine bicycle exercise. The children had to follow a test-protocol with increasing workload. Left ventricular function parameters were measured from M-mode-echocardiography, electrocardiography and phonocardiograms before, during and after exercise and were expressed as fractional shortening (FS), velocity of circumferential fiber shortening (VcF) and the frequency corrected parameters: FScorr. = FS × 100 HR and VcFcorr. = VcF ×100 HR (HR = heart rate). The data of this group of children under study were compared to those obtained from 140 healthy children examined under similar conditions. In children with pressure overload, values for fractional shortening, velocity of circumferential fiber shortening and the frequency corrected parameters were significantly higher than in normals throughout exercise testing. In some children with moderate to severe aortic stenosis or coarctation the frequency corrected parameters showed a decrease at higher exercise levels instead of an increase as seen in the majority of cases. In these cases cardiac output was increased by an abnormal rise in heart rate. This was considered as a diminished left ventricular reserve. After aortic valve replacement in two cases with aortic stenosis, parameters of left ventricular function were still elevated at rest and during exercise testing. In two children with hypertrophic cardiomyopathy the almost maximally elevated rest values did not change during exercise. In children with mild volume overload (small ventricular septal defect or aortic incompetence) the left ventricular function parameters were within the normal range or slightly below.