Echo Distinction of Left-To-Right Shunts from Non-Structural Heart Disease (NHD) in Infancy

Abstract

Diagnostic separation of infants with NHD and signs of cardiac failure (hypoglycemia, sepsis, myocarditis, hypoxemia) from those with large L-R shunts (PDA, VSD) is crucial in newborn management. Echocardiographic studies of 200 infants allowed the separation of these two groups and their distinction from normal by the assessment of mean velocity of circumferential fiber shortening (VCF) and the ratio of left atrial to aortic root diameter at the end systole (LA/Ao). In normal premature and full-term infants VCF averaged 1.51± 0.04 (SE), this value was significantly higher in the large shunt group (2.12 ± 0.081, P< 0.001) and lower in the NHD infants (1.18 ± o.06, P< 0.001). LA/Ao ratios were comparable in the large shunt and NHD groups (1.14 ± 0.1 and 1.26 ± 0.2 respectively) and both were significantly higher than in normals (0.77 ± 0.01, P<0.001). No significant VCF or LA/Ao differences from normal were observed in infants with small L-R shunts. These reproducible echo indices provide a means for solving difficult and important problems in differential diagnosis. Since appropriate directional changes in these indices accompanied medical or surgical therapy, their determination was of major assistance in patient management.