Echocardiographic detection of large left to right shunts and cardiomyopathies in infants and children.

Diagnostic separation of infants with signs of cardiac failure (hypoglycemia, sepsis, myocarditis, hypoxemia) but no congenital cardiocirculatory malformation from those with a large left to right shunt is crucial in newborn management. Echocardiographic studies of 218 infants and children allowed group separation and 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 end-systole (LA/Ao). In normal premature and full-term infants, Vcf (1.51 +/- 0.04 [mean +/- standard error]) was significantly lower than in infants with a large shunt (2.12 +/- 0.08, P less than 0.01) and higher than in infants with nonstructural heart disease (1.18 +/- 0.06, P less than 0.001). LA/Ao ratios were comparable in the groups with a large shunt and nonstructural heart disease (1.14 +/- 0.1 and 1.26 +/- 0.2, respectively) and were significantly higher in both groups than in normal subjects (0.77 +/- 0.01, P less than 0.001). Similar echocardiographic distinctions could be made when 10 older children (aged 2 to 10 years) with cardiomyopathy were compared with 45 normal older children. Serial determination of these variables was of major assistance in patient management.