Atrial right-to-left shunt in infants with respiratory and cardiac distress but without congenital heart disease. Demonstration by contrast echocardiography.

Contrast echocardiography was used to detect atrial right-to-left shunts in 20 term infants; there were 10 cyanosed infants who had severe respiratory distress and signs of cardiac failure but no apparent congenital heart disease and 10 noncyanosed infants with no respiratory distress and no signs of cardiac failure who underwent exchange transfusion for hyperbilirubinemia. All of the venous contrast echocardiograms in the cyanosed infants showed an atrial right-to-left shunt with a dense contrast effect in the left atrium and aorta but little in the right ventricle. A sparse effect in the left atrium and a dense one in the right ventricle were recorded in infants with resolving respiratory distress and in three infants from the control group. The other seven infants in the control group showed no right-to-left shunt. Conventional M-mode echocardiograms showed no evidence of congenital heart disease in any of the 20 infants. This contrast echocardiographic technique was useful for demonstrating an atrial right-to-left shunt in cyanosed term infants with neonatal respiratory problems and signs of congestive failure but no apparent congenital heart disease.