Indicator-dilution curves in acyanotic congenital heart disease.

Dye dilution and cardiac catheterization technics were used to study 36 patients with a central left-to-right shunt due to patent ductus arteriosus, atrial septal defect or ventricular septal defect. The configuration of dilution curves following injection of dye into an antecubital vein was similar in all instances. Principal abnormalities of the curve were a prolongation of its disappearance slope and a relative reduction in the peak concentration of dye. Quantitatively expressed, these abnormalities could be correlated with the magnitude of the left-to-right shunt. Curves of normal contour were observed following surgical closure of the ductus arteriosus, and in patients with isolated pulmonary stenosis.