To characterize the changes in circulating catecholamine levels for children with varying degrees of congestive heart failure (CHF), plasma norepinephrine (NE) and epinephrine (E) levels were measured, using high performance liquid chromatography, in 94 noncyanotic congenital heart disease patients. Plasma NE levels in 43 patients with CHF were significantly higher than those in the 51 patients without CHF (704 +/- 68 pg/ml vs 274 +/- 68 pg/ml, p < 0.001). Compared with the controls, the NE levels in the mild, moderate and severe CHF subgroups increased by 2.0, 2.6 and 3.7 fold, respectively. The E concentration did not significantly vary among the groups. The plasma NE levels correlated directly with the degree of left-to-right shunt (r = 0.46, p < 0.001) and pulmonary systolic pressure (r = 0.67, p < 0.001). Thus, a highly significant association was found between the level of plasma NE and severity of CHF symptoms. A follow-up study of 15 of the 30 CHF patients after surgery disclosed a significant decline in plasma NE (p < 0.001). The results of this study clearly demonstrate that plasma NE levels parallel the presence and severity of CHF in infants and children.