REGULATION OF SYMPATHETIC ACTIVITY IN CHILDREN WITH VARIOUS CONGENITAL HEART-DISEASES

We studied the alpha- and beta-adrenoceptor activity and catecholamine and cAMP levels in 112 children and infants admitted to the hospital for diagnostic or interventional catheterization of tetralogy of Fallo t, ventricular septal defects with or without hypertension, pulmonary stenosis, coarctation of the aorta, and various complex cyanotic conge nital cardiac diseases and compared them with 14 children undergoing t ranscatheter occlusion of patent ductus arteriosus with insignificant left-to-right-shunts. The mean total platelet alpha-adrenoceptor densi ty of the study population was elevated by 73%. Both the increases in acyanotic (p < 0.05) and cyanotic (p < 0.005) patients as well as the difference between the two groups (p < 0.01) were significant. Based o n the congenital disease classification, the elevation in receptor den sity was also significant in all groups of patients, except coarctatio n of the aorta. On the other hand, the mean lymphocyte beta-adrenocept or density was attenuated by 27%, showing significant difference betwe en the acyanotic and the patent ductus arteriosus groups, but none bet ween acyanotic and cyanotic or cyanotic and the patent ductus arterios us groups. Among the congenital groups, only the left-to-right shunts and the pulmonary stenosis group showed significant (p < 0.05) decreas e in beta-adrenoceptor density, whereas the affinity of all the groups toward [I-125]iodocyanopindolol was hardly influenced. The plasma lev els of all three catecholamines, norepinephrine, epinephrine, and dopa mine, were elevated, but cAMP remained unchanged. It seems that the sy mpathetic nervous system responds to changes triggered by some congeni tal heart diseases by' stimulating alpha-adrenoceptors, which may be f urther increased by cyanosis and an attenuation of beta-adrenoceptors associated with an increase in plasma catecholamine levels.