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.