Heparinization during percutaneous cardiac catheterization in children.

The effect of heparin on blood clotting was studied by measuring the activated clotting time (ACT) in 120 infants and children with congenital heart disease after a single intravenous bolus of 100 IU heparin/kg body weight. Before heparinization, infants and children with cyanotic heart disease showed signs of hypocoagulation. Heparin bolus led to a threefold increase of ACT after 15 min. After 1 h, the ACT was still two times the normal value. Any further administration of heparin may be based on ACT monitoring.