Circulatory effects of propranolol in children with Fallot's tetralogy: Observations with isoproterenol infusion, exercise and crying

Abstract

Twenty-five children with Fallot's tetralogy ranging in age from 10 months to 14 years were studied during diagnostic cardiac catheterization and angiocardiography. The effects of exercise, beta adrenergic stimulation with isoproterenol, and crying upon arterial oxygen saturation, pulmonary and systemic blood flow and the right to left shunt were determined before and after beta adrenergic blockade with propranolol. Both exercise and isoproterenol infusion resulted in a drop in arterial oxygen saturation and an increase in the right to left shunt. Propranolol, in doses which abolished the response to isoproterenol, produced a small rise (5–10%) in resting arterial oxygen saturation in 12 of 15 cases. The hemodynamic effects of exercise, however, persisted although they were less pronounced, in 4 of 6 cases. Crying in 2 infants was accompanied by a large drop in arterial oxygen saturation which was considerably reduced following administration of propranolol. It is concluded that beta adrenergic blockade with propranolol has little to offer in the management of older patients with Fallot's tetralogy; it may have some value in treating young infants and children, especially those with hypoxic spells.