Idiopathic hypertrophic obstructive cardiomyopathy causing severe right ventricular outflow tract obstruction in infancy.

Two infants with idiopathic hypertrophic obstructive cardiomyopathy, presenting as severe right ventricular outflow obstruction, are described. The nonspecific clinical features and an unexpected angiocardiographic appearance made correct diagnosis difficult. One of the infants was mistakenly diagnosed as having severe pulmonary valve stenosis. It is suggested that angiocardiography may be diagnostic. Attempted surgical correction was unsuccessful in the infants reported. Infants with idiopathic hypertrophic obstructive cardio- myopathy should be managed, at least initially, with beta-adrenergic receptor blocking agents.