Diagnosis of right ventricular outflow obstruction in infants by cross sectional echocardiography.

Cross sectional echocardiographic studies were assessed prospectively in 58 infants in whom right ventricular outflow obstruction was subsequently shown angiographically. A subcostal cut was used to display simultaneously the short axis of the aortic root and the long axis of the right ventricular outflow tract. This facilitated the differentiation of the common right ventricular outflow tract obstructive lesions. Tetralogy of Fallot was diagnosed correctly in 22 of 26 infants; pulmonary atresia with intact septum in all of 14 neonates; isolated severe pulmonary valve stenosis in all of nine infants; and pulmonary atresia with ventricular septal defect in eight of nine infants. The subcostal approach is the technique of choice for evaluating right ventricular outflow tract obstruction as it is more reliable than the left parasternal approach.