This presentation will demonstrate the essential features of tetralogy of Fallot in the infant and child before surgery, as well as some noteworthy features in the foetus. The four features, namely, subpulmonary stenosis, ventricular septal defect, aortic override, and right ventricular hypertrophy, can all be easily demonstrated by echocardiography. In addition, morphology of the pulmonary valve and the main and branch pulmonary arteries can be seen. The position of the coronary arteries and the major variants of proximal coronary anatomy can be defined. The arch anatomy and the presence of associated major aortopulmonary collateral arteries can be defined. All these features can be demonstrated in the foetus as well, after the first trimester, and the presence of major aortopulmonary collateral arteries can be seen more clearly because the lungs, being fluid filled, aid in ultrasound and do not provide the barrier that the air-filled lung presents after birth.
