Right-to-left shunts with right ventricular hypertrophy: Pathologic aspects

Abstract When a right-to-left shunt occurs on the basis of congenital cardiac disease, a major dividing point in differential diagnosis is whether or not right ventricular hypertrophy is present. When right ventricular hypertrophy is present, the shunt may occur either at the ventricular or atrial level. When the shunt occurs at the ventricular level, cases may be subdivided according to the vascular connections with the right ventricle into the following groups: (1) connection of the ascending aorta and of the pulmonary trunk with the right ventricle, (2) connection of the ascending aorta alone with the right ventricle, and (3) connection of the pulmonary trunk and of the descending aorta (through a PDA) with the right ventricle. When a transatrial right-to-left shunt occurs, it is on the basis either of 1.(1) right ventricular hypertrophy incident to pulmonary stenosis or atresia or 2.(2) total anomalous connection of the pulmonary veins.