Newborn infants with severe atelectasis seldom survive long enough to develop secondary cardiac changes other than dilatation, but in rare instances survival is sufficiently prolonged to permit hypertrophy of the myocardium of the right ventricle, giving the heart the characteristic anatomic configuration of cor pulmonale as seen in older age groups. The clinical findings associated with these secondary changes in the heart may be more striking than those of the primary disease of the lungs, and because the clinical behavior of the atelectasis-cor-pulmonale lesion-complex can so closely simulate that of a congenital malformation of the heart, the correct etiologic diagnosis is often made only after death and examination of the lungs and heart at necropsy. Apparently these facts are not generally appreciated, for in the modern English language literature there are only two reports * which consider in detail the pulmonary heart disease secondary to atelectasis of the newborn.
PEACE RJ. Cor Pulmonale in Newborn Infants. AMA Am J Dis Child. 1955;89(5):567-571. doi:10.1001/archpedi.1955.02050110681007