Functional Adaptations of the Right Ventricular Outflow Tract in Congenital Heart Disease

Despite intensive study in recent years, the natural history of many congenital heart lesions remains far from fully resolved, and it is only now becoming generally appreciated that physical forces as well as structural abnormalities may greatly influence their evolution both before and after birth. Nadas (1957) has pointed out, for example, that some malformations which can be identified in the newborn period do not assume their full pathognomonic features till months or even years later, and Wood (1962) in one of his last papers, re-emphasized his view that atrial septal defects normally behaved in this way.