WITH THE introduction of cardiac catheterization and angiocardiography into the diagnostic field of heart disease, more specific and exacting investigations of cardiac lesions have been accomplished. These have been associated with great strides in the surgical treatment, with the result that several of the major cardiac malformations are now amenable to surgical repair.
At present, a major focus of surgical correction is being directed toward defects in the atrial * and ventricular septa.† Since the operative indications and surgical approach are quite different, it has become important to separate the two lesions definitively, both by clinical and by laboratory methods. Although the clinical diagnosis of these lesions is often not difficult in older children and adults, it has been our experience that the differential diagnosis is often difficult in infants and in preschool children. It is our purpose to discuss the natural course of patients with ventricular and atrial septal defects