Coarctation, or stenosis of the aorta in the region of the ductus arteriosus, has been divided into two types.
The infantile type consists of a narrowing of the aorta between the origin of the left subclavian artery and the site of the ductus arteriosus. It is an exaggeration or persistence of the anatomic condition found in the fetus.
The adult type has no counterpart in normal intra-uterine life. It consists of a sharp constriction, at times complete obliteration, of the aorta, adjacent to the insertion of the ductus arteriosus. In this type, the symptoms of the condition may go unnoticed until some inter-current infection weakens the myocardium, or until some exertion increases the hypertension in the dilated vascular tree in the upper part of the body beyond the vascular reserve. Persons with such a condition may not complain of symptoms until the ages from 20 to 40. The condition has