Double-outlet left ventricle with an intact ventricular septum. Clinical and autopsy diagnosis and developmental implications.

Abstract

Clinical, laboratory, and anatomic findings were presented concerning the first clinically diagnosed and autopsy proved case of origin of both great arteries from the morphologically left ventricle. The salient pathologic findings were: normally interrelated chambers (noninverted) in situs solitus; no ventricular septal defect; infundibular atresia; infundibulum related only to the right ventricle; absence of infundibular musculature beneath the great arteries, with aortic-mitral and pulmonary-mitral fibrous continuity; semilunar valves side by side, aortic to the right and pulmonary to the left, and at approximately the same height; thick-walled and small-chambered right ventricle with endocardial fibroelastosis of the apical half of the ventricle; hypertrophy and enlargement of both atria and of the left ventricle; absence of the left coronary ostium; and a fistula between the right ventricular apex and the anterior descending coronary artery. The main developmental implications of this rare case appear to be as follows: (1) strong support is given for the differential conal growth hypothesis concerning the morphogenesis of great arterial interrelationships; (2) truncus arteriosus communis would appear to have atresia, not absence, of the subpulmonary infundibulum; (3) the truncal septum does extend a short distance below the semilunar valves; and (4) the conus arteriosus appears to be a separate cardiac segment, not part of the right ventricle and not part of the great artelies.