CORRECTED TRANSPOSITION OF THE GREAT VESSELS OF THE HEART

Abstract

Corrected transposition of the great vessels is described, together with the probable embryologic basis for the defect. This defect has assumed great importance because of the necessity of recognizing its presence before surgical exploration for correction of the frequently associated ventricular septal defects and pulmonary stenosis. The presence of corrected transposition interferes with the surgical approach because of the anomalous coronary pattern and the inverted location of the defects. The physical and laboratory findings in 17 patients are tabulated and discussed. These included six with a ventricular septal defect, three with pulmonary stenosis, one with a ventricular and an atrial septal defect, one with a ventricular septal defect and left-sided atrioventricular valve stenosis, one with a ventricular septal defect and pulmonary stenosis, two with a reversing patent ductus arteriosus, and three with a ventricular septal defect and a small leftsided ventricle. The electrocardiogram usually shows A-V block, most often first degree, or A-V dissociation, inverted QRS patterns in the precordial leads (qR in V1 and RS in V6), peaked P waves in lead 2, widened QRS complexes, and upright T waves in the precordial leads, beginning either in RV4 or V1. Roentgenograms may demonstrate an unusual appearance of the upper left border of the heart. The main pulmonary artery may deeply indent the barium-filled esophagus, and the left pulmonary artery may be noted to be medially placed. The diagnosis can be definitely established by angiocardiography in the anteriorposterior view. The main pulmonary artery lies medially, and the aorta arises from the upper left border of the heart. Also diagnostic is the anomalous and difficult course taken by the cardiac catheter in entering the medially-placed pulmonary artery. This defect should be suspected in all patients where the pulmonary artery cannot be entered at cardiac catheterization. If pulmonary stenosis is present, the second sound below the left clavicle will not be as soft as usually noted with this defect. Certain considerations deemed of value to the surgical management of the associated intracardiac defects occurring in this series of patients with corrected transposition are presented.