Anatomically corrected transposition of the great arteries.

It has long been doubted whether or not it is possible for a transposed aorta to arise from a morphologically left ventricle, and for a transposed pulmonary artery to originate from a morphologically right ventricle, this having been designated anatomically corrected transposition by Harris and Farber in 1939. Such cases have been regarded as errors in observation (Lochte, 1898), as inexplicable variations of nature (Geipel, 1903), as embryologic-ally impossible and hence non-existent (Van Mierop and Wiglesworth, 1963), and as very probably non-existent (Van Praagh et al., 1964b). Hence, the principal purposes of this paper are (1) to provide convincing evidence that anatomically corrected transpositions do indeed exist, and (2) to consider some of the developmental and diagnostic implications of this fact. CASE REPORTS Case 1. This girl, 2 years and 20 days of age, died during a surgical attempt to relieve her pulmonary out-flow tract stenosis. The salient post-mortem findings were: dextrocardia (Fig. 1A); situs solitus of the viscera and atria, with a normal spleen (Fig. 2); left juxtaposition of the atrial appendages (both to the left of the great arteries) (Fig. lA); tricuspid atresia (Fig. 1E); large secundum type of atrial septal defect (Fig. 1B); ventricular d-loop (morphologically right ventricle to the right of the morphologically left ventricle) (Fig. 1 and 2); small ventricular septal defect (Fig. 1C, D); crista supraventricularis, largely above the morphologically left ventricle (Fig. 1C) but also above the morphologically right ventricle (Fig. ID); a combined conus (subaortic Received February 4, 1966. and subpulmonary) (Fig. 2) preventing fibrous continuity between the mitral valve and either semilunar valve (Fig. 1C, D); infundibular and valvar pulmonary steno-sis with a thickened bicuspid pulmonary valve (Fig. ID, E); I-transposition of the great arteries (transposed aortic valve to the left of the transposed pulmonary valve) (Fig. 1E and 2); transposed aorta arising entirely above the morphologically left ventricle (Fig. 1C, E); transposed pulmonary artery originating completely above the morphologically right ventricle (Fig. ID, E); right aortic arch (Fig. lA); and probe-patent ductus arteriosus (Fig. ID). Examination, using normal controls and the measurements of Lev, Rowlatt, and Rimoldi (1961), revealed cardiomegaly, combined atrial hypertrophy and enlargement , a thick-walled but small chambered right ventricle, left ventricular hypertrophy and enlargement, tricuspid atresia, mitral annulus larger than normal, pulmonary annulus smaller than normal, and aortic annulus within normal limits. Cardiac geometry (Van Praagh, Ongley, and Swan, 1964a) showed the following horizontal plane projections …