Surgical correction in complete levotransposition of the great arteries with an unusual subaortic ventricular septal defect.

Six children with an uncommon variant of complete (that is, physiologically uncorrected) transposition of the great arteries are described. In this malformation, levoposition of the aorta is coincident with situs solitus and concordant atrioventricular relations. All patients underwent successful surgical correction. Four had a ventricular septal defect; in three, the defect was subaortic and because of its unusual anatomic features, a right ventriculotomy was required for repair. Interatrial transposition of venous return was carried out in all cases by insertion of a baffle, as in complete dextrotransposition of the great arteries. The surgical verification of the arterial positions in these cases illustrated the fallibility of the so-called loop rule. The significance of the cases in relation to terminology, classification and morphogenesis of this variant is discussed.