Wall thickness of ventricular chambers in transposition of the great arteries: surgical implications.

One hundred four specimens of complete transposition of the great arteries (TGA) were studied. The free wall thickness of the left (LV-T) and right (RV-T) ventricular chambers and the left ventricular/right ventricular (LV/RV) thickness ratio for all hearts were analyzed. A control group of 63 normal hearts was also studied. Specimens of TGA were divided into four groups: (1) TGA with intact ventricular septum (TGA + IVS); (2) TGA with ventricular septal defect (TGA + VSD); (3) TGA with a large patent ductus arteriosus (TGA + PDA); (4) TGA with pulmonary stenosis (TGA + PS). In Group I, LV-T was under the 95% confidence limits for normality after 8 months of age, and in Group II, the same was true after 18 months of age. For all groups the RV-T was above the 95% confidence limits for normality from the first month of age. The LV/RV ratio was under 1 in every group. Group I showed a significant decrease in the LV/RV ratio after the neonatal period (p less than 0.005). The potential failure of the left ventricle after anatomic correction of TGA is explained by a multifactorial hypothesis. In view of the ventricular wall thickness findings, we do not recommend the anatomic correction after 8 months of age in Group I or after 18 months in Group II.