Left ventricular wall thickness in complete transposition of the great arteries.

Age-related changes in left ventricular wall thickness were studied in 92 autopsy specimens of complete transposition of the great arteries (TGA) and in 189 normal hearts. By means of morphologic and clinical hemodynamic criteria, three groups were defined: Group II, TGA with intact ventricular septum (low left ventricular pressure): Group II, TGA with ventricular septal defect but without pulmonary stenosis (systemic left ventricular pressure combined with volume overload); and Group III, TGA with ventricular septal defect and pulmonary stenosis (systemic left ventricular pressure). At birth, the left ventricular thickness for the three groups did not significantly differ from normal. In group I, the left ventricular thickness remained constant with age up to 4 years and, accordingly, was significantly less after 4 months of age than that both in normals and in Groups II and III. In those Group II specimens from patients without irreversible pulmonary vascular disease, the left ventricular thickness was similar to that of normal hearts. The left ventricular thickness in Group III increased, with age in a manner similar to that of normal hearts. If left ventricular wall thickness correlates with potential ventricular function, then this measurement, combined with other clinical data, may help to predict the ability of the left ventricle to perform systemic work following one of the arterial switch operations. Sequential determinations of wall thickness may be attained noninvasively by echocardiography.