Right heart volume characteristics in transposition of the great arteries

Right and left heart volume data were obtained during 44 cardiac catheterizations in 24 patients with complete transposition of the great arteries (TGA) prior to "corrective surgery." Patients were divided into three hemodynamic groups: I)TGA with intact ventricular septum, N = 23 studies in 13 patients, ages 1 day-22 months; II)TGA with ventricular septal defect (VSD), N = 12 studies in six patients, ages 7 days-15 months; III)TGA with VSD plus pulmonary stenosis, N = 9 studies in five patients, ages 5 days-5.6 years. In group I, right ventricular end-diastolic volume (RVEDV) averaged 170 plus or minus 52% of normal (P smaller than 0.001), RV ejection fraction (EF) was 0.48 plus or minus 0.09, 74% of normal (P smaller than 0.001), and RV systolic output (SO) was 123 plus or minus 34% (NS). In group II, RVEDV was 163 plus or minus 25% of normal (P smaller than 0.001), RVEF 0.59 plus or minus 0.08, 91% of normal (NS), and RVSO was 158 plus or minus 52% (P smaller than 0.02). In group III, RVEDV averaged 124 plus or minus 26% of normal (P smaller than 0.04), RVEF 0.58 plus or minus 0.15, 89% of normal (NS), and RVSO 125 plus or minus 57% (NS). Right atrial maximal volume was increased in 21 or 22 studies and averaged 185 plus or minus 47% of normal (P smaller than 0.001). RVEDV was greater than left ventricular end-diastolic volume in all but one patient in group I, but RVEDV/LVEDV was smaller than 1.00 in four VSD patients with very large pulmonary flows. A majority of patients with TGA without VSD have abnormal right heart function as indicated by an increased RVEDV and a low ejection fraction. Longitudinal studies of right ventricular performance in these patients continue to be important in assessment of current methods of therapy.