Quantification of Left Heart Volume and Systolic Output in Transposition of the Great Arteries

Left heart volume and output were calculated by using cineangiocardiograms from 64 studies in 44 patients with transposition of the great arteries (TGA). The majority of patients who had an intact ventricular septum and were less than 6 months of age showed normal end-diastolic volumes (LVEDV) and systolic output (LVSO), while patients in this hemodynamic group more than 6 months of age had elevated volumes and outputs. The presence of a patent ductus arteriosus (PDA) was associated with an increase in LVEDV and LVSO. Patients with a ventricular septal defect (VSD) and no pulmonary stenosis (PS) had increased volumes and outputs with the average values for LVEDV and LVSO significantly greater for the VSD group than for the intact-septum group. Patients with a VSD and PS showed normal values for LVEDV and LVSO. The ejection fraction was normal in all patients. Left atrial maximal volume (LAMax) was normal in the majority of patients with an intact ventricular septum and no PDA, but was increased in patients with a VSD and no PS. The values for LVEDV, LVSO, and LAMax showed little or no change following balloon atrial septostomy in the majority of patients. Four patients studied before and after corrective surgery demonstrated decreases in LVEDV and LVSO to normal values following successful interatrial venous transposition. Left heart volume variables derived from cineangiocardiograms can aid considerably in hemodynamic evaluation of patients and in estimation of pulmonary blood flow.