Right and left ventricular ejection patterns in D-transposition of the great arteries assessed by pulsed Doppler echocardiography

Abstract

Pulsed Doppler echocardiography (PDE) was performed to evaluate the flow velocity patterns of the right (RVOT) and left ventricular outflow tracts (LVOT) in 10 patients with transposition of the great arteries (D-TGA). Twenty normal children served as controls. Systolic time intervals (STIs) and acceleration times (AcT) of the right and left ventricles were measured using PDE. The following results were obtained. In normal controls, the right ventricular pre-ejection period (RPEP) was shorter than the left ventricular pre-ejection period (LPEP), and the right ventricular ejection time (RVET) was longer than the left ventricular ejection time (LVET). The mean RPEP/RVET was 0.33 (range 0.25-0.42) and the mean LPEP/LVET was 0.38 (range 0.28-0.55). In normal controls, the flow velocity pattern of the RVOT had a dome-like contour with a peak velocity in mid-systole, and the mean AcT/RVET ratio was 0.50 (range 0.41-0.62); that of the LVOT had a triangular shape with a mean AcT/LVET ratio of 0.31 (range 0.24-0.38). In patients with D-TGA, the RPEP was longer than the LPEP and the RVET was shorter than the LVET. The mean RPEP/RVET was 0.53 (range 0.39-0.76) in patients with intact ventricular septum and 0.52 (range 0.54-0.60) in patients with ventricular septal defect (VSD). The RPEP/RVET was significantly greater in patients with D-TGA than in normal controls. The mean LPEP/LVET was 0.27 (range 0.16-0.42) in patients with intact ventricular septum, and 0.34 (range 0.23-0.40) in patients with VSD. The LPEP/LVET was significantly less in patients with intact ventricular septum than in normal controls. The flow velocity patterns of the RVOT and LVOT were the same as those for normal controls. The mean AcT/RVET ratio was 0.51 (range 0.49-0.55) in patients with intact ventricular septum and 0.49 (range 0.39-0.67) in patients with VSD. The mean AcT/LVET was 0.32 (range 0.27-0.38) in patients with intact ventricular septum and 0.28 (range 0.20-0.45) in patients with VSD. The flow patterns did not change after intraatrial baffle repair. Our studies indicate that the flow velocity patterns of the RVOT and LVOT in patients with D-TGA were not reversed, in spite of inverted afterloads.