Fig. 5.

Echocardiographic evidence of pulmonary artery hypertension in irradiated rats. Columns represent control rats (left-side) or irradiated rats (right-side) and rows represents four different imaging windows: (1) parasternal short-axis, (2) apical four-chamber views using B-mode at end-diastole to demonstrate right ventricular remodeling, (3) high parasternal short-axis view with pulsed-wave Doppler is used to detect pulmonary artery flow, and (4) apical four-chamber view with color Doppler is used to detect tricuspid regurgitation (red arrows). The parasternal short axis and apical four-chamber views show right ventricular dilatation with concomitant decrease in left ventricle. The pulmonary artery profiles reflect the presence of pulmonary hypertension. Normal, round-shaped flow profile is found in the control hearts, whereas a blunted flow profile with a sharp peak at early systole and a decreased acceleration time and increased deceleration is seen in the irradiated rat heart. There is no detectable tricuspid regurgitation by color Doppler in control rats, but tricuspid regurgitation is common in the irradiated group. R = right, L = left, A = atrium, V = ventricle.