We investigated whether pulsed Doppler echocardiography can assess the progression of pulmonary hypertension (PH) and the right ventricle (RV) function in rats.
Six-week-old S-D rats were injected with monocrotaline (MCT 60mg/kg) or vehicle and underwent serial echocardiography. The ratio of pulmonary acceleration time to ejection time (AcT/ET) and RV Tei index were measured by pulsed Doppler echocardiography. Furthermore, gross anatomic evaluation of heart and measurements of pulmonary arterial systolic pressure (PASP) were performed.
PASP were significantly elevated in MCT group two weeks after injection and more elevated four weeks after injection. The ratio of RV weight to left ventricle plus septum weight were not significantly different between two groups two weeks after injection but were significantly increased in MCT group four weeks after injection. Similarly, AcT/ET was significantly less in the MCT group two weeks after injection (MCT: 0.30+/-0.01 vs control: 0.39+/-0.01 p<0.001) and became more less four weeks after injection (MCT: 0.21+/-0.01 vs control: 0.39+/-0.01 p<0.001). RV Tei index was not significantly different between two groups two weeks after injection but significantly greater in the MCT group four weeks after injection (MCT: 0.70+/-0.06 vs control: 0.34+/-0.02 p<0.001). Furthermore, AcT/ET correlated inversely with PASP (r=-0.86 p<0.001) and RV Tei index correlated linearly with the ratio RV weight to left ventricle plus septum weight (r=0.79 p<0.001).
We concluded that AcT/ET and RV Tei index can assess the progression of PH and RV dysfunction due to RV hypertrophy.