[Evaluation of the myocardial systolic function and ventricular remodeling of rats with experimental myocardial infarction by strain/strain rate imaging and MMP-9].

OBJECTIVE: To evaluate the myocardial systolic function and ventricular remodeling in heart failure rat induced by myocardial infarction (MI) with S/SRI and MMP-9. METHODS: A total of 70 male SD rats were randomly assigned to 4 groups: 4 weeks and 8 weeks MI (anterior descending branch of left coronary artery were ligated), sham operation (thoracotomy without ligation of coronary artery) and non-operated control group. The regional myocardial systolic function of rats was quantified with S/SRI. The myocardial MMP-9 expression was detected by Western blot. RESULTS: In the 4 weeks MI group, all segment's Ssys, SRsys, the strain of end-systole were reduced while PSI was increased compared to sham and non-operated group with the exception of the inferior wall. These changes were more significant in 8 weeks MI group compared to the 4 weeks MI group. In the 4 weeks MI group, the expression of MMP-9 was significantly upregulated than the sham operation group and this upregulation was more significant at 8 weeks post MI. CONCLUSIONS: S/SRI can quantitative evaluate the regional systolic function of heart failure rat induced by myocardial infarction. Progressive upregulation of myocardial MMP-9 expression paralleled the deterioration of regional systolic function in this heart failure rat model.

[Evaluation of myocardial systolic function of heart failure induced by myocardial infarction in rats with strain and strain rate imagine].

OBJECTIVE: To quantitatively detect variation in regional myocardial systolic function in heart failure rat model induced by myocardial infarction by strain and strain rate imaging. METHODS: Seventy 2-month-old adult male SD rats were randomly assigned to 4 groups: a 4-week and a 8-week group after the operation (each n = 25) had thoracotomy, the pericardium opened and the anterior descending branch of left coronary artery ligated; a sham operation group (n = 10) had thoracotomy and the arcula cordis opened, but did not ligate the artery; a control group (n = 10) had no treatment. The changes of general state of health of the rats were observed and recorded every day. To assess the change of heart function, echocardiography was used at the end of the 4th week and 8th week after the surgery. To evaluate the change of heart function in heart failure rats, we quantitatively analyzed the regional myocardial systolic function in all rats by strain and strain rate imaging and myocardium to detect the level of MMP-9 at the end of the 4th week and 8th week. The repeatability and discrepancies of the results were all analyzed. RESULTS: Obviously objective signs of heart failure manifested themselves in the survived mice 10 to 14 days after the surgery. Compared with the control group and the sham operation group, the fraction shortening (FS) and ejection fraction (EF) of the 4-week group after the operation were lower (P < 0.05), the left ventricle index (LV index) of the 8-week group after the operation was higher, left ventricle posterior wall index (LVPW index), interventricular septum index (IVS index), FS, and EF of the 8-week group after the operation were lower (P < 0.05), EF and FS of the 8-week group after the operation were lower than those of the 4-week group. Except the mid-inferior wall and base-inferior wall, the systolic peak strain, systolic peak strain rate, the strain of end-systole in all segments of the operation group were lower than those of the other 2 groups (P < 0.05). The post-systolic strain index of the operation group was higher than that of the other 2 groups (P < 0.05). CONCLUSION: Strain and strain rate imaging of echocardiography can quantitatively evaluate the changing of regional myocardial systolic function in the heart failure rat model induced by myocardial infarction, with good repeatability.