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目的应用扩张型心肌病(DCM)小鼠模型探讨组织多普勒显像(TDI)评价早期心肌功能障碍的可行性。方法应用Vevo 770超声生物显微镜和30～40 MHz高频探头,分别在小鼠生后第3个月(G1组,n=12)、第6个月(G2组,n=11)和第9个月(G3组,n=10)对携带ZASP4突变的33只DCM小鼠进行M型、二维及TDI超声心动图检查。以M型和二维超声评价整体心脏功能以获取短轴缩短率(FS)和射血分数(EF)。TDI的取样容积置于左心室后壁,并将其分为基底段、中间段和心尖段以获取收缩和舒张峰值速度。结果 M型和二维超声测量G1、G2组的EF与FS之间均无统计学差异(P>0.05),而G3组则明显降低(P<0.01)。以TDI测量的G2组基底段和中间段收缩峰值速度明显低于G1组[(28.6±4.3)mm/s vs(45.8±12.0)mm/s,(26.3±5.3)mm/s vs(38.6±12.6)mm/s,P<0.01];舒张峰值速度也低于G1组[(32.3±6.3)mm/s vs(53.3±12.6)mm/s,(27.3±7.2)mm/svs(41.9±12.0)mm/s,P<0.01)],G3组基底段和中间段的峰值速度相比,G1和G2组减少更为明显(P<0.01)。结论利用高频显微镜进行TDI评测是可行的;并且TDI检测DCM小鼠模型的早期心功能障碍更敏感。
Objective To investigate the feasibility of using tissue Doppler imaging (TDI) to evaluate early myocardial dysfunction in dilated cardiomyopathy (DCM) mouse model. Methods Using Vevo 770 ultrasound bio-microscope and 30-40 MHz high-frequency probe, the mice were sacrificed at the third month after birth (G1, n = 12), the sixth month (G2, n = 11) M-type, two-dimensional and TDI echocardiographic studies were performed on 33 DCM mice carrying the ZASP4 mutation (G3, n = 10). Overall heart function was assessed by M-mode and two-dimensional sonography to obtain short axis shortening (FS) and ejection fraction (EF). The volume of the TDI is placed in the posterior wall of the left ventricle and divided into basal segments, medial segments and apical segments for systolic and diastolic peak velocities. Results There was no significant difference between EF and FS in G1 and G2 groups (P> 0.05), while G3 group (P <0.01). The peak systolic velocity of basal segment and middle segment of G2 group measured by TDI was significantly lower than that of G1 group [(28.6 ± 4.3) mm / s vs (45.8 ± 12.0) mm / s, (26.3 ± 5.3) mm / s vs (32.3 ± 6.3) mm / s vs (53.3 ± 12.6) mm / s, (27.3 ± 7.2) mm / s vs (41.9 ± 12.0) mm / s, P < ) mm / s, P <0.01). Compared with the peak velocity in the middle and basal segments of the G3 group, the decrease was more significant in the G1 and G2 groups (P <0.01). Conclusions TDI is feasible using high-frequency microscopy; and TDI is more sensitive to early cardiac dysfunction in DCM mice.