Objective To evaluate the left ventricular diastolic dysfunction by tissue Doppler imaging (TDI)in a suprarenal abdominal aortic coarctation model of Lewis rats. Methods Thirty male Lewis rats at age of 8 weeks were used. Myocardial hypertrophy model was obtained by suprarenal abdominal aorta banding with ligation. Mitral annular velocity measurement by TDI and regular two-dimensional echocardiography with M mode were examined at baseline and at 10-,20-,30-and 40-day post banding.Results Compared with baseline,the left ventricular end diastolic and end systolic wall thickness and ventricular dimension were progressively increased,while ejection fraction(EF)and fraction shortening(FS)were decreased(P＜0.0 1).The left ventricle demonstrated centrifugal myocardial hypertrophy.Peak myocardial systolic velocity(Sa)at the mitral annulus did not change significantly throughout this study and there was no significant correlation with EF(r=0.216,P=0.071),and peak myocardial early diastolic (Ea),late diastolic(Aa)at the mitral annulus and Ea/Aa indices also were not stable after aortic banding and there were no significant difference in repeated measures at different time(P＞0.05).But the E/Ea wasincreased and the index had a statistically significant difference(P＜0.001).Conclusions The left ventricleshowed centrifugal myocardial hypertrophy in Lewis rats with abdominal aortic banding.E/Ea radio was a sensitive and stable index to evaluate left ventricular diastolic dysfunction.%目的 采用组织多普勒显像(TDI)评价Lewis大鼠肾上腹主动脉缩窄后心脏的舒张功能变化.方法 选取30只8周龄雄性Lewis大鼠,缩窄其肾上腹主动脉至0.8 mm,造成左室心肌肥厚模型,分别于腹主动脉缩窄术前和术后10 d、20 d、30 d、40 d进行二尖瓣环组织多普勒频谱和常规超声的测量.结果 大鼠心脏前后壁厚度随着随访时间的延长而增加,左室舒张末和收缩末内径也随之增大,左室射血分数(EF)及短轴缩短率(FS)呈下降趋势,以上指标差异均有统计学意义(P＜0.01),大鼠心脏表现为离心性肥厚.二尖瓣环TDI收缩期峰值(Sa)变化趋势不明显,并与EF值相关性较差(r=0.216,P=0.071).无论舒张早期峰值(Ea)、舒张晚期峰值(Aa)和Ea/Aa指标在随访中均无稳定的变化趋势,差异无统计学意义(P＞0.05).而唯有E/Ea一直呈上升趋势,并且经重复测量方差分析,差异有统计学意义(P＜0.001).结论 Lewis肾上腹主动脉缩窄大鼠心脏变化特点主要表现为离心性肥厚,E/Ea值能敏感、稳定地反映大鼠舒张功能的变化过程.
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