摘要目的 应用心肌造影超声心动图(MCE)结合速度向量成像(VVI)技术研究糖尿病(DM)大鼠左室心肌微循环障碍与心肌收缩功能损伤之间的相关关系.方法 雄性SD大鼠23只,腹腔注射链脲菌素复制DM模型,另23只体质量匹配的雄性SD大鼠腹腔注射等量生理盐水作为对照.分别在静息状态和潘生丁负荷后,对两组大鼠(12周)乳头肌水平左室短轴行MCE和VVI检查,分别测定心肌血流量(MBF)、心肌血流储备(MFR)、收缩期最大圆周应变率(SRc)及其储备,分析MBF/MFR与SRc/SRc储备之间是否存在相关关系.结果 DM组大鼠的SRc、SRc储备、MBF及MFR均较对照组显著减低.DM组大鼠SRc与MBF之间没有明显相关性,而SR.储备与MFR之间呈现显著的负相关.结论 静息状态下,心肌血流量的降低并不是圆周应变率降低的主要决定因素,而潘生丁负荷后,心肌血流储备的降低可能是心肌圆周应变率储备降低的主要决定因素.

abstractsObjective To investigate whether myocardial dysfunction and perfusion impairment had happened in diabetes mellitus(DM)rats,and to assess the relationship between them by using myocardial contrast echocardiography(MCE)and velocity vector imaging(VVI).Methods MCE and VVI were performed from the short-axis views of the mid-left ventricular level both at rest and after dipyridamole stress in control rats and DM rafs(12 weeks after induction with streptozotocin).MCE-derived myocardial blood flow(MBF)and myocardial flow reserve(MFR)and VVI-derived circumferential strain rate(SRc)and SRc reserve were obtained.Results SRc(absolute value)and MBF in the DM group were significantly lower than those in the control group at rest(P =0.03 for SRc and P =0.005 for MBF).SRc reserve and MFR in the DM group were significantly lower than those in the control group after dipyridamole stress (P =0.000 for SRc reserve and P =0.014 for MFR).There was no significant correlation between SRc and MBF at rest in the DM group(r =0.189,P =0.453).However,significant negative correlation existed between SRc reserve and MFR(r =-0.658,P =0.003).Conclusions Both myocardial systolic function and perfusion are impaired in DM rats.The decrease of MBF might not be the predominant determinant of myocardial systolic dysfunction at rest.However,the impairment of MFR could be an important contributor to the decrease of myocardial contractile reserve.