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目的:观察超声心动图斑点追踪方法能否早期发现和诊断异丙基肾上腺素(isoprenaline,ISO)引起的心脏功能异常。方法:将成年C57雄性小鼠分为对照组、ISO给药后3 d组和ISO给药后7 d组3组(n=6)。ISO组均为一次性给予ISO 5 mg/kg皮下注射,对照组给予生理盐水皮下注射,分别于给药后3 d和7 d应用传统超声心动图方法以及斑点追踪方法评价小鼠心脏功能。结果:包括径向应变(radial strain,RS)、径向应变率(radial strain rate,RSR)和纵向应变(longitudinal strain,LS)在内的心脏应变分析指标,均在ISO注射后3 d开始显著降低。另外,与心肌梗死的局灶性改变不同,ISO诱导的心肌肥厚在应变分析中表现为全心功能的异常。而相比之下,传统超声心动图仅能在ISO注射后7 d检测出E/E’显著升高,提示心脏舒张功能异常,而反映收缩功能的左室短轴缩短率(FS),以及反映心脏舒张功能的另外2个指标E/A和E’/A’均无显著差异。此外,心脏应变异常仅发生在ISO诱导的病理性心肌肥厚中,而并不出现在跑步训练诱导的生理性心肌肥厚中。结论:本研究发现基于超声心动图斑点追踪技术的心脏应变分析对心脏功能障碍的早期诊断比传统超声心动图更为敏感,而且可以用于区分病理性与生理性心肌肥厚。
Objective: To observe whether echocardiographic speckle tracking can detect and diagnose early abnormal cardiac function induced by isoprenaline (ISO). Methods: Adult C57 male mice were divided into control group, 3 d after ISO administration and 3 d after ISO administration (n = 6). The rats in ISO group were injected subcutaneously with ISO at a dose of 5 mg / kg. The control group was injected subcutaneously with physiological saline. The heart function of mice was evaluated by traditional echocardiography and dot-tracing methods on the 3rd and 7th day after administration. RESULTS: Cardiac strain analysis including radial strain (RS), radial strain rate (RSR) and longitudinal strain (LS) were all significant at 3 days after ISO injection reduce. In addition, unlike focal changes in myocardial infarction, ISO-induced cardiac hypertrophy manifests as an abnormality of cardiac function in strain analysis. In contrast, conventional echocardiography detected a significant elevation of E / E ’only 7 days after ISO injection, suggesting abnormal diastolic function and a shortening of the left ventricular fraction (FS) reflecting systolic function, as well as There was no significant difference in the other two indices E / A and E ’/ A’ that reflect diastolic function. In addition, cardiac abnormalities occurred only in ISO-induced pathological myocardial hypertrophy, but not in the physiologically-induced cardiac hypertrophy induced by running training. CONCLUSIONS: This study found that cardiac strain analysis based on echocardiographic speckle tracking is more sensitive to early diagnosis of cardiac dysfunction than traditional echocardiography and can be used to distinguish between pathological and physiological cardiac hypertrophy.