摘要
目的通过超声斑点追踪成像技术（speckle tracking echocardiography，STE）评价大鼠自发性高血压（spontaneously hypertensive rats，SHR）左心室心肌局部收缩功能的特点。方法SHR大鼠8只，正常对照组为Wistar-Kyoto大鼠6只，14只大鼠均为雄性，9月龄，体重350～600g。应用GEVivid7超声诊断仪，M10S探头在二维成像模式下，经胸采集14只大鼠乳头肌水平左心室短轴切面的动态图像，连续采集大于6个心动周期，帧频大于190帧／s。然后将图像导入EchoPAC工作站脱机分析每个节段的环形峰值应变、收缩期环形峰值应变率、径向峰值应变和收缩期径向峰值应变率四个指标。结果SHR大鼠的左心室舒张末期内径，收缩末期内径，舒张末期容积和每搏量均明显低于Wistar大鼠（P〈0．05）。SHR大鼠左心室后壁的收缩末期厚度和舒张末期厚度有高于Wistar大鼠的趋势，但是差异不具有统计学意义。尽管SHR大鼠的左心室射血分数和缩短分数与WKY大鼠无统计学差异（p〉0．05），但下壁和间隔段的环形峰值应变，后壁、下壁和间隔段的收缩期环形峰值应变率以及除了侧壁和后壁段外其他节段的收缩期径向峰值应变率和6个节段的收缩期径向峰值应变率均值均低于Wistar大鼠的相应指标（P〈0．05）。前壁段收缩期环形峰值应变率明显低于下壁段和问隔段（P〈0．05）。结论高血压大鼠在射血分数和缩短分数正常的情况下随着左心室心肌的向心性重构，可能存在左心室局部收缩功能的障碍。Wistar大鼠收缩期环形峰值应变率在中间段宣壁的6个节段间存在异质性。STE能够用来准确识别和定量评价局部心肌收缩的异常。应变率反映心肌形变随时间变化的快慢，是评价收缩功能的非负荷依赖的指标，能提供局部心肌收缩功能状态更多有价值的信息。
Objective Our goal was to characterize left ventricular regional systolic function with speckle tracking echoeardiography （STE） in spontaneously hypertensive rats （SHR）. Methods Echocardiographic examinations were performed in 8 SHR and 6 normotensive Wistar-Kyoto rats. Two-dimendional acquisitions were analyzed off-line to measure circumferential and radial strain and strain rate in parasternal short-axis view at the level of papillary muscle. Results Despite apparently normal left ventricular （LV） eject fraction（EF） and fractional shortening（FS）, inferial and septal segmental circumferential peak strain, posterior, inferial and septal segmental circumferential peak systolic strain rate, and almost all segmental and average radial peak systolic strain rate except lateral and postal segments were significantly reduced in SHR （P〈0.05）. Anterier segmental circumferential peak systolic strain rate was significantly lower than that of infereral and septal segments in Wistar rats. Conclusions Hypertensive rats may have regional LV systolic function impairment despite having normal EF and FS. In normal Wistar rats, circumferential peak systolic strain rate of left ventricular myocardium has heterogeneity. STE can be used to accurately recognize and quantify abnormalities of regional myocardial deformation. Strain rate correlates well to loading independent indices of contractility and hence provides valuable information on regional contractile function.
出处
《西部医学》
2009年第12期2033-2036,共4页
Medical Journal of West China
关键词
超声斑点追踪成像技术
高血压
心肌收缩功能
应变
应变率
Speckle tracking echocardiography （STE）
Myocardial systolic funetion
Hypertension
Strain
Strain rate
