二维斑点追踪技术评价低温兔左室纵向功能

Evaluation of Left Ventricular Longitudinal Function in Rabbits under Hypothermia by Two-dimensional Speckle Tracking Technique

目的:探讨应用二维斑点追踪技术评价低温条件下兔左心室纵向功能的价值。方法:30只新西兰兔随机分成对照组(n=10),低温组A(n=10),低温组B(n=10)。先行常规心脏数据测量,然后采用组织多普勒(TDI),之后应用斑点追踪成像(STI)中的获取基底段、中间段、心尖段及整体水平SL、SrLs.SrL E,SrL A及分层应变技术获取3个长轴切面心内膜下、中层和心外膜下心肌收缩期纵向峰值应变(SL)。结果:①与对照组相比,A组心内膜下心肌LS值的减低,差异有统计学意义(P<0.05),B组3层心肌SL值的减低明显,差异有统计学意义(P<0.01)②与对照组相比,A组大部分纵向应变及应变率减低(P<0.05);B组基底段、中间段、心尖段及整体水平SL,SrL S、SrLE、SrLA均减低(P<0.01)结论:随低温时间延长,左室壁3层心肌SL值受累程度不同,心内膜应变较心外膜更加敏感,二维班点追踪技术比LVEF及TDI更早发现左室功能减低。

Purpose:To evaluate the value of two-dimensional speckle tracking technique in evaluating the longitudinal function of rabbit left ventricle at low temperature.Methods:Thirty New Zealand rabbits were randomly divided into control group(n=10),hypothermia group A(n=10)and hypothermia group B(n=10).The normal cardiad measurements were done first,and then tissue doppler imaging(TDI)was undergone.After application of speckle tracking imaging(STI),SL,SrL S,SrL E,SrL A of the basal segment,middle segment,apex segment and the whole were obtained.The myocardial systolic peak strain longitudinal(LS)of the endocardium,middle and epicardium along three long axis planes were obtained by layered strain technology.Results:①Compared with the control group,the LS value of subendocardial myocardium in group A was decreased,and the difference was with statistical significant(P<0.05).The LS value of 3 layers of myocardium in group B was significantly reduced,and the difference was with statistical significant(P<0.01).②Compared with the control group,most of the longitudinal strain and strain rate of group A was reduced(P<0.05).The values of SL,SrL S,SrL E and SrL A in basal segment,middle segment,apex segment and the whole in group B were all decreased(P<0.01).Conclusion:With the prolonged time of low temperature,the extent of involvement of LS in the 3-layer myocardium of the left ventricular wall is different.and the endocardial strain is more sensitive than the epicardium.The reduced left ventricular function was found earlier by two-dimensional specular tracing technology than that by LVEF and TDI。