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目的应用组织速度成像(TVI)和应变率成像(SRI)技术研究左室局部心肌缺血时左室压力变化对左房功能的影响并对比两种技术相关指标在病理状态下的变化趋势。方法11只犬行左冠状动脉前降支结扎,制作左室前壁急性心肌缺血模型,应用TVI和SRI技术分别测量缺血前后心房各壁的收缩期峰值速度(VS)、舒张早期峰值速度(VE)、舒张晚期峰值速度(VA)、收缩期应变率(SSR)、舒张早期应变率(ESR)和舒张晚期应变率(ASR)。同时记录二尖瓣口和肺静脉频谱各指标,并以左心导管记录缺血前后左室压力变化曲线。结果心肌缺血后左房各壁VE、VA、SSR、ESR和ASR与缺血前相比增高(P<0.001),左室舒张末期压力(LVEDP)增高且其缺血前后变化率LVEDP%分别与左房前壁、侧壁和下壁的VA变化率VA%呈正相关(r=0.72,0.73,0.83,P=0.05,0.05,0.002)。结论左房功能在局部心肌缺血时会受到增高的LV-EDP影响,表现为左房壁心肌纤维的运动能力随之增加;SRI技术各指标与TVI各指标变化相比在总体上具有同一趋势,但TVI指标在反映这一变化趋势上可能更加趋于稳定。
Objective To investigate the effect of left ventricular pressure (LVEDA) on left atrial function in patients with left ventricular local myocardial ischemia by using tissue velocity imaging (TVI) and strain rate imaging (SRI) techniques and to compare the trends of the two techniques in pathological conditions. Methods 11 dogs with left anterior descending coronary artery ligation were used to make the model of acute left ventricular anterior myocardial ischemia. TVI and SRI were used to measure the peak systolic velocity (VS), early diastolic peak velocity VE, VA, SSR, ESR and ASR were measured. At the same time, mitral valve and pulmonary venous frequency spectrum were recorded. Left ventricular catheter was used to record left and right ventricular pressure changes before and after ischemia. Results After myocardial ischemia, the levels of VE, VA, SSR, ESR and ASR in left atria were increased compared with those before ischemia (P <0.001) and the left ventricular end diastolic pressure (LVEDP) There was a positive correlation between the rate of change of VA and VA in the anterior wall, lateral wall and inferior wall (r = 0.72,0.73,0.83, P = 0.05,0.05,0.002). Conclusions Left atrial function is affected by increased LV-EDP during local myocardial ischemia, which shows that myocardial function of left atrial wall increases with the increase of left ventricular function. The indexes of SRI technique have the same tendency as those of TVI , But TVI indicators may be more stable in reflecting this trend of change.