多普勒超声心动图应变技术对收缩后缩短现象的实验研究

目的 :应用超声应变技术定性评价心肌缺血前后的收缩后缩短变化及特征。方法 :在对 2 7只开胸犬进行冠状动脉左前降支结扎以建立心肌缺血模型 ,实验结束后对心肌进行美蓝灌注和节段心肌做病理检查以确定缺血范围。以应变峰超过主动脉瓣关闭线为收缩后缩短的判断标准 ,计算出心肌缺血前后收缩后缩短的节段数并进行比较。结果 :结扎前 ,在 43 2个显示清楚的节段中 ,有 5 3个 ( 1 2 .3 % )节段存在收缩后缩短现象 ;结扎后 ,收缩后缩短现象增加 ,在 3 96个显示清楚节段中 ,有 2 5 8个 ( 65 .2 % )节段出现收缩后缩短现象 ( P <0 .0 5 )。未缺血区收缩后缩短现象也增加 ,在 1 96个显示清楚的节段中有 41个节段 ( 2 0 .9% ) ( P <0 .0 5 )。结论 :超声应变积分可定性评定节段心肌收缩后缩短现象 ,依据该现象可分析节段心肌缺血情况。

EVALUATION OF THE POSTSYSTOLIC SHORTENING BY STRAIN DOPPLER ECHOCARDIOGRAPHY:AN EXPERIMENTAL STUDY

Objective: This study was aimed to identify postsystolic shortening phenomena (PSS) of the myocardium before and after the ischemia. Methods: Twenty-seven open-chested dogs were given ligature of left anterior descending branch (LAD) to make myocardial ischemic models. The peak of the strain curve which was lated after the aortic valve closure was defined PSS. Ischemic regions were defined by methylene blue and pathologic analysis. Results: In 432 segments, 53 (12.3%) segments existed PSS before the ligature. PSS was increased after the LAD ligature to 258 (65.2%) in 396 segments (P<0.01). And in the unischemic regions, it was increased from 27/215 (12.6%) segments to 41/196 (20.9%) segments (P<0.05). Conclusion: SDE would appear to be a promising new noninvasive approach to the clinical evaluation of PSS, and PSS could be used to evaluate myocardial ischemia.