Transmural mechanics at the infarcted myocardium of a dog model of acute myocardial infarction
10.3969/j.issn.2095-4344.2014.27.006
- VernacularTitle:构建急性心肌梗死模型犬梗死区的跨壁力学变化
- Author:
Junli WANG
;
Lixue YIN
;
Liping FEI
;
Qingying NIU
;
Wenhua LI
- Publication Type:Journal Article
- Keywords:
myocardial infarction;
myocardium;
ultrasonography;
echocardiography
- From:
Chinese Journal of Tissue Engineering Research
2014;(27):4293-4298
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND:Acute myocardial infarction with acute onset is dangerous, but the aided diagnosis for hyperacute disease mainly depends on electrocardiogram. The advantages of tissue Doppler strain imaging were utilized to help early diagnosis of acute myocardial infarction.
OBJECTIVE:To observe left ventricular transmural peak radial strain and strain time-to-peak of subendocardiac muscle, midmyocardium and subepicardiac muscle using tissue Doppler strain imaging in dogs before and after acute myocardial infarction, and to assess its mechanical characteristics.
METHODS:A total of 16 Beagle dog models of acute myocardial ischemia were established by ligating left anterior descending coronary artery. The two-dimensional apical short-axis views of the left ventricle in five complete cardiac cycles were acquired and stored in TDI-Q workstation before and after acute myocardial ischemia. Transmural peak radial strain and strain time-to-peak of segment, subendocardiac muscle, midmyocardium and subepicardiac muscle at infarct region and baseline were observed.
RESULTS AND CONCLUSION:Peak radial strains at infarct and subendocardiac muscle, midmyocardium and subepicardiac muscle were decreased compared with the baseline (P<0.05). Peak strain gradient disappeared in each layer of infarct myocardium. Strain time-to-peak of the whole segment and infarct myocardium at different layers was significantly postponed (P<0.05). There was a positive correlation of peak radial strain between subendocardium and segment as wel as between medium and segment at baseline (r=0.617, P<0.01;r=0.556, P<0.01). This relationship disappeared at infarct region (r=0.338, P>0.05;r=0.218, P>0.05). Results indicated that after acute myocardial infarction, peak strain gradient disappeared at different layers at infarct region. Acute myocardial ischemia induces peak radial strain decrease at subendocardium, medium, subepicardium and strain time-to-peak at infarct region was significantly postponed, which reflected abnormal cardiac structure and dysfunction, resulted in uncoordinated cardiac motion and asynchronous heart movement. This may be an important mechanical mechanism triggering heart failure.
