ABSTRACT
Objective To evaluate the left ventricular (LV) systolic dyssynchrony after the acute myocardial infarction (AMI) with two-dimensional speckle tracking echocardiography (STE). Methods STE were performed in 65 patients within 72 h of AMI and compared with 60 age- and sex-matched healthy volunteers. The peak longitudinal strain (LS_(peak)) was measured at LV myocardium. LV dyssynchrony was defined as an interval ≥130 ms for the absolute difference in time to peak radial strain for the anteroseptal wall versus the posterior wall (TAS-POST). Size of myocardial infarction (MIS)was confirmed by wall-motion score index (WMSI). Results The LS_(peak) and LV ejection fraction (LVEF) were lower, and WMSI and TAS-POST were larger in AMI patients compared with controls. Forty-two patients had developed LV dyssynchrony (64.62%), and there were strong correlation between LV dyssynchrony (TAS-POST) and LS_(peak), LVEF, and WMSI (MIS). MIS was the most independent predictor for systolic dyssynchrony. Conclusion AMI with normal QRS can induce LV dyssynchrony, which is mainly determined by MIS. STE is a reliable technique for accurate evaluation of LV synchrony.
ABSTRACT
Triphenyltetrazolium chloride (TTC) staining and echocardiography (ECHO) are methods used to determine experimental myocardial infarction (MI) size, whose practical applicability should be expanded. Our objectives were to analyze the accuracy of ECHO in determining infarction size in rats during the first days following coronary occlusion and to test whether a simplified single measurement by TTC correctly indicates MI size, as determined by the average value for multiple slices. Infarction was induced in female Wistar rats by coronary artery occlusion and MI size analysis was performed after the acute (7th day) and chronic periods (after 4 weeks) by ECHO matched with TTC. ECHO and TTC showed similar values of MI size ( percent of left ventricle perimeter) in acute (ECHO: 33 ± 11, TTC: 35 ± 14) and chronic (ECHO: 38 ± 14, TTC: 39 ± 13 periods), and also presented an excellent correlation (r = 0.92, P < 0.001). Although measurements from different heart planes showed discrepancies, a single measurement acquired from the mid-ventricular level by TTC was a good estimate of MI size calculated by the average of multiple planes, with minimal disagreement (Bland-Altman test with mean ratio bias of 0.99 ± 0.07) and close to an ideal correlation (r = 0.99, P < 0.001). In the present study, ECHO was confirmed as a useful method for the determination of MI size even in the acute phase. Also, the single measure of a mid-ventricular section proposed as a simplification of the TTC method is a satisfactory prediction of average MI extension.
Subject(s)
Animals , Female , Rats , Coloring Agents , Myocardial Infarction/pathology , Myocardial Infarction , Tetrazolium Salts , Echocardiography , Predictive Value of Tests , Rats, Wistar , Reproducibility of ResultsABSTRACT
Cardiomyocytes hypoxia resulting from ischemia is a major pathological factor in ischemic heart disease(IHD), and diabetes is one of the most common complications in IHD. myocardial damages aggravate and prognosis is worse in patients with coronary heart disease and diabetes, which is probably concerned with the reduction of hypoxia-inducible factor 1 (HIF-1) expression. But the mechanisms of HIF-1 signal transduction system in diabetes are not clear. In recent years, many studies have indicated that increasing expression and activity of HIF-1? in IHD can promote neovascularization and cardiomyocytes survival, decrease ischemical reperfusion injury and myocardial infarction (MI) size, and increase myocardial function. Therefore regulating expression and activity of HIF-1? becomes a new way to treat IHD. Myocardial infarction models were made in GK diabetes rats through the ligation of left anterior descending coronary artery (LADCA). By using immunohistochemistry staining and RT-PCR methods, results suggested that HIF-1? expression decreased and myocardial infarction size increased in GK diabetes rats combined with MI. When treated with cobalt chloride(CoCl2), blood glucose level decreased, HIF-1? expression increased and myocardial infarction size reduced in GK diabetes rats, which may provide a new insight on treatment of coronary heart disease combined with diabetes by regulating HIF-1 signal transduction system.