大鼠陈旧性心肌梗死中碎裂QRS波与心力衰竭的关系研究

The relationship between fragmented QRS complex and heart failure in rats with remote myocardial infarction

目的初步探讨大鼠陈旧性心肌梗死中碎裂QRS波与心力衰竭的关系。方法选择SD大鼠60只,按奇偶数分为心肌梗死组和假手术组,各30只。心肌梗死组通过结扎前降支冠状动脉诱导出急性心肌梗死,假手术组仅施行假手术,无冠脉结扎。采集每只大鼠术前及术后20 min、术后4周的九导联心电图,4周后超声检查评估心功能,HE及Masson染色研究心肌细胞的组织病理学,并评估纤维化的程度。结果心肌梗死组结扎20 min后,可见急性心肌损伤性改变如ST段弓背向上抬高,T波高耸,术后4周抬高的ST段基本回落,部分导联可见T波低平、病理性Q波及碎裂QRS波。术后4周心肌梗死组碎裂QRS波的发生率高于假手术组(P<0.01);与假手术组相比,心肌梗死组的左室舒张末期内径(LVEDd)、左室收缩末期内径(LVESd)增加(P<0.01),射血分数(EF)下降(P<0.01)。而对于心肌梗死组的大鼠,有碎裂QRS波大鼠LVEDd、LVESd高于无碎裂QRS波大鼠(P<0.05),EF值低于无碎裂QRS波大鼠(P<0.01)。心肌梗死组HE染色见心肌细胞数目减少,纤维增生,Masson染色可见大片蓝染区域为增生的胶原纤维,纵横交错穿插在残余的心肌细胞周围。结论碎裂QRS波在大鼠陈旧梗死中出现率高,其检出可能与前壁心肌梗死后左室扩大及射血分数降低有关。

Objective To investigate the relationship between fragmented QRS complex and heart failure in rats with remote myocardial infarction.Methods 60 healthy rats were randomly divided into two groups:the myocardial infarction group(n=30)and the sham group(n=30),the surgery of acute MI induction was performed in the myocardial infarction group through the left anterior descending coronary artery ligation,animals in the sham group were subjected to sham surgery,without coronary artery ligation.9-lead electrocardiogram were recorded simultaneously in every rats before surgery and after 20 minutes,4 weeks.The cardiac function parameters were assessed by echocardiographic assessment,4 week after surgery.Hematoxylin-eosin staining and masson′s Trichrome staining was used to study histopathology of cardiac myocytes and quantification of fibrosis was assessed.Results After 5 min ligation,acute myocardial injury changes occurred such as ST segment arch up elevation,T wave towering in the myocardial infarction group.4 weeks after the elevation of the ST segment of the basic decline,part of the lead can be seen T wave inversion,pathological Q wave or fragmentation QRS complex.The incidence of fragmented QRS complex in the myocardial infarction group was higher than that in the sham group(P<0.01).Compared with the sham group,the left ventricular end-diastolic diameter(LVEDd),left ventricular end-systolic diameter(LVESd)increased(P<0.01),and the ejection fraction(EF)decreased(P<0.01).Hematoxylin-eosin staining in the myocardial infarction group,the number of myocardial cells decreased and the fibrosis was observed.Masson′s Trichrome staining showed the large blue fibrotic area was observed in the myocardial infarction group,criss-crossing interspersed in the residual myocardial cells around.Conclusion Fragmentation QRS complex has a high incidence in rats with remote myocardial infarction in rats,which may be related to left ventricular enlargement and the decrease of ejection fraction after anterior myocardial infarction.