The Relationship Between Fragmented QRS Complex And Heart Failure In Rats With Remote Myocardial Infarction

Objective 12-lead fragmentation QRS wave production is closely related to the presence of myocardial fibrosis and ischemic scar.Myocardial interstitial fibrosis is one of the histological features of ventricular diastolic dysfunction.Both of them has similar pathophysiological basis.Now,there is no unified conclusion about the relationship between fragmented QRS wave and cardiac insufficiency.Therefore,this article through the establishment of animal models of acute myocardial infarction.To investigate the relationship between fragmented QRS complex and heart failure in rats with remote myocardial infarction.Methods 60 healthy healthy male 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 left ventricular end-diastolic diameter(LVEDd),left ventricular end-systolic diameter(LVESd)and ejection fraction(EF)were measured 4 weeks later to evaluate cardiac function,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,we can see acute myocardial injury changes 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 of remote myocardial infarction in rats,and its detection may be related to left ventricular enlargement and the decrease of ejection fraction after anterior myocardial infarction.