To Explore The Influencing Factors And Forensic Significance Of Sinoatrial Node Fibrosis

Objective:Analyze the basic characteristics of sudden cardiac death and Sudden non-cardiac death,and to explore the relationship between sinoatrial node fibrosis and sudden cardiac death by observing the basic morphology of sinoatrial node,to preliminarily study the influencing factors of sinoatrial node fibrosis,to screen the characteristic proteins of sinus node fibrosis and to evaluate its relationship with sudden cardiac death.Methods:A total of 147 autopsy samples of sinoatrial node from December 2018 to August 2020 in forensic center of North Sichuan Medical College were collected and divided into sudden cardiac death group and non cardiac sudden death group according to the cause of death.Sinoatrial node tissue was extracted by traditional method,and then dehydrated and paraffin embedded.HE staining was used to observe the basic morphological changes,special staining was used to measure the content of collagen fiber,immunohistochemical staining was used to calculate the AOD value by image processing software.Pearson correlation analysis and Spearman correlation analysis were used to screen the characteristic proteins of sinoatrial node fibrosis;Multiple linear regression was used to establish the content equation of sinus node fibrosis.T test was used to evaluate the relationship between sudden cardiac death and it.Results:Sudden cardiac death was mainly in adult males.The main pathological changes of sinoatrial node were central artery stenosis,inflammation,hemorrhage and fibrosis,of which fibrosis was the first.In all age groups,the content of collagen fibers in sinoatrial node of sudden cardiac death group was higher than that of control group.Age,heart weight,abdominal wall fat thickness,epicardial adipose tissue hyperplasia and right coronary artery stenosis were positively correlated with sinus node fibrosis;Sinoatrial node fibre content=4.915+0.051*age+1.172*four of the right coronary artery stenosis+2.2*EAT hyperplasia+44.324*CAMK Ⅱ content+61.795*TRPM7 content.CaMK Ⅱ and TRPM7 were positively correlated with sinus node fibrosis.The contents of CaMK Ⅱ and TRPM7 in sudden cardiac death group were higher than those in control group.HCN4 was not associated with sinoatrial node fibrosis.The content of HCN4 in sudden cardiac death group was lower than that in control group.Conclusion:Sinoatrial node fibrosis is related to many factors(age,hyperplasia of EAT,IV degree stenosis of coronary artery lumen,CaMK,relative expression level of TRPM7),and sinoatrial node fibrosis may be one of the mechanisms of sudden cardiac death.Target proteins related to sinus node fibrosis(CaMK Ⅱ,TRPM7)are expected to be molecular markers of sudden cardiac death.