Retrospective analysis of 769 cases of sudden cardiac death from 2006 to 2015: a forensic experience in China

Lesions of the Cardiac Conduction System and Sudden Death

ABSTRACT

When a young previously healthy person dies suddenly, occasionally, the scene is noncontributory and the autopsy and drug screen are negative. In such cases, additional studies, including genetic assessment and cardiac conduction system examination, should be performed. We performed a literature search and reviewed our own material to identify possible or definite conduction system anomalies that may cause death. We identified intrinsic conduction system disease including cystic tumor of the atrioventricular node, atrioventricular node (cystic tumor of the AV node), and fibromuscular dysplasia of the atrioventricular node artery to be likely causes of death. Extrinsic causes, in which a generalized disease affects the conduction system, include tumors, autoimmune disease, infiltrative disorders, and others, are a second category of diseases that can affect the conduction system and cause atrioventricular block and sudden death.

Patients' knowledge and concerns about using the implantable cardioverter defibrillator for the primary prevention of sudden cardiac death and its correlates: A cross‐sectional study

Background and Aims

Methods

Results

Conclusion

The histopathological spectrum of myocardial inflammation in relation to circumstance of death: a retrospective cohort study in clinical and forensic autopsies

Interpreting a myocardial inflammation as causal, contributory or as of no significance at all in the cause of death can be challenging, especially in cases where other pathologic and/or medico-legal findings are also present. To further evaluate the significance of myocardial inflammation as a cause of death we performed a retrospective cohort study of forensic and clinical autopsy cases. We revised the spectrum of histological inflammatory parameters in the myocardium of 79 adult autopsy cases and related these to the reported cause of death. Myocardial slides were reviewed for the distribution and intensity of inflammatory cell infiltrations, the predominant inflammatory cell type, and the presence of inflammation-associated myocyte injury, fibrosis, edema and hemorrhage. Next, the cases were divided over three groups, based on the reported cause of death. Group 1 (n = 27) consisted of all individuals with an obvious unnatural cause of death. Group 2 (n = 29) included all individuals in which myocarditis was interpreted to be one out of more possible causes of death. Group 3 (n = 23) consisted of all individuals in which myocarditis was reported to be the only significant finding at autopsy, and no other cause of death was found. Systematic application of our histological parameters showed that only a diffuse increase of inflammatory cells could discriminate between an incidental presence of inflammation (Group 1) or a potentially significant one (Groups 2 and 3). No other histological parameter showed significant differences between the groups. Our results suggest that generally used histological parameters are often insufficient to differentiate an incidental myocarditis from a (potentially) significant one.

Postmortem detection of COL gene family variants in two aortic dissection cases

Aortic dissection (AD) usually remains undiagnosed, but its manifestation is abrupt and is associated with high morbidity and poor prognosis, leading to sudden cardiac death. Variants in COL family genes are associated with AD. In case 1, a 32-year-old Chinese man was admitted to the hospital with complaints of abdominal pain and died on the next day. In case 2, a 36-year-old Chinese woman was admitted to the hospital because of waist pain and died the next afternoon. According to autopsy findings, the cause of death in both cases was an acute cardiac tamponade, which was attributed to AD rupture. Whole-exome sequencing was performed on the blood collected from the hearts of the two deceased patients. Positive variants in COL family genes were found in both cases, without positive variants in other AD-associated genes. In case 1, a novel, likely pathogenic, missense variant was identified in COL6A1. In case 2, we identified one novel, likely pathogenic, frameshift deletion in COL23A1 and one novel, likely pathogenic, missense mutation in COL1A2. Based on these two cases, physicians should consider the role and significance of COL family gene mutations in AD in young patients. Furthermore, molecular anatomy is clearly necessary and significant in cases of sudden cardiac death attributed to AD, particularly in younger individuals.

Retrospective Analysis of Sudden Cardiac Deaths in a 10-Year Autopsy Series in the City of Isparta in Turkey

Sudden cardiac death (SCD) is an important public health problem that accounts for approximately 15% to 20% of global deaths. Our retrospective study aimed to analyze etiological distribution and epidemiological data of 128 cases with SCD as death cause based on autopsies between 2010 and 2019. The mean age of SCD cases was 57.09, with the highest incidence in older than 60 years (43.8%). Male/female ratio was 4.5:1, peaking with 9.2:1 in the 41- to 60-year age group. Deaths occurred mostly at home (41.4%). Coronary atherosclerotic heart disease (CAD) was main SCD cause (65.6%) with cardiac tamponade (10.9%), unexplained SCD (8.6%), and hypertrophic cardiomyopathy (7.8%) after it. A total of 71.2% of CAD cases had coronary artery stenosis of greater than 75% and 92.9% had atherosclerotic degeneration in the left anterior descending artery. Based on the body mass index-based normal heart weights table, 91.7% of CAD cases had cardiomegaly. This study showed CAD, cardiomegaly, and high body mass index concurrence as a very important SCD risk. Because SCD incidence increases in older than 40 years, determining risk groups through regular medical examinations and inspections, older than 30 years would provide implementation of preventive measures. Some cardiac diseases causing sudden death are undetectable despite detailed autopsy and histopathological examinations. Including postmortem cardiogenetic analysis among routine techniques in sudden deaths would lower sudden unexplained death diagnosis rates.

Sudden Death from Ischemic Heart Disease While Driving: Cardiac Pathology, Clinical Characteristics, and Countermeasures

Background

Sudden death from ischemic heart disease while driving is an important cause of traffic accidents. This study discusses causes of traffic accidents in relation to risk factors for acute myocardial infarction such as hypertension and overwork and provides references for the early prevention and regulation of drivers’ health conditions.

Material/Methods

Data on 21 cases of sudden death by ischemic heart disease while driving from January 2015 to December 2019 were collected. Age, symptoms, and cardiac pathological changes of patients were summarized by systematic anatomical and medical history data.

Results

Patients were 21 men with an average age of 47±7.27 years (most aged 40 to 60 years), and the average weight of their hearts was 439.45±76.3 g. Twelve patients had a history of hypertension, 8 had previous myocardial infarction, and 4 had fatty liver. All had at least 1 severe narrowing of a major coronary artery. Twelve patients died within a short period; 9 died more than 12 h after myocardial infarction onset. Ten patients had worked more than 80 h of overtime per month, 4 patients, more than 45 h, and 7 patients, less than 45 h.

Conclusions

Regular physical examination and information about ischemic heart disease should be emphasized for men aged 40 to 60 years who drive frequently, especially for those with hypertension, overwork, or previous myocardial infarction. Incorporating objective evaluation criteria for the severity of ischemic heart disease and overwork into health condition-related driving regulations is needed.

Retrospective analysis of 172 cases of custodial deaths in China between 1999 and 2016: forensic experience in China

Custodial deaths refer to the death of an individual who is in prison, a detention center, or a police station. The present study aims to retrospectively analyze cases of custodial deaths examined at Tongji Medico Legal Expertise Center in Hubei (TMECH). A total of 172 out of 5853 cases were screened at TMECH from January 1999 to December 2016. Male preponderance was observed in 172 cases (male-female ratio: 5:1). Natural deaths accounted for the majority (70.93%), followed by suicide (16.28%), accidents (3.49%), homicides (4.65%), and undetermined causes (4.65%). The most common natural cause was cardiovascular disease. Custodial deaths occurred more frequently in prisons and detention houses than in police cells (63%, 63%, and 46%, respectively). Among the 172 cases, 105 deaths occurred after resuscitation failure despite the individual being sent to the hospital. The average age across cases was 36.3 years, and 90% of the deceased were aged under 50 years. Since there is no officially reported data regarding the prevalence of causes and manners of custodial deaths in China, our analysis contributes to enhancing the understanding of such deaths in central China and serves as a reference for law enforcement to develop a prevention program to reduce incidents of mortality in custody.

A common indel polymorphism of the Desmoglein-2 (DSG2) is associated with sudden cardiac death in Chinese populations

Sudden cardiac death (SCD) is referred to as sudden and unexpected death caused by cardiovascular diseases, in which a person preexisted heart disease or not. Compelling evidence indicates that SCD etiology have been predominantly affected by host genetic factors. However, how genetic variants play roles in the inherited risk component of SCD are still largely unknown. It has been reported that Desmoglein-2 (DSG2) mutations might be related to sudden death. In the present study, we used a candidate gene approach to investigate the associations between rs397729601 (a 2-base pair indel polymorphism) mapping to the 3'UTR of DSG2 with the risk of SCD. It is shown by logistic regression analysis that the risk of SCD has been significantly increased by the deletion allele of rs397729601 [odds ratio (OR)=1.51; 95% confidence interval (CI)=1.12-2.05; P=0.00559]. Additional genotype-phenotype analysis was performed to evaluate the mRNA level, revealing that human myocardium tissues with the deletion allele showed higher expression of DSG2. Dual luciferase activity analysis was conducted in an in vitro reporter gene system, suggesting that DSG2 expression could be regulated by rs397729601 which interrupted the binding of miR-933-3p with DSG2. We concluded that rs397729601 may affect the expression of DSG2 through miR-933-3p regulation, contributing to SCD susceptibility. Thus, rs397729601 may be used as a potential marker for molecular diagnosis and genetic counseling of SCD. Our findings need to be validated through replication and further functional studies.

Cystic tumour of the atrioventricular node: case report and literature review

Cystic tumour of the atrioventricular node is the smallest tumour that can cause sudden cardiac death. This lesion arises from foregut endodermal rests which become enfolded into the heart during embryogenesis. Typically causing heart block, the tumour can cause sudden death despite pacemaker placement. Sudden death in such cases can be caused by arrhythmogenic ectopic foci arising from impaired electrical impulse propagation through the abnormal atrioventricular junction conducting tissue.

Functional reclassification of variants of uncertain significance in the HCN4 gene identified in sudden unexpected death

The HCN4 gene encodes a subunit of the hyperpolarization-activated cyclic nucleotide-gated channel, type 4 that is essential for the proper generation of pacemaker potentials in the sinoatrial node. The HCN4 gene is often present in targeted genetic testing panels for various cardiac conduction system disorders and there are several reports of HCN4 variants associated with conduction disorders. Here, we report the in vitro functional characterization of four rare variants of uncertain significance (VUS) in HCN4, identified through testing a cohort of 296 sudden unexpected natural deaths. The variants are all missense alterations, leading to single amino acid changes: p.E66Q in the N-terminus, p.D546N in the C-linker domain, and both p.S935Y and p.R1044Q in the C-terminus distal to the CNBD. We also identified a likely benign variant, p. P1063T, which has a high minor allele frequency in the gnomAD, which is utilized here as a negative control. Three of the HCN4 VUS (p.E66Q, p.S935Y, and p.R1044Q) had electrophysiological characteristics similar to the wild-type channel, suggesting that these variants are benign. In contrast, the p.D546N variant in the C-linker domain exhibited a larger current density, slower activation, and was unresponsive to cyclic adenosine monophosphate (cAMP) compared to wild-type. With functional assays, we reclassified three rare HCN4 VUS to likely benign variants, eliminating the necessity for costly and time-consuming further study. Our studies also provide a new lead to investigate how a VUS located in the C-linker connecting the pore to the cAMP binding domain may affect the channel open state probability and cAMP response.

Predictors, Burden, and the Impact of Arrhythmia on Patients Admitted for Acute Myocarditis

A significant proportion of patients with acute myocarditis experience sudden cardiac death presumably due to cardiac arrhythmia. In this study, we explore the burden, the predictors of arrhythmia in acute myocarditis and the association between arrhythmias and adverse in-hospital outcomes. After evaluating the frequency of various tachyarrhythmias and bradyarrhythmia in myocarditis population, we built a logistic model to determine the independent predictors of arrhythmias in myocarditis and a 1:1 propensity-matched analysis to examine the impact of arrhythmias. Overall, cardiac arrhythmias were identified in 33.71% of the hospitalized myocarditis cases. Ventricular tachycardia and atrial fibrillation were most common arrhythmias. There were increased odds of in-hospital mortality, cardiogenic shock, use of mechanical circulatory support, pacemaker implantation, and nonroutine hospital discharges in the arrhythmia cohorts. Length of stay and cost of hospitalization were also significantly higher. A significant proportion of patients with myocarditis have cardiac arrhythmias. As the occurrence of arrhythmias in myocarditis is associated with worse outcomes, it may be important to risk stratify patient to identify those who will benefit from early intervention.

RPS3A positively regulates the mitochondrial function of human periaortic adipose tissue and is associated with coronary artery diseases

Pericardial adipose tissue, which comprises both epicardial adipose tissue (EAT) and paracardial adipose tissue (PAT), has recently been recognized as a novel factor in the pathophysiology of cardiovascular diseases, especially coronary artery disease (CAD). The goal of this study was to evaluate differences in the brown-like characteristic and proteome among human EAT, PAT, and subcutaneous adipose tissue (SAT) to identify candidate molecules causing CAD. Uncoupling protein 1 (UCP-1) and other brown-related proteins were highly expressed in pericardial adipose tissue but was weakly expressed in SAT from the same non-CAD patient. Moreover, pericardial adipose tissues displayed a higher thermogenesis than SAT. However, brown-related genes were lower in CAD pericardial fat. Remarkably, there were lower levels of metabolic enzymes involved in glycolysis, tricarboxylic acid cycle, and fatty acid metabolism in pericardial adipose tissues of CAD. EAT is an organ adjacent to aortic root without anatomy barriers, which differs from PAT. We found that the expression of ribosomal protein S3A (RPS3A) was decreased in human EAT as well as in mouse perivascular adipose tissue (PVAT). Knockdown of RPS3A significantly inhibited adipocyte differentiation in preadipocytes and impaired the function of mitochondria in mature adipocytes. Moreover, RPS3A knockdown in mouse periaortic adipose tissue impaired browning of PVAT, accelerated vascular inflammation, and atherosclerosis progression. Mechanistically, RPS3A can migrate to the mitochondria to maintain the function of brown adipocytes. These findings provide compelling evidence that RPS3A was a key factor for modulating the brown fat-specific gene UCP-1 and carbon metabolic enzymes in EAT for preventing CAD.