Increase in sudden death from coronary artery disease in young adults

Emerging Trends in Atherosclerosis: Time to Address Atherosclerosis From a Younger Age

Over the past two decades, research efforts into cardiovascular disease (CVD) have uncovered findings that fundamentally challenge our understanding of CVD, particularly atherosclerosis. Atherosclerosis was primarily attributed to the well-described abnormal lipid accumulation theory, involving plaque growth with subsequent plaque hemorrhage resulting in acute vessel thrombosis that may or may not rupture. This perspective has now evolved to encompass more complex pathways, wherein the accumulation of abnormal products of oxidation and inflammation is the most likely factor mediating atherosclerotic plaque growth. Furthermore, atherosclerosis was traditionally thought of as a disease in patients aged 40 and older. However, mounting evidence has demonstrated that significant atherosclerosis and CVD events are more prevalent in younger patients than previously realized and accelerating in incidence. With this alarming trend among younger individuals, our review sought to explore why this trend may be happening and what can be done about this developing problem.

Role of non-coding variants in cardiovascular disease

Cardiovascular diseases (CVDs) constitute one of the significant causes of death worldwide. Different pathological states are linked to CVDs, which despite interventions and treatments, still have poor prognoses. The genetic component, as a beneficial tool in the risk stratification of CVD development, plays a role in the pathogenesis of this group of diseases. The emergence of genome-wide association studies (GWAS) have led to the identification of non-coding parts associated with cardiovascular traits and disorders. Variants located in functional non-coding regions, including promoters/enhancers, introns, miRNAs and 5'/3' UTRs, account for 90% of all identified single-nucleotide polymorphisms associated with CVDs. Here, for the first time, we conducted a comprehensive review on the reported non-coding variants for different CVDs, including hypercholesterolemia, cardiomyopathies, congenital heart diseases, thoracic aortic aneurysms/dissections and coronary artery diseases. Additionally, we present the most commonly reported genes involved in each CVD. In total, 1469 non-coding variants constitute most reports on familial hypercholesterolemia, hypertrophic cardiomyopathy and dilated cardiomyopathy. The application and identification of non-coding variants are beneficial for the genetic diagnosis and better therapeutic management of CVDs.

A Case of Wellens Syndrome in a Young Adult With Intermittent Chest Pain: Understanding the Unique Pattern and Clinical Correlation

Wellens syndrome is a unique electrocardiographic (ECG) pattern usually suggestive of critical stenosis of the left anterior descending (LAD) coronary artery. Providers must recognize this pattern as it frequently occurs in symptom-free periods and represents a pre-infarction stage requiring early intervention. We present the case of a 39-year-old male with a past medical history of hypertension who was brought to the emergency department due to complaints of worsening recurrent intermittent squeezing left-sided chest pain of two months duration. Cardiac enzymes were within limits. ECG done at triage was significant for biphasic T waves in leads V2-V5 consistent with type A Wellens syndrome. The cardiology team consulted, with the patient subsequently having a percutaneous coronary intervention to the mid and proximal portion of the LAD. The patient was later discharged on the third day of admission on guideline-directed medical therapy, with plans to follow up closely with the cardiology clinic. This case highlights the significance of using the characteristics pattern of Wellens syndrome in providing critical diagnostic and prognostic value. This article aimed to promote awareness of Wellens syndrome, the clinical correlation, and the role of timely acute management.

Molecular autopsy: Twenty years of post-mortem diagnosis in sudden cardiac death

In the forensic medicine field, molecular autopsy is the post-mortem genetic analysis performed to attempt to unravel the cause of decease in cases remaining unexplained after a comprehensive forensic autopsy. This negative autopsy, classified as negative or non-conclusive, usually occurs in young population. In these cases, in which the cause of death is unascertained after a thorough autopsy, an underlying inherited arrhythmogenic syndrome is the main suspected cause of death. Next-generation sequencing allows a rapid and cost-effectives genetic analysis, identifying a rare variant classified as potentially pathogenic in up to 25% of sudden death cases in young population. The first symptom of an inherited arrhythmogenic disease may be a malignant arrhythmia, and even sudden death. Early identification of a pathogenic genetic alteration associated with an inherited arrhythmogenic syndrome may help to adopt preventive personalized measures to reduce risk of malignant arrhythmias and sudden death in the victim's relatives, at risk despite being asymptomatic. The current main challenge is a proper genetic interpretation of variants identified and useful clinical translation. The implications of this personalized translational medicine are multifaceted, requiring the dedication of a specialized team, including forensic scientists, pathologists, cardiologists, pediatric cardiologists, and geneticists.

Biomarkers for Premature Coronary Artery Disease (PCAD): A Case Control Study

Coronary artery disease (CAD) is often associated with the older generation. However, in recent years, there is an increasing trend in the prevalence of CAD among the younger population; this is known as premature CAD. Although biomarkers for CAD have been established, there are limited studies focusing on premature CAD especially among the Malay male population. Thus, the aim of this research was to compare the biomarkers between premature CAD (PCAD) and older CAD (OCAD) among Malay males. Subjects, recruited from the Universiti Kebangsaan Malaysia Medical Centre and National Heart Institution, were divided into four groups: healthy control < 45 years old; premature CAD (PCAD) < 45 years old; healthy control > 60 years old; and older CAD (OCAD) > 60 years old, with n = 30 for each group. Ten potential markers for CAD including soluble sVCAM-1, sICAM-1, interleukin-2, interleukin-6, interleukin-10, Apo-E and Apo-A1, homocysteine, CRP, and vitamin D levels were examined. Our results revealed premature CAD patients had significantly higher values (p < 0.05) of sVCAM-1, CRP, interleukin-6, and vitamin D when compared to the age-matched controls. Similarly, older CAD patients showed higher levels of sVCAM-1, CRP, and interleukin-2 when compared to their age-matched controls. After adjusting for multiple parameters, only CRP remained significant for PCAD and interleukin-2 remained significant for CAD. This indicates that premature CAD and older CAD patients showed different profiles of protein biomarkers. CRP has the potential to become a biomarker for premature CAD while interleukin-2 is a better biomarker for older CAD together with other typical panels of protein biomarkers.

Coronary Artery Disease as the Cause of Sudden Cardiac Death Among Victims < 50 Years of Age

Coronary artery disease (CAD) is the most common cause of sudden cardiac death (SCD). Atherosclerosis increases with age, but also many victims of SCD in young and middle-aged population have CAD at autopsy. The purpose of this study was to determine the characteristics and autopsy findings of SCD due to CAD among victims of SCD under the age of 50. Fingesture is a population-based study consisting of consecutive series of victims of autopsy verified SCD in Northern Finland between the years 1998 to 2017 (n = 5,869). Histological examinations were part of all autopsies and a toxicology investigation was performed if needed. Analyses included information accumulated from death certificates, medical records, autopsy data, standardized questionnaire to the closest family members of the victims of SCD and police reports of the conditions of the death. Overall, 10.4% of all SCDs occurred among victims under the age of 50 years (610 victims). Most common underlying cause of SCD among these younger SCD victims was CAD (43.6%). The prevalence of CAD as the cause of SCD became more common in young SCD victims after the age of 35 years. The mean age of ischemic SCD victims was 44±5 years and most were men (89.5%). Most victims (90.2%) had no clinical diagnosis of CAD, however 33.8% had an autopsy evidence of silent myocardial infarction. SCD occurred during physical activity in 24.1%. Three-vessel disease was detected in 44.4% of the study victims. Cardiac hypertrophy (58.3%) and myocardial fibrosis (82.6%) were also common. At least 1 cardiovascular risk factor was present in 64.7% of SCD victims. In conclusion, most SCDs among victims < 50 years of age are due to CAD.

Update on the Diagnostic Pitfalls of Autopsy and Post-Mortem Genetic Testing in Cardiomyopathies

Inherited cardiomyopathies are frequent causes of sudden cardiac death (SCD), especially in young patients. Despite at the autopsy they usually have distinctive microscopic and/or macroscopic diagnostic features, their phenotypes may be mild or ambiguous, possibly leading to misdiagnoses or missed diagnoses. In this review, the main differential diagnoses of hypertrophic cardiomyopathy (e.g., athlete's heart, idiopathic left ventricular hypertrophy), arrhythmogenic cardiomyopathy (e.g., adipositas cordis, myocarditis) and dilated cardiomyopathy (e.g., acquired forms of dilated cardiomyopathy, left ventricular noncompaction) are discussed. Moreover, the diagnostic issues in SCD victims affected by phenotype-negative hypertrophic cardiomyopathy and the relationship between myocardial bridging and hypertrophic cardiomyopathy are analyzed. Finally, the applications/limits of virtopsy and post-mortem genetic testing in this field are discussed, with particular attention to the issues related to the assessment of the significance of the genetic variants.

The Postmortem Interpretation of Cardiac Genetic Variants of Unknown Significance in Sudden Death in the Young: A Case Report and Review of the Literature

Sudden cardiac death (SCD) in adolescents and young adults is a major traumatic event for families and communities. In these cases, it is not uncommon to have a negative autopsy with structurally and histologically normal heart. Such SCD cases are generally attributed to channelopathies, which include long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia. Our understanding of the causes for SCDs has changed significantly with the advancements in molecular and genetic studies, where many mutations are now known to be associated with certain channelopathies. Postmortem analysis provides great value in informing decision-making with regard to screening tests and prophylactic measures that should be taken to prevent sudden death in first degree relatives of the decedent. As this is a rapidly advancing field, our ability to identify genetic mutations has surpassed our ability to interpret them. This led to a unique challenge in genetic testing called variants of unknown significance (VUS). VUSs present a diagnostic dilemma and uncertainty for clinicians and patients with regard to next steps. Caution should be exercised when interpreting VUSs since misinterpretation can result in mismanagement of patients and their families. A case of a young adult man with drowning as his proximate cause of death is presented in circumstances where cardiac genetic testing was indicated and undertaken. Eight VUSs in genes implicated in inheritable cardiac dysfunction were identified and the interpretation of VUSs in this scenario is discussed.

A Case of Wellens Syndrome in a 30-Year-Old Woman From Sub-Saharan Africa: A Perplexing Clinical Entity With Invaluable Lessons

With an estimated contribution of up to 6% of all acute coronary events, young adults are experiencing an escalating burden and mortality attributable to coronary artery disease (CAD) worldwide. Wellens syndrome, a preinfarction clinical entity with distinctive electrocardiographic (ECG) features and high propensity for extensive anterior wall infarctions, affects about 15% of unstable angina subpopulation. We report challenges and lessons learnt from the first ever documented case of Wellens syndrome in Tanzania. A 30-year-old female of African descent was referred to us from an upcountry zonal referral hospital for etiological determination of chest pain and expert management. Her medical history was unremarkable, and she had no apparent risk factors for CAD. She presented with a 7-day history of ongoing sharp central chest pain that was radiating to the neck and jaws and relieved momentarily by morphine. She had stable vitals with an unremarkable systemic examination; however, a 12-lead ECG revealed deeply inverted T-waves on leads V2 through V4. Based on our extensive history and physical examination we came up with a diagnosis of type B Wellens syndrome with impending anterior wall myocardial infarction. She underwent cardiac catheterization that revealed a nonthrombogenic severe subocclusive (>95%) mid left anterior descending artery stenosis. Subsequently, angioplasty was performed successfully with a resolute integrity stent, and TIMI III flow was achieved. To conclude, despite its relative frequency, physicians’ awareness of Wellens syndrome pathognomonic ECG features is of paramount importance to curb its attributable morbidity and mortality.

Sudden Cardiac Death and Copy Number Variants: What Do We Know after 10 Years of Genetic Analysis?

Over the last ten years, analysis of copy number variants has increasingly been applied to the study of arrhythmogenic pathologies associated with sudden death, mainly due to significant advances in the field of massive genetic sequencing. Nevertheless, few published reports have focused on the prevalence of copy number variants associated with sudden cardiac death. As a result, the frequency of these genetic alterations in arrhythmogenic diseases as well as their genetic interpretation and clinical translation has not been established. This review summarizes the current available data concerning copy number variants in sudden cardiac death-related diseases.

Acute myocardial infarction in a young woman: Unexpected findings of a coronary occlusion

In clinical and forensic practice, the cause of death is often attributed to acute myocardial infarction, among which the coronary atherosclerosis being the Captain of the Men of Death. However, other reasons such as coronary septic embolization with neutrophilic granulocyte myocarditis although rare, can also cause sudden unexpected death. This paper reports a case with this rare cause-a 21-year-old woman diagnosed with "acute gastroenteritis" who died 4 days later. A forensic autopsy revealed an inflammatory polypous embolic located at 1.0 cm from the left anterior descending branch (LAD) with serve neutrophilic granulocyte myocarditis, which resulted in embolic at the opening of the left main coronary artery, acute myocardial infarction and eventually leading to her death. Histopathological examination showed large amounts of neutrophilic granulocyte infiltration in the arterial layer forming the septic embolic and eventually resulting in coronary occlusion. To find the real cause of septic embolic, myocarditis, bacterial, fungal, protozoan and virus detection was performed through RT-PCR, with negative findings. Septic embolic leading coronary occlusion in left main coronary artery and LAD is rarely reported in forensic practice, we hope this report can pave the way on understanding this rare disease to make correct diagnosis in medical practice.

Heart failure and adverse heart failure outcomes among persons living with HIV in a US tertiary medical center

BACKGROUND

Persons living with HIV (PLHIV) have an increased risk of heart failure (HF). However, little is known about outcomes among PLHIV with HF. The study aim was to compare HF outcomes among PLHIV with HF versus individuals without HIV with HF.

METHODS

Our cohort included 2,308 individuals admitted with decompensated HF. We compared baseline characteristics, 30-day HF readmission, and cardiovascular (CV) and all-cause mortality. Within PLHIV, we assessed outcomes stratified between CD4 count and viral load (VL), and tested the association between traditional and HIV-specific parameters with 30-day HF readmission.

RESULTS

There were 374 (16%) PLHIV with HF. Among PLHIV, 92% were on antiretroviral therapy and 63% had a VL <200 copies/mL. Groups were similar with respect to age, sex, race/ethnicity, and CV risk factors. In follow-up, PLHIV had increased 30-day HF readmission (49% vs 32%) and CV (26% vs 13.5%) and all-cause mortality rates (38% vs 22%). Among PLHIV, cocaine use, HIV-specific parameters (CD4, VL), and coronary artery disease were predictors of 30-day HF readmission. Specifically, among PLHIV, those with detectable VL had higher 30-day HF readmission and CV mortality, whereas PLHIV with undetectable VL had a similar 30-day HF readmission rate and CV mortality to uninfected controls with HF. Similar outcomes were observed across strata of left ventricular ejection fraction and by CD4.

CONCLUSIONS

PLHIV with a low CD4 count or detectable VL have an increased 30-day HF readmission rate as well as increased CV and all-cause mortality. In contrast, PLHIV with a higher CD4 count and undetectable VL have similar HF outcomes to uninfected controls.

Manifestation of Coronary Atherosclerosis in Klang Valley, Malaysia: An Autopsy Study

Aims: The present study aimed to determine the epidemiological aspects of medico-legal autopsies and manifestation of coronary atherosclerosis.

Methods: This was a cross sectional study involving 222 cases recruited from National Institute of Forensic Medicine (NIFM) Hospital Kuala Lumpur (HKL) and Department of Forensic Medicine Hospital Sungai Buloh (HSgB) for a period of 15 months, from December 2012 to April 2014. Sociodemographic and autopsy findings, including the cause and manner of death were documented.

Results: Male and female subjects aged 18–70 years were recruited. Males contributed to 86% of the total subjects and comprised 61% of young adults. Road traffic accidents were the primary cause of death, contributing almost 50% of the subjects. One third of the cases comprised of death due to natural causes, wherein almost 75% of the subjects within this category succumbed to sudden cardiac death. Coronary artery disease (CAD) contributed to 60% of the sudden cardiac death (SCD). Single and double-vessel diseases were the most common pattern of atherosclerosis. In almost 80% of CAD cases, atherosclerosis affected the left anterior descending artery (LAD).

Conclusion: Cardiovascular diseases were the most significant natural cause of sudden death with a staggering figure of 75%. CAD was the single most commonly encountered pathology within the SCD. Most cases presented with single and double-vessel diseases, observed in all subjects, as well as the young adult population.

Association between optical coherence tomography based retinal microvasculature characteristics and myocardial infarction in young men

Incident myocardial infarction (MI) is a leading cause of adult mortality in the United States. However, because MI has a relatively low incidence in the young population, little information exists on the disease in younger adults. Because the retina has the unique quality that its vasculature is readily and noninvasively visible, the retina is frequently studied to evaluate correlations between vessels and cardiovascular diseases. In the current study, we evaluated the retinal microvasculature of patients who had experienced an MI before 50 years of age (n = 53 subjects) and age- and sex-matched patients who had not experienced an MI (n = 53 patients). We used circular optical coherence tomography (OCT) scans to image peripapillary venules and arterioles. The diameter of each vessel was measured and the respective arterial-venous ratio (AVR) was calculated. We did not detect any significant differences between MI and control subjects in retinal vessel calibre or AVR.

Influence of functional polymorphism in MIF promoter on sudden cardiac death in Chinese populations

Sudden cardiac death (SCD) is defined as an unexpected natural death without any obvious non-cardiac causes that occurs within 1 h with witnessed symptom onset or within 24 h without witnessed symptom onset. Genetic studies conducted during the past decade have markedly illuminated the genetic basis of the cardiac disorders associated with SCD. Macrophage migration inhibitory factor (MIF) is an upstream immunoregulatory cytokine associated with the pathogenesis of many inflammatory diseases including atherosclerosis and myocardial infarction. Previous studies have reported that the functional −794(CATT)_5–8 polymorphism in MIF is unrelated to sudden infant death syndrome susceptibility. However, there are no reports concerning the association between the polymorphism and adult SCD susceptibility. In the current study, we investigated the association between the −794(CATT)_5–8 polymorphism and adult SCD susceptibility using 79 adult SCD cases and 313 healthy controls. All samples were analysed using a conventional polymerase chain reaction (PCR) technique. We found that CATT₆ and 5–6 were the most common allele and genotype in both groups, respectively, while no significant association was found between the −794(CATT)_5–8 polymorphism and SCD susceptibility. We also summarized the allele frequencies of −794(CATT)_5–8 in cohorts of healthy people from different countries and found that the allele frequency distributions of the polymorphism in Chinese populations were quite different from that of American and European populations (P = 0.005, P = 0.0001, respectively), but similar to Japanese populations (P = 0.827). In conclusion, this study indicates that the −794(CATT)_5–8 polymorphism may not be associated with adult SCD susceptibility in Chinese populations. Different allele frequency distributions of the polymorphism in multiple populations may provide a useful reference for further genetic association studies.

Cardiac Channelopathies and Sudden Death: Recent Clinical and Genetic Advances

Sudden cardiac death poses a unique challenge to clinicians because it may be the only symptom of an inherited heart condition. Indeed, inherited heart diseases can cause sudden cardiac death in older and younger individuals. Two groups of familial diseases are responsible for sudden cardiac death: cardiomyopathies (mainly hypertrophic cardiomyopathy, dilated cardiomyopathy, and arrhythmogenic cardiomyopathy) and channelopathies (mainly long QT syndrome, Brugada syndrome, short QT syndrome, and catecholaminergic polymorphic ventricular tachycardia). This review focuses on cardiac channelopathies, which are characterized by lethal arrhythmias in the structurally normal heart, incomplete penetrance, and variable expressivity. Arrhythmias in these diseases result from pathogenic variants in genes encoding cardiac ion channels or associated proteins. Due to a lack of gross structural changes in the heart, channelopathies are often considered as potential causes of death in otherwise unexplained forensic autopsies. The asymptomatic nature of channelopathies is cause for concern in family members who may be carrying genetic risk factors, making the identification of these genetic factors of significant clinical importance.

Natural and Undetermined Sudden Death: Value of Post-Mortem Genetic Investigation

Background

Sudden unexplained death may be the first manifestation of an unknown inherited cardiac disease. Current genetic technologies may enable the unraveling of an etiology and the identification of relatives at risk. The aim of our study was to define the etiology of natural deaths, younger than 50 years of age, and to investigate whether genetic defects associated with cardiac diseases could provide a potential etiology for the unexplained cases.

Methods and Findings

Our cohort included a total of 789 consecutive cases (77.19% males) <50 years old (average 38.6±12.2 years old) who died suddenly from non-violent causes. A comprehensive autopsy was performed according to current forensic guidelines. During autopsy a cause of death was identified in most cases (81.1%), mainly due to cardiac alterations (56.87%). In unexplained cases, genetic analysis of the main genes associated with sudden cardiac death was performed using Next Generation Sequencing technology. Genetic analysis was performed in suspected inherited diseases (cardiomyopathy) and in unexplained death, with identification of potentially pathogenic variants in nearly 50% and 40% of samples, respectively.

Conclusions

Cardiac disease is the most important cause of sudden death, especially after the age of 40. Close to 10% of cases may remain unexplained after a complete autopsy investigation. Molecular autopsy may provide an explanation for a significant part of these unexplained cases. Identification of genetic variations enables genetic counseling and undertaking of preventive measures in relatives at risk.

Hypertrophic Cardiomyopathy as a Cause of Sudden Cardiac Death in the Young: A Meta-Analysis

BACKGROUND

Sudden cardiac death is often linked with hypertrophic cardiomyopathy in young athletes, but with a divergence of study results. We performed a meta-analysis to compare the prevalence of sudden cardiac deaths associated with hypertrophic cardiomyopathy vs sudden cardiac deaths associated with structurally normal hearts.

METHODS

A structured search of MEDLINE was conducted for studies published from 1990 through 2014. Retrospective cohort studies, patient registries, and autopsy series examining sudden cardiac death etiology in young individuals (age ≤35 years) were included. A random-effects model was applied to generate pooled summary estimates of the percentage of sudden cardiac deaths with structurally normal hearts at postmortem vs those caused by hypertrophic cardiomyopathy. Heterogeneity was assessed using I(2). Subgroup analyses were conducted based on study location, patient age groups, and population types.

RESULTS

Thirty-four studies were included, representing a combined sample of 4605 subjects. The overall pooled percentage of sudden cardiac deaths caused by hypertrophic cardiomyopathy was 10.3% (95% confidence interval [CI], 8.0%-12.6%; I(2) = 87.2%), while sudden cardiac deaths with structurally normal hearts at death were more common (P <.001) at 26.7% (95% CI, 21.0%-32.3%; I(2) = 95.3%). In nonathlete subjects, the pooled percentage of sudden cardiac deaths associated with structurally normal hearts (30.7%; 95% CI, 23.0%-38.4%; I(2) = 96.3%) were significantly more common (P <.001) than sudden cardiac death caused by hypertrophic cardiomyopathy (7.8%; 95% CI, 5.8%-9.9%; I(2) = 80.1%). Among athletes, there was no significant difference between summary estimates of hypertrophic cardiomyopathy and structurally normal hearts (P = .57), except in Europe where structurally normal hearts were more common (P = .01).

CONCLUSIONS

Hypertrophic cardiomyopathy is not a more common finding at death than structurally normal hearts in young subjects with sudden cardiac death. Increased attention should be directed toward identifying causes of death associated with a structurally normal heart in subjects with sudden cardiac death.

Rare Titin (TTN) Variants in Diseases Associated with Sudden Cardiac Death

A leading cause of death in western countries is sudden cardiac death, and can be associated with genetic disease. Next-generation sequencing has allowed thorough analysis of genes associated with this entity, including, most recently, titin. We aimed to identify potentially pathogenic genetic variants in titin. A total of 1126 samples were analyzed using a custom sequencing panel including major genes related to sudden cardiac death. Our cohort was divided into three groups: 432 cases from patients with cardiomyopathies, 130 cases from patients with channelopathies, and 564 post-mortem samples from individuals showing anatomical healthy hearts and non-conclusive causes of death after comprehensive autopsy. None of the patients included had definite pathogenic variants in the genes analyzed by our custom cardio-panel. Retrospective analysis comparing the in-house database and available public databases also was performed. We identified 554 rare variants in titin, 282 of which were novel. Seven were previously reported as pathogenic. Of these 554 variants, 493 were missense variants, 233 of which were novel. Of all variants identified, 399 were unique and 155 were identified at least twice. No definite pathogenic variants were identified in any of genes analyzed. We identified rare, mostly novel, titin variants that seem to play a potentially pathogenic role in sudden cardiac death. Additional studies should be performed to clarify the role of these variants in sudden cardiac death.

Genetics of channelopathies associated with sudden cardiac death

Recent technological advances in cardiology have resulted in new guidelines for the diagnosis, treatment and prevention of diseases. Despite these improvements, sudden death remains one of the main challenges to clinicians because the majority of diseases associated with sudden cardiac death are characterized by incomplete penetrance and variable expressivity. Hence, patients may be unaware of their illness, and physical activity can be the trigger for syncope as first symptom of the disease. Most common causes of sudden cardiac death are congenital alterations and structural heart diseases, although a significant number remain unexplained after comprehensive autopsy. In these unresolved cases, channelopathies are considered the first potential cause of death. Since all these diseases are of genetic origin, family members could be at risk, despite being asymptomatic. Genetics has also benefited from technological advances, and genetic testing has been incorporated into the sudden death field, identifying the cause in clinically affected patients, asymptomatic family members and post-mortem cases without conclusive diagnosis. This review focuses on recent advances in the genetics of channelopathies associated with sudden cardiac death.

Sudden cardiac death in young adult

Cardiovascular disease represents one of the most important public health problem in the Western countries, with sudden cardiac death (SCD) being the most common cause of death in adults under 65 years of age. The objective of the present study is to evaluate the leading causes of SCD in young adults who died suddenly in Northern Portugal between 2007 and 2012. This study included 288 cases of 20- to 45-year-old adults who died suddenly of a cardiac cause and whose forensic autopsy was performed in the North Branch of the National Institute of Legal Medicine and Forensic Sciences between 2007 and 2012. Data included the cause of death, forensic autopsy findings, previous medical history and cardiovascular risk factors. The mean age of the population was 37.36 years. Coronary artery disease (CAD) was the leading cause of death, representing 55.6 % of all cases (92.5 % of men and 7.5 % of women). Females died mostly from probable primary arrhythmia. From those who died of coronary disease, 72 (25 % of total cases) had histological evidence of a fatal acute infarction. Age, previous coronary disease, hypercholesterolemia, smoking habits and alcohol consumption seem to be associated with an increased risk of SCD by CAD. A total of 55.6 % of deaths were attributed to CAD. Prevention of cardiovascular risk factors should therefore be considered to prevent atherosclerosis in young adults.

Determining the pathogenicity of genetic variants associated with cardiac channelopathies

Advancements in genetic screening have generated massive amounts of data on genetic variation; however, a lack of clear pathogenic stratification has left most variants classified as being of unknown significance. This is a critical limitation for translating genetic data into clinical practice. Genetic screening is currently recommended in the guidelines for diagnosis and treatment of cardiac channelopathies, which are major contributors to sudden cardiac death in young people. We propose to characterize the pathogenicity of genetic variants associated with cardiac channelopathies using a stratified scoring system. The development of this system was considered by using all of the tools currently available to define pathogenicity. The use of this scoring system could help clinicians to understand the limitations of genetic associations with a disease, and help them better define the role that genetics can have in their clinical routine.

Gender differences in the prevalence, severity, and composition of coronary artery disease in the young: a study of 1635 individuals undergoing coronary CT angiography from the prospective, multinational confirm registry

OBJECTIVE

Prior studies examining coronary atherosclerosis in the young have been limited by retrospective analyses in small cohorts. We examined the relationship between cardiovascular risk factors (RFs) and prevalence and severity of coronary atherosclerosis in a large, prospective, multinational registry of consecutive young individuals undergoing coronary computerized tomographic angiography (CCTA).

METHOD AND RESULTS

Of 27 125 patients undergoing CCTA, 1635 young (<45 years) individuals without known coronary artery disease (CAD) or coronary anomalies were identified. Coronary plaque was assessed for any CAD, obstructive CAD (≥50% stenosis), and presence of calcified plaque (CP) and non-calcified plaque (NCP). Among 1635 subjects (70% men, age 38 ± 6 years), any CAD, obstructive CAD, CP, and NCP were observed in 19, 4, 5, and 8%, respectively. Compared with women, men demonstrated higher rates of any CAD (21 vs. 12%, P < 0.001), CP (6 vs. 3%, P = 0.01), and NCP (9 vs. 5%, P = 0.008), although no difference was observed for rates of obstructive CAD (5 vs. 4%, P = 0.46). Any CAD, obstructive CAD, and NCP were higher for young individuals with diabetes, hypertension, dyslipidaemia, current smoking, or family history of CAD; while only diabetes and dyslipidaemia were associated with CP. Increasing cardiovascular RFs was associated with a greater prevalence and extent and severity of CAD, with individuals with 0, 1, 2, ≥3 RFs manifesting a dose-response increase in any CAD (P < 0.001, for trend), obstructive CAD (P < 0.001, for trend), NCP (P < 0.001, for trend), and CP (P < 0.001, for trend). In multivariable analysis adjusting for sex and cardiovascular RFs, male sex was the strongest predictor for any CAD (odds ratio [OR] = 1.95, 95% confidence interval [CI] = 1.43-2.66, P < 0.001), CP (OR = 1.46, 95% CI = 1.08-1.98, P = 0.01), and NCP (OR = 1.33, 95% CI = 1.06-1.67, P = 0.01); family history of CAD was the strongest predictor for obstructive CAD (OR = 2.71, 95% CI = 1.65-4.45, P < 0.001).

CONCLUSION

Any and obstructive CAD is present in 1 in 5 and 1 in 20 young individuals, respectively, with family history associated with the greatest risk of obstructive CAD.

Negative autopsy and sudden cardiac death

Forensic medicine defines the unexplained sudden death as a death with a non-conclusive diagnosis after autopsy. Molecular diagnosis is being progressively incorporated in forensics, mainly due to improvement in genetics. New genetic technologies may help to identify the genetic cause of death, despite clinical interpretation of genetic data remains the current challenge. The identification of an inheritable defect responsible for arrhythmogenic syndromes could help to adopt preventive measures in family members, many of them asymptomatic but at risk of sudden death. This multidisciplinary translational research requires a specialized team.

No association between high-density lipoprotein levels and ventricular repolarization indexes in subjects with primary hypercholesterolemia

OBJECTIVE

Data regarding the effect of lipid parameters on repolarization are sparse. Recent data indicate that reconstituted HDL administration shortens repolarization in cardiomyocytes as well as the corrected QT (QTc) interval in human subjects. We investigated the potential association of high-density lipoprotein cholesterol (HDL-C) levels with conventional and novel electrocardiographic markers of ventricular repolarization in patients with hypercholesterolemia.

METHODS

Consecutive subjects with primary hypercholesterolemia were recruited. We recorded clinical and laboratory parameters as well as electrocardiographic indexes. With regard to ventricular repolarization, we calculated the QTc interval, the T peak-to-end (Tpe) interval, and the Tpe/QT ratio.

RESULTS

The study population consisted of 440 patients (199 men) with a median age of 56 [48-65] years. The correlation analysis (Spearman's) failed to show any association between HDL-C and any of the studied electrocardiographic parameter. Moreover, no correlation between other lipid parameters and the electrocardiograhic indexes was evident. Also, a comparison of the ventricular repolarization parameters between different HDL-C quartile groups (HDL-Q1: ≤ 1.11 mmol/L; HDL-Q2: 1.12-1.29 mmol/L; HDL-Q3: 1.30-1.53 mmol/L; HDL-Q4: ≥ 1.54 mmol/L) was performed. Specifically, the differences in QTc (p: 0.372), Tpe in leads II (p: 0.356), V2 (p: 0.372), V5 (p: 0.112), and Tpe/QT in leads II (p: 0.348), V2 (p: 0.162), V5 (p: 0.122) were not significant.

CONCLUSION

HDL-C levels are not associated with the QTc interval or indexes of repolarization dispersion in patients with primary hypercholesterolemia. The potential antiarrhythmic efficacy of HDL should be further evaluated in the setting of myocardial ischemia where dynamic changes in the heterogeneity of ventricular repolarization ensue.

[Genetics of sudden unexplained death]

Sudden unexplained death is defined by death without a conclusive diagnosis after autopsy and it is responsible for a large percentage of sudden deaths. The progressive interaction between genetics and forensics in post-mortem studies has identified inheritable alterations responsible for pathologies associated with arrhythmic sudden death. The genetic diagnosis of the deceased enables the undertaking of preventive measures in family members, many of them asymptomatic but at risk. The implications of this multidisciplinary translational medical approach are complex, requiring the dedication of a specialized team.

Pheidippides redux: reducing risk for acute cardiac events during marathon running

Prolonged strenuous exercise such as marathon running transiently increases the absolute and relative risk for sudden cardiac death. A 17-fold increase in the latter over resting baseline in previously sedentary middle-aged men is reduced due to cardioprotection from training in experienced marathon runners. Exertional rhabdomyolysis as a common occurrence during the race is accompanied by neutrophilia and elevated biomarkers of inflammation, including interleukin-6 and C-reactive protein. A hemostatic imbalance with prothrombotic effects includes in vivo platelet activation during the race. Suggesting a pathogenic role for these findings, plaque rupture due to atherothrombosis triggers acute exertional cardiac events, including sudden death, in low-risk runners as in high-risk patients such as those with diabetes mellitus. Strategies including prophylactic aspirin are considered to decrease the risk for acute cardiac events.

Lipoprotein status among urban populations in Bangladesh

OBJECTIVE

Serum lipoprotein is the most important predictor for microvascular diseases, and may be influenced by rapid urbanization. Currently available data are limited, particularly regarding age-specific lipoprotein status in urban Bangladeshi populations.

METHODS

Blood lipoprotein levels of 51,353 male and female individuals primarily residing in urban Bangladesh were analyzed. De-identified data (collected between January 2005 and December 2011) were extracted from the Clinical Biochemistry Laboratory Data Archive of International Centre for Diarrheal Disease Research, Bangladesh (icddr,b). For analyses, six age categories were created: (i) <20 years, n = 481; (ii) 20-29 years, n = 1602; (iii) 30-39 years, n = 7272; (iv) 40-49 years, n = 13,582; (v) 50-59 years, n = 15,890; and (vi) 60 years and more, n = 12,526.

RESULTS

Mean serum levels of TC, LDL, TG, LDL:HDL and TC:HDL were significantly higher among adults 30-39 years old compared to other age groups, regardless of sex. The proportion of high TC and LDL from 2005 to 2011 among individuals aged 30-39 years old varied widely (p < 0.01 for trend and all pairwise tests).

CONCLUSION

30-39 years old individuals had higher concentration of lipoprotein, which increases microvascular disease risk. Further population-based studies are needed to validate our observations in rural areas of Bangladesh.