Sudden Arrhythmic Death Syndrome Research Articles

Acquired long QT interval syndrome as a predictor of sudden cardiac death: Causes, diagnostic criteria, and management strategy

Despite medical advances in diagnosis and treatment, cardiovascular disease remains the leading cause of death worldwide. Sudden cardiac death, an extreme and irreversible outcome of cardiac arrest, is observed in 50% of cases and is often the first suddenly detected pathology. Long QT syndrome is a variant of electrical heart disease resulting from both congenital and acquired dysfunction and/or regulation of cardiomyocyte ion channels, accompanied by impaired depolarization and repolarization of the ventricular myocardium and characterized by QT prolongation and T abnormalities on the electrocardiogram, clinically accompanied by syncope, bidirectional spindle ventricular tachycardia of the “pirouette” type (torsade de pointes), associated with a high risk of sudden cardiac death or sudden arrhythmic death syndrome. Effective management of these patients requires an individualized approach: careful examination, calculation of corrected QT, determination of typology (hereditary or acquired syndrome), risk assessment using the Tisdale scale, and selection of optimal therapy. Treatment should be comprehensive and include pharmacological (beta-adrenergic blockers, correction of electrolyte balance) and surgical (implantable cardioverter-defibrillator and left-sided thoracic sympathetic denervation of the heart), lifestyle (avoidance of drugs that contribute to prolongation of the QT interval, avoidance of specific arrhythmia triggers (active swimming, exposure to loud noises)) and regular consultation with a cardiologist. Early diagnosis and a comprehensive approach are key to successful prevention of sudden cardiac death in patients with Long QT syndrome.

Implications of age and sex on the diagnostic yield of sudden arrhythmic death syndrome

Abstract Introduction Sudden arrhythmic death syndrome (SADS) refers to an unexplained sudden death with a negative autopsy. An inherited cardiac condition (ICC) may be diagnosed through familial clinical evaluation (FE) or post-mortem genetic testing (molecular autopsy [MA]) or both. We aimed to investigate the impact of age and sex of SADS decedents on the diagnostic yield and aetiology to facilitate a targeted approach to management. Methods Consecutive referrals to a single centre for FE only, MA only or both, following a SADS death were included. First-degree family members underwent comprehensive FE. A panel of 36 cardiac genes was sequenced for MA. A post-mortem diagnosis could be obtained by either FE, MA or both. A Bayesian framework for analysis was performed to identify associations. Results Seven-hundred-and-sixty SADS decedents (66% male; mean age 31±12 years) were investigated. The overall diagnostic yield for an ICC was 37% (32-42%) and 9% (6-12%) for FE and MA cohorts, respectively. In a subset where both MA and FE were performed the diagnostic yield was 45% (38-61%). For each year increase in age, the relative risk of an FE diagnosis of long QT syndrome (LQTS) or Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) versus remaining unexplained declined by 5.6% (RR 0.94 [0.91-0.98]) and by 11% (RR 0.89 [0.81-0.97]), respectively. Females were more likely to have a diagnosis compared with males by both FE (40% [34-45%] vs 36% [31-41%]) and MA (15% [10-21%] vs 6% [3-8%]). Females (8.1% [4.1-13.4%)], were more likely to be diagnosed with LQTS than males (1.2% [0.2-2.7%]) in the MA cohort. Conclusions After a SADS death, the diagnostic yield of comprehensive FE, MA or both in an expert setting can be up to 45%. Younger age of death is associated with greater likelihood of LQTS and CPVT diagnosis with the highest yield in children and adolescents. Female sex in SADS decedents is associated with a higher yield of LQTS in MA. These data highlight the relative utility of FE and MA depending on age and sex for determining underlying diagnoses following SADS deaths.

Insights into the aetiology and temporal trends in cardiac mortality in the young: a 21-year review of national and registry data in the united kingdom

Abstract Background An accurate representation of the incidence and aetiology of cardiac and sudden cardiac death (SCD) is vital for healthcare policymakers to effectively allocate resources for preventative strategies. Purpose We aimed to report on the incidence and causes of cardiac and SCD among individuals under 35-years-old in England and Wales for 21 years (2001-2021), with a focus on identifying any temporal trends. Methods Annual mortality data from the Office for National Statistics (ONS) pertaining to cardiovascular (CV) and possible CV deaths in individuals under 35-years-old were analyzed using International Classification of Diseases-10 codes. Deaths were categorized into four-classes: A1- definitive cardiac deaths without identifiable structural heart disease (consistent with sudden arrhythmic death syndrome, SADS); A2- definitive cardiac deaths with identified structural heart disease; A3- definitive cardiac deaths with indeterminate cause; and B- potential cardiac deaths. Incidence rates were computed based on annual ONS census data. Additionally, insights were gleaned from the Cardiac Risk in the Young Centre for Cardiac Pathology (CRYCCP) nationwide registry. Results The mean annual number of definitive cardiac deaths (classes A1+A2+A3) was 414 (SD 27.4), resulting in an incidence of young cardiac and SCD of 1.68/100,000 individuals/year. Ischaemic heart disease (28.4%), cardiomyopathies (25.9%), and SADS (21.8%) were the most prevalent cardiac conditions. Cardiomyopathies and SADS related mortality peaked in the 10-to-19 age group, while ischaemic heart disease peaked in the 30-to-35 age group. A mean of 573 (SD 76.6) possible cardiac deaths (class B) occurred, these primarily included ill-defined causes (33.5%), epilepsy (32.4%), sudden infant death syndrome (24.2%), and drowning (7%). Definitive and possible cardiac deaths showed a male preponderance (male to female ratios: 2.3:1 and 1.6:1, respectively). A declining trend in cardiac mortality was observed with a 1.3% (95%CI: 1.0%-1.7%) incidence rate reduction/year (p<0.001). This was associated with a 2.5% annual incidence rate reduction for deaths attributed to structural heart disease (p<0.001), but an 8.5% annual incidence rate increase for deaths attributed to SADS (p<0.001). These trends corelated with increasing numbers of deaths referred to the CRYCCP where an expert cardiac pathologist diagnosed SADS in over 52% of cases. Conclusions Over 21 years in England and Wales, national datasets suggest the incidence of young cardiac and SCD is 1.68/100,000/year, with a small but appreciable declining mortality trend. The rise in SADS rates and contemporaneous decline in deaths attributed to structural heart disease may signify increased awareness and accessibility to expert cardiac pathologists. Ensuring accurate mortality coding is crucial for thoroughly assessing first-degree family members in cases of suspected inherited cardiac conditions.

Cardiovascular etiologies and risk factors of survival outcomes after resuscitation for out-of-hospital cardiac arrest: data from the KoCARC registry

Abstract Background The outcomes and characteristics of out-of-hospital cardiac arrest (OHCA) vary across geographic regions. The etiologies and prognoses of OHCA in Asian populations remain less established. This study aimed to investigate the etiologies and clinical characteristics of patients successfully resuscitated after OHCA and identify predictors of survival outcomes. Methods Data were extracted from a South Korean multicenter prospective registry of OHCA that included 64 tertiary hospitals from 2015 to 2018 (n=7577). The primary outcome was in-hospital mortality, and secondary outcome was the grade-1 cerebral performance category (CPC) score at discharge. Results Of the 7577 patients, 2066 achieved return of spontaneous circulation (ROSC) and were hospitalized and 915 (44·2%) presented with ventricular arrhythmia (VA) as their initial rhythm or on admission. The leading cause was obstructive coronary artery disease (n=413; 20·0%). Sudden unexplained death syndrome (SUDS) accounted for 67·5% of survivors, which were significantly lower with VA (82·7% vs. 48·3%, p<0.001). VA was an independent predictor of in-hospital mortality (adjusted hazard ratio [aHR] 0·72, 95% confidence interval 0·60–0·87) and the grade-1 CPC score at discharge (aHR 3·63, 95% CI 2·56–5·15). Other predictors of the primary outcome included age, ROSC on arrival, total arrest time, alertness on admission, extracorporeal membrane oxygenation use, targeted temperature management, implantable cardioverter defibrillator use, and coronary vasospasm. Conclusions SUDS was common in patients with ROSC after OHCA and thus needs to be evaluated comprehensively. VA was independently associated with favorable survival outcomes at discharge. Further management may improve clinical outcomes in patients with OHCA, particularly those with VA.

Trends in Sudden Unexpected Deaths in an Australian Population: Impact of the COVID-19 Pandemic

SARS-CoV-2 infection is associated with increased cardiovascular (CV) morbidity and mortality, manifesting as increased adverse outcomes in the first 30 days, extending to 12 months. This study aimed to investigate trends in sudden unexpected deaths between 2018 and 2022, with a focus on CV deaths. A retrospective analysis was performed on autopsy reports (n=9,330) obtained from New South Wales Coroners Court, Australia, specifically targeting cases of unexplained deaths that occurred between 2018 and 2022. Statistical analysis was conducted using chi-square tests and a post hoc analysis with Bonferroni correction, as well as analysis of variance with multiple comparisons. There were 349 (18.3%) CV deaths in 2018, 346 (18.0%) in 2019, 338 (17.5%) in 2020, 395 (21.9%) in 2021, and (23.4%) 413 in 2022 (p=0.0002). Among CV deaths, the number of deaths from sudden arrhythmic death syndrome were 25 (7.2%) in 2018, 26 (7.5%) in 2019, 18 (5.3%) in 2020, 52 (13.2%) in 2021, and 80 (19.4%) in 2022 (p=0.0001). Atherosclerosis was the most common cause of death among all CV categories; there were 196 (56.2%) atherosclerosis deaths in 2018, 207 (59.8%) in 2019, 192 (56.8%) in 2020, 221 (56.0%) in 2021, and 197 (47.7%) in 2022 (p=0.43). The average age of death from sudden arrhythmic death syndrome (42.8±19.1 years) across 2018-2022 was younger than atherosclerosis (56.2±12.4 years) and total groups (53.1±15.1 years) (p<0.001). Males comprised 76% of all CV deaths from 2018 to 2022 (p<0.0001). Compared with pre-pandemic data, a noteworthy increase in CV deaths was observed in occurrence with the escalation in COVID-19 cases in Australia. This may be attributed to direct or indirect factors, such as lifestyle modifications, disrupted access to routine cardiac care, or COVID-19 infection-triggered CV deaths.

Sudden Intrauterine Unexplained Death (SIUD) and Oxidative Stress: Placental Immunohistochemical Markers.

Intrauterine fetal death and perinatal death represent one of the most relevant medical scientific problems since, in many cases, even after extensive investigation, the causes remain unknown. The considerable increase in medical legal litigation in the obstetrical field that has witnessed in recent years, especially in cases of stillborn births, has simultaneously involved the figure of the forensic pathologist in scientific research aimed at clarifying the pathophysiological processes underlying stillbirth. our study aims to analyze cases of sudden intrauterine unexplained death syndrome (SIUD) to evaluate the role of oxidative stress in the complex pathogenetic process of stillbirth. In particular, the immunohistochemical expression of specific oxidative stress markers (NOX2, NT, iNOS, 8-HODG, IL-6) was evaluated in tissue samples of placentas of SIUDs belonging to the extensive case series (20 cases), collected from autopsy cases of the University of Ferrara and Politecnica delle Marche between 2017 and 2023. The study demonstrated the involvement of oxidative stress in intrauterine fetal deaths in the placenta of the cases examined. In SIUD, the most expressed oxidative stress markers were NOX2 and 8-HODG. The study contributes to investigating the role of oxidative stress in modulating different pathways in unexplained intrauterine fetal death (SIUD) tissues.

Genetic and clinical characteristics of catecholaminergic polymorphic ventricular tachycardia in a Taiwanese nationwide cohort

BackgroundCatecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare and lethal arrhythmia. Ryanodine receptor 2 (RYR2) mutation accounts for ∼60% of CPVT patients which is inherited in an autosomal dominant pattern. ObjectiveThis study aimed to identify CPVT-related mutations and clinical characteristics among Taiwanese CPVT patients and compare to other cohorts worldwide. MethodsClinical and genetic data were obtained from the Sudden Arrhythmia Death Syndrome Registry in Taiwan (SADS-TW). Forty clinically diagnosed Taiwanese CPVT patients were included. ResultsThis is the first nationwide CPVT cohort in Taiwan. Among the 29 Taiwanese patients with CPVT-related gene mutations, 55% had RYR2 mutations, a rate similar to other ethnicities. Three out of 12 RYR2 variants were unreported. Exercise-induced symptoms including syncope and cardiac arrest were more frequent in East Asian cohorts (Taiwanese 79%, Japanese 91%), compared to Caucasian cohorts (59%) (p = 0.002). ConclusionThe discovery of diverse RYR2 mutations in the Taiwanese CVPT population demonstrates the importance of genetic testing in different ethnicities.

Proarrhythmic drugs, drug levels, and polypharmacy in victims of sudden arrhythmic death syndrome: An autopsy-based study from Denmark

BackgroundSudden arrhythmic death syndrome (SADS), characterized by an unknown or inconclusive cause of death at autopsy together with a negative or nonlethal toxicology screening result, is the most common cause of sudden cardiac death in victims younger than 35 years. The complete causality of SADS remains unclear, with drugs being a potential risk factor. ObjectiveThis study aimed to describe the toxicologic profiles of SADS victims, focusing on proarrhythmic drugs, drug levels, and polypharmacy. MethodsAll deaths in Denmark of those aged 1–35 years in 2000–2019 and 36–49 years in 2007–2019 were examined through death certificates, national registries, and autopsy reports with toxicology screenings. We investigated all sudden unexpected death victims with an autopsy performed, including negative or nonlethal drug findings, where cause of death was unknown or inconclusive (SADS). ResultsWe identified 477 SADS victims; 313 (66%) had a positive toxicology screening result (adjudicated nonlethal), with an average of 2.8 drugs per case. More than half of the SADS victims with a positive toxicology screening result had QT-prolonging or brugadogenic drugs present. Polypharmacy was present in 66%, psychotropic polypharmacy in 37%, and QT-prolonging polypharmacy in 22%, with the most frequent overall and QT-prolonging drug combination being an antipsychotic and a psychoanaleptic drug. QT-prolonging drugs were more often present at suprapharmacologic levels than non–QT-prolonging drugs. ConclusionThe majority of the SADS population had a positive toxicology screening result, with a notably large proportion having proarrhythmic drugs and polypharmacy. This highlights the need for future focus on drugs as a risk factor for SADS.

Diversity of ICD-10 coding for sudden arrhythmic death syndrome is likely to create a spurious rise in cases under new ICD-11 nomenclature

Diversity of ICD-10 coding for sudden arrhythmic death syndrome is likely to create a spurious rise in cases under new ICD-11 nomenclature

Ethnicity and sudden cardiac death in athletes: insights from a large United Kingdom registry.

The relationship between ethnicity and causes of sudden cardiac death (SCD) in athletes is poorly understood. To investigate aetiology of SCD among different ethnicities in a large cohort of athletes. Between 1994 and November 2022, 7880 cases of SCD were consecutively referred from all over the United Kingdom to our national cardiac pathology centre; 848 (11%) were athletes. All cases underwent detailed autopsy evaluation by expert cardiac pathologists. Clinical information was obtained from referring coroners. Most of athletes were white (n = 758; 89%). Black and Asian athletes were in number of 51 (6%) and 39 (5%), respectively. A structurally normal heart, indicative of sudden arrhythmic death syndrome (SADS) was the most common autopsy finding (n = 385; 45%), followed by myocardial diseases (n = 275; 32%), atherosclerotic coronary artery disease (CAD) (n = 58; 7%), and coronary artery anomalies (n = 29; 3%). In most of cases, death occurred during exercise (n = 737; 87%). Arrhythmogenic cardiomyopathy (ACM) was more common in black (n = 13; 25%) than in white (n = 109; 14%) and Asian (n = 3; 8%) athletes (P = 0.03 between black and white athletes; P = 0.04 between black and Asian athletes); in contrast, CAD was more common in Asians (n = 6; 15% vs. n = 51; 7% in whites vs. n = 1; 2%; in blacks, P = 0.02 between Asian and black athletes). Among white athletes, ACM was more common in individuals who died during exercise than in the ones who died at rest (P = 0.005). Such a difference was not observed in Asian and black athletes. In Asian athletes, CAD was the diagnosis at autopsy in 18% of individuals who died during exercise and in none of individuals who died at rest. A structurally normal heart at autopsy and myocardial diseases are the most common findings in athletes who died suddenly. While ACM is more common in black athletes, atherosclerotic CAD is more common in Asian athletes, with a strong association with exercise-induced SCD. ACM appears to be a driver of exercise-induced SCD in white athletes, however this is not the case in black and Asian athletes.

Incidence of quadricuspid pulmonary valves at postmortem examination

Quadricuspid pulmonic valve is a rare congenital abnormality and because of its difficult non-invasive assessment, it is usually discovered incidentally at autopsies (reported prevalence in post-mortem specimens ranges from 1 in 400 to 1 in 2000). Unlike a bicuspid pulmonary valve, it rarely presents with clinical complications, such as valvular insufficiency or stenosis. Abnormal function is rarely reported in cases that are not associated with other congenital heart disease. With increased sophistication of imaging coincidental quadricuspid valves autopsy studies are important to understand the anatomical consequences of this finding. Our case series identified 21 QPV cases from the Victorian Institute of Forensic Medicine, Melbourne and St George's University of London, Department of Cardiovascular Pathology. Cases were identified through local database searches and review of autopsy/cardiac examination reports over a 20-year period. Available photographs were also systematically examined. Fifteen cases had causes of death with no direct causality to cardiac valvular pathology alone. Six cases were considered unascertained or similar (sudden arrhythmic death syndrome and sudden unexpected death in epilepsy). The presence of QPV in these instances were uncertain but thought to be unlikely contributory to death, due to the absence of pulmonary valvular complications.

Seasonal Variation in Sudden Cardiac Death: Insights from a Large United Kingdom Registry

BackgroundSudden cardiac death (SCD) is relatively common and may occur in apparently healthy individuals. The role of seasonal variation as a risk factor for SCD is poorly understood. The aim of this study was to investigate whether SCD exhibits a predilection for specific seasons. MethodsWe reviewed a database of 4751 cases of SCD (mean age 38 ± 17 years) referred to our Center for Cardiac Pathology at St George’s University of London between 2000 and 2018. Clinical information was obtained from referring coroners who were asked to complete a detailed questionnaire. All cases underwent macroscopic and histological evaluation of the heart, by expert cardiac pathologists. ResultsSCD was more common during winter (26%) and rarer during summer (24%), p = 0.161. Significant seasonal variation was not observed among cases of sudden arrhythmic death syndrome (SADS, 2910 cases) in which the heart is structurally normal. In contrast, a significant difference in seasonal distribution among decedents exhibiting cardiac structural abnormalities at the post-mortem examination (n = 1841) was observed. In this subgroup, SCDs occurred more frequently during winter (27 %) compared to summer (22%) (p = 0.007). In cases diagnosed with a myocardial disease (n = 1399), SCD was most common during the winter (27%) and least common during the summer (22%) (p = 0.027). ConclusionsWhile SADS occurs throughout the year with no seasonal variation, SCD due to structural heart disease appears to be more common during the winter. Bio-meteorological factors may be potential triggers of SCD in individuals with an underlying structural cardiac abnormality.

Diabetes Epidemic- Heart Health &amp; Homoeopathy

The famous singer KK died of heart attack, another TV actor died of heart attack. All these deaths are relatively at a younger age. In recent times, there has been a rise of such cases of sudden heart attacks &amp; it is essential to understand the cause. There is a clear link between uncontrolled sugar levels &amp; neuropathy. This phenomenon leads to masking of heart attack symptoms thus resulting in unexpected deaths. These are actually sudden cardiac arrest or arrhythmic death syndrome [3].

Epidemiology of Sudden Unexplained Death Syndrome among Southeast Asian Labor in Taiwan

Epidemiology of Sudden Unexplained Death Syndrome among Southeast Asian Labor in Taiwan

Editorial introductions.

Editorial introductions.

National sudden cardiac death autopsy database highlighting sudden arrhythmic death and cardiomyopathies, applying diagnostic criteria and expanding the concept of the molecular autopsy

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): Cardiac Risk in the Young Background Sudden cardiac death (SCD) is defined as natural unexpected death in witnessed cases occurring &amp;lt;1 hour and in unwitnessed cases as last seen alive &amp;lt;24hours. SCD due to ischaemic heart disease (IHD) is frequent in older age groups, in younger people genetic cardiac causes including channelopathies and cardiomyopathies are more frequent. Purpose To present the causes of SCD from a large pathology registry. Methods Cases were examined macroscopically and microscopically by two expert cardiac pathologists. Criteria used are presented in figure 1. Results The hearts from 7214 SCD cases were examined between 1994-2021. Sudden arrhythmic death syndrome (SADS), a morphologically normal heart, which can be underlain by the channelopathies, is most common (3821, 53%) followed by the cardiomyopathies (1558, 22%), then IHD (670, 9%). Valve disease (225, 3%), congenital heart disease (213, 3%) and myocarditis/sarcoidosis (206, 3%) are the next most common. Hypertensive heart disease (185, 3%), aortic disease (129, 2%), vascular disease (97, 1%) and conduction disease (40, 1%) are smaller proportions (figure 2). Discussion This is the largest SCD cohort with autopsy findings ever reported from one country. SADS and cardiomyopathies predominate. This study highlights the importance of the autopsy in SCD which is a significant public health concern in all age groups. Knowing the true incidence in our population will improve risk stratification and develop preventative strategies for family members. There is now a national pilot study integrating molecular autopsy into the assessment of SCD victims.

Post-mortem genetic testing in sudden cardiac death and genetic screening of relatives at risk: lessons learned from a Czech pilot multidisciplinary study

Sudden cardiac death (SCD) might have an inherited cardiac condition background. Genetic testing supports post-mortem diagnosis and screening of relatives at risk. Our aim is to determine the feasibility of a Czech national collaboration group and to establish the clinical importance of molecular autopsy and family screening. From 2016 to 2021, we have evaluated 100 unrelated SCD cases (71.0% males, age: 33.3 (12.8) years). Genetic testing was performed by next-generation sequencing utilizing a panel of 100 genes related to inherited cardiac/aortic conditions and/or whole exome sequencing. According to autopsy, cases were divided into cardiomyopathies, sudden arrhythmic death syndrome, sudden unexplained death syndrome, and sudden aortic death. We identified pathogenic/likely pathogenic variants following ACMG/AMP recommendations in 22/100 (22.0%) of cases. Since poor DNA quality, we have performed indirect DNA testing in affected relatives or in healthy parents reaching a diagnostic genetic yield of 11/24 (45.8%) and 1/10 (10.0%), respectively. Cardiological and genetic screening disclose 83/301 (27.6%) relatives at risk of SCD. Genetic testing in affected relatives as starting material leads to a high diagnostic yield offering a valuable alternative when suitable material is not available. This is the first multidisciplinary/multicenter molecular autopsy study in the Czech Republic which supports the establishment of this type of diagnostic tests. A central coordinator and proper communication among centers are crucial for the success of a collaboration at a national level.

Sudden arrhythmic death and cardiomyopathy are important causes of sudden cardiac death in the UK: results from a national coronial autopsy database.

Sudden cardiac death (SCD) is defined as natural unexpected death in witnessed cases occurring < 1h and in unwitnessed cases as last seen alive < 24h. SCD due to ischaemic heart disease (IHD) is frequent in older age groups; in younger people genetic cardiac causes, including channelopathies and cardiomyopathies, are more frequent. This study aimed to present the causes of SCD from a large specialist pathology registry. Cases were examined macroscopically and microscopically by two expert cardiac pathologists. The hearts from 7214 SCD cases were examined between 1994 and 2021. Sudden arrhythmic death syndrome (SADS), a morphologically normal heart, which can be underlaid by cardiac channelopathies, is most common (3821, 53%) followed by the cardiomyopathies (1558, 22%), then IHD (670, 9%), valve disease (225, 3%), congenital heart disease (213, 3%) and myocarditis/sarcoidosis (206, 3%). Hypertensive heart disease (185, 3%), aortic disease (129, 2%), vascular disease (97, 1%) and conduction disease (40, 1%) occur in smaller proportions. To our knowledge, this is the largest SCD cohort with autopsy findings ever reported from one country. SADS and cardiomyopathies predominate. This study highlights the importance of the autopsy in SCD, which is a significant public health concern in all age groups. Knowing the true incidence in our population will improve risk stratification and develop preventative strategies for family members. There is now a national pilot study integrating molecular autopsy and family screening into the assessment of SCD victims.

Sudden Cardiac Death Among Adolescents in the United Kingdom

BackgroundCauses and precipitating factors of sudden cardiac death (SCD) in adolescents are poorly understood. ObjectivesThe authors sought to investigate the etiologies of SCD and their association with physical activity in a large cohort of adolescents. MethodsBetween 1994 and June 2022, 7,675 cases of SCD were consecutively referred to our national cardiac pathology center; 756 (10%) were adolescents. All cases underwent detailed autopsy evaluation by expert cardiac pathologists. Clinical information was obtained from referring coroners. ResultsA structurally normal heart, indicative of sudden arrhythmic death syndrome was the most common autopsy finding (n = 474; 63%). Myocardial diseases were detected in 163 cases (22%), including arrhythmogenic cardiomyopathy (n = 36; 5%), hypertrophic cardiomyopathy (n = 31; 4%), idiopathic left ventricular hypertrophy (n = 31; 4%), and myocarditis (n = 30; 4%). Coronary artery anomalies were identified in 17 cases (2%). Decedents were competitive athletes in 128 cases (17%), and 159 decedents (21%) died during exercise. Arrhythmogenic cardiomyopathy was diagnosed in 8% of athletes compared with 4% of nonathletes (P = 0.05); coronary artery anomalies were significantly more common in athletes (9% vs 1%; P < 0.001), as well as commotio cordis (5% compared with 1% in nonathletes; P = 0.001). The 3 main comorbidities were asthma (n = 58; 8%), epilepsy (n = 44; 6%), and obesity (n = 40; 5%). ConclusionsSudden arrhythmic death syndrome and myocardial diseases are the most common conditions diagnosed at autopsy in adolescent victims of SCD. Among causes of SCD, arrhythmogenic cardiomyopathy, coronary artery anomalies, and commotio cordis are more common in young athletes than in similar age sedentary individuals.

Association of Cardiac Electrical Disorders With KCND3 Gene Mutation.

Globally, cardiac channelopathies leading to electrical disorders are responsible for a significant number of sudden cardiac deaths without structural heart disease. Many genes encoding different ion channels in the heart were identified and their impairment was found to be associated with life-threatening cardiac abnormalities. KCND3, one of the genes expressed both in the heart and brain, is reported to have an association with Brugada syndrome, early-onset atrial fibrillation, early repolarization syndrome, and sudden unexplained death syndrome. KCND3 genetic screening could be a promising tool for functional studies for an understanding of the pathogenesis and genetic determinants of the above-mentioned electrical disorders.