VIGOROUS EXERCISE AND SPORTS PARTICIPATION IN INDIVIDUALS WITH HYPERTROPHIC CARDIOMYOPATHY

Historically, individuals with HCM have been restricted from vigorous competitive sports due to concerns for risk of sudden death. More recently, prospective data are emerging that individuals with HCM who participate in vigorous sports do not have increased arrhythmic risk compared to the less active, and series of athletes with HCM continuing to compete, while small, have not shown high risk. Guidelines are evolving, and while differences exist, all now recommend an individualized approach and shared decision-making for athletes with HCM wishing to return to play.

The arrhythmic substrate of hypertrophic cardiomyopathy using ECG imaging

Introduction: Patients with hypertrophic cardiomyopathy (HCM) are at risk for lethal ventricular arrhythmia, but the electrophysiological substrate behind this is not well-understood. We used non-invasive electrocardiographic imaging to characterize patients with HCM, including cardiac arrest survivors. Methods: HCM patients surviving ventricular fibrillation or hemodynamically unstable ventricular tachycardia (n = 17) were compared to HCM patients without a personal history of potentially lethal arrhythmia (n = 20) and a pooled control group with structurally normal hearts. Subjects underwent exercise testing by non-invasive electrocardiographic imaging to estimate epicardial electrophysiology. Results: Visual inspection of reconstructed epicardial HCM maps revealed isolated patches of late activation time (AT), prolonged activation-recovery intervals (ARIs), as well as reversal of apico-basal trends in T-wave inversion and ARI compared to controls (p < 0.005 for all). AT and ARI were compared between groups. The pooled HCM group had longer mean AT (60.1 ms vs. 52.2 ms, p < 0.001), activation dispersion (55.2 ms vs. 48.6 ms, p = 0.026), and mean ARI (227 ms vs. 217 ms, p = 0.016) than structurally normal heart controls. HCM ventricular arrhythmia survivors could be differentiated from HCM patients without a personal history of life-threatening arrhythmia by longer mean AT (63.2 ms vs. 57.4 ms, p = 0.007), steeper activation gradients (0.45 ms/mm vs. 0.36 ms/mm, p = 0.011), and longer mean ARI (234.0 ms vs. 221.4 ms, p = 0.026). A logistic regression model including whole heart mean activation time and activation recovery interval could identify ventricular arrhythmia survivors from the HCM cohort, producing a C statistic of 0.76 (95% confidence interval 0.72-0.81), with an optimal sensitivity of 78.6% and a specificity of 79.8%. Discussion: The HCM epicardial electrotype is characterized by delayed, dispersed conduction and prolonged, dispersed activation-recovery intervals. Combination of electrophysiologic measures with logistic regression can improve differentiation over single variables. Future studies could test such models prospectively for risk stratification of sudden death due to HCM.

Predicting Out-of-Hospital Cardiac Arrest in the General Population Using Electronic Health Records

BACKGROUND

The majority of out-of-hospital cardiac arrests (OHCAs) occur among individuals in the general population, for whom there is no established strategy to identify risk. In this study, we assess the use of electronic health record (EHR) data to identify OHCA in the general population and define salient factors contributing to OHCA risk.

METHODS

The analytical cohort included 2366 individuals with OHCA and 23 660 age- and sex-matched controls receiving health care at the University of Washington. Comorbidities, electrocardiographic measures, vital signs, and medication prescription were abstracted from the EHR. The primary outcome was OHCA. Secondary outcomes included shockable and nonshockable OHCA. Model performance including area under the receiver operating characteristic curve and positive predictive value were assessed and adjusted for observed rate of OHCA across the health system.

RESULTS

There were significant differences in demographic characteristics, vital signs, electrocardiographic measures, comorbidities, and medication distribution between individuals with OHCA and controls. In external validation, discrimination in machine learning models (area under the receiver operating characteristic curve 0.80-0.85) was superior to a baseline model with conventional cardiovascular risk factors (area under the receiver operating characteristic curve 0.66). At a specificity threshold of 99%, correcting for baseline OHCA incidence across the health system, positive predictive value was 2.5% to 3.1% in machine learning models compared with 0.8% for the baseline model. Longer corrected QT interval, substance abuse disorder, fluid and electrolyte disorder, alcohol abuse, and higher heart rate were identified as salient predictors of OHCA risk across all machine learning models. Established cardiovascular risk factors retained predictive importance for shockable OHCA, but demographic characteristics (minority race, single marital status) and noncardiovascular comorbidities (substance abuse disorder) also contributed to risk prediction. For nonshockable OHCA, a range of salient predictors, including comorbidities, habits, vital signs, demographic characteristics, and electrocardiographic measures, were identified.

CONCLUSIONS

In a population-based case-control study, machine learning models incorporating readily available EHR data showed reasonable discrimination and risk enrichment for OHCA in the general population. Salient factors associated with OCHA risk were myriad across the cardiovascular and noncardiovascular spectrum. Public health and tailored strategies for OHCA prediction and prevention will require incorporation of this complexity.

Risk factors of sudden cardiac death in Egyptian patients younger than 40 years

BACKGROUND

Sudden cardiac death in young people is a major problem. The causes are well known; however, they may not be discovered before the episode of sudden death. A challenge for the future is identifying patients at risk before an episode of sudden cardiac death. Development of preventive and educational programs is required to identify sudden cardiac death/sudden cardiac arrest (SCD/SCA) risk factors, causes and characteristics. We aimed to study the characteristics of SCD/SCA in a cohort of young Egyptian population. Our retrospective cohort study included 246 patients of SCD/SCA who were collected from 5000 records of arrhythmia patients from January 2010 till January 2020. The records of the specialized arrhythmia clinic were reviewed to collect the families of SCD/SCA. All patients and/or their first-degree relatives were subjected to thorough history taking and clinical evaluation and investigations. Comparisons were done regarding age group and presence of positive family history of SCD.

RESULTS

Males constituted 56.9% of the study population. Mean age was 26.6 ± 12.73 years. Positive family history was present in 202 (82.1%) cases. Sixty-one percent of the cases had history of syncopal attacks. SCD/SCA during non-exertion or sleep occurred in 50.4% of cases. Hypertrophic cardiomyopathy was the most common cause of SCD/SCA (20.3%), followed by dilated cardiomyopathy (19.1%), long QT Syndrome (11.4%), complete heart block (8.5%), and Brugada syndrome (6.8%). In the older age group of 18-40 years, hypertrophic cardiomyopathy was responsible for SCD in 44 patients (25.3%) versus 6 patients (8.3%) in younger age group (p-value: 0.003). DCM was also dominant in older age group (42 patients; 24.1%) versus 5 patients (6.9%) in younger age group. Hypertrophic cardiomyopathy was more prevalent in positive family history group (46 patients; 22.8%) versus 4 patients (9.1%) in negative family history group (p-value: 0.041).

CONCLUSION

Family history of SCD was the most common risk factor of SCD. The most common cause of SCD in young Egyptian patients below 40 years was hypertrophic cardiomyopathy, followed by dilated cardiomyopathy. Both diseases were more common in the age group between 18 and 40 years. Hypertrophic cardiomyopathy was more common in patients with positive family history of SCD/SCA.

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

AIMS

Sudden cardiac death (SCD) is defined as natural unexpected death in witnessed cases occurring < 1 h and in unwitnessed cases as last seen alive < 24 h. 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.

METHODS AND RESULTS

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.

DISCUSSION

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.

Dofetilide use is not associated with increased mortality in patients with left ventricular hypertrophy and atrial fibrillation

BACKGROUND

Left ventricular hypertrophy (LVH) is common in patients with atrial fibrillation (AF), however, many antiarrhythmic drugs (AADs) are contraindicated. US guidelines recommend avoiding pure class III antiarrhythmics such as dofetilide in patients with significant LVH due to concern for an increased risk of death, however, clinical data is lacking. We sought to determine if dofetilide use was associated with increased mortality in patients with LVH.

METHODS

Patients ≥18 years of age with AF and LVH ≥ 1.4 cm were included. A group of patients treated with dofetilide and a control group of patients without a history of AAD use were propensity matched. The primary outcome was all-cause mortality at 3 years and secondary outcomes were total number of all-cause hospitalizations and hospitalizations related to AF.

RESULTS

There were 359 patients in each of the groups. Baseline variables were well-matched. The primary outcome of all-cause mortality occurred in 7% of patients in the dofetilide group and 12% of patients in the control group (hazard ratio: 0.90, 95% confidence interval: 0.53-1.53). Total all-cause hospitalizations were higher in the control group but hospitalizations for AF were no different.

CONCLUSIONS

In a propensity-matched cohort of 718 patients with AF and LVH, dofetilide was not associated with increased mortality at 3 years. Our study adds to prior data demonstrating the safety of dofetilide in this population despite guideline recommendations against its use. Given the limited options for AF management in LVH patients, dofetilide may be reasonable for symptomatic AF management.

A systematic review of global autopsy rates in all-cause mortality and young sudden death

Autopsy is the gold standard method for determining cause of death. Young sudden death (SD) is a prototype condition in which autopsy is universally recommended. The aim of this review was to quantify real-world global rates of autopsy in either all-cause death or young SD. A systematic review was conducted. Rates of autopsy in all-cause death and in young SD were determined in each country using scientific and commercial search engines. In total, 59 of 195 countries (30.3%) reported autopsy rates in all-cause death, with rates varying from 0.01%-83.9%. Almost all of these figures derived from academic publications rather than governmental statistics. Only 16 of 195 countries (8.2%) reported autopsy rates in the context of young SD, with reported rates ranging from 5%-100%. The definition of "young" was heterogeneous. No governmental statistics reported autopsy rates in young SD. Risks of bias included inability to verify reported figures, heterogeneity in reporting of clinical vs medicolegal autopsies, and the small number of studies identified overall, resulting in the consistent exclusion of low- and middle-income countries. In conclusion, most countries globally do not report autopsy rates in either all-cause death (69.7%) or in SD (92.8%). Without transparent reporting of autopsy rates, global burdens of disease and rates of sudden cardiac death cannot be reliably calculated.

Prevalence and characteristics of family history of sudden unexplained death and predictors of negative attitude of family members toward medical autopsy and family screening in Saudi Arabia: A cross-sectional study

INTRODUCTION

Little is known about sudden unexplained death (SUD) in Saudi Arabia. Moreover, family screening and medical autopsy are not routinely performed due to perceived religious and cultural resistance. However, this has never been systematically examined. We sought to describe the prevalence and characteristics of family history of SUD and the attitude of family members toward medical autopsy and family screening.

METHODS

This was a cross-sectional study utilizing an online survey distributed though social media platforms from August 15 to September 15, 2021. Participants' characteristics, details about SUD cases, and the attitude toward medical autopsy and family screening were collected. Multivariable logistic regression was used to identify independent predictors of negative attitude toward medical autopsy.

RESULTS

A total of 11374 were included in the final analysis after excluding children. The prevalence of FHx of at least one first degree relative (FDR) with SUD was found to be 9.4% [95% CI (8.9% - 10%)]. Among participants with any FHx of SUD, 1346/3489 (38.6%) had ≥ 2 family members affected. Only 183 participants with a FHx of SUD visited a physician for the purpose of family screening (183/3489, 5.3%). The total number of SUD cases reported was 5474. Of those, 22% were 35-year-old or younger. Only 22% of participants (2458/11374) had a negative attitude towards medical autopsy, and the most common reason was the perceived lack of benefit. Older age (> 35 years), family history of SUD, female gender, and lack of knowledge about the yield of medical autopsy were associated with negative attitude in the adjusted analysis.

CONCLUSION

SUD occurred at young age and affected multiple family members in a significant proportion of families. Despite that, family screening was seldom performed. There is an urgent need to improve the care of SUD by incorporating medical autopsy and developing clinical pathways to screen family members.

Medical Autopsy for Sudden Unexplained Death in Saudi Arabia: A Call to Action

Sudden unexplained death (SUD) is a sudden, unexpected, and unexplained death in an individual older than 1 year. It is one of the most devastating and tragic events to families and the community at large, particularly when it happens at a young age. Finding the cause of SUD is extremely important in order to prevent its recurrence in the family, and to help understand the epidemiology of SUD in the community. It has been well-established that the most effective way of finding the cause of SUD is by performing a medical autopsy. In many countries, medical autopsy is mandated in SUD cases. In others, however, medical autopsy is rarely performed for the purpose of identifying the cause of SUD, which is the case in Saudi Arabia. In this review, we discussed the importance of finding the cause of death in SUD cases, the role of different types of medical autopsies, and the state of medical autopsy in Saudi Arabia. Moreover, we proposed a clinical pathway to incorporate medical autopsy in the care of SUD cases, and to connect family members to the health care system in order to perform cascade screening.

Better outcomes from exercise-related out-of-hospital cardiac arrest in males and in the young: findings from the Swedish Registry of Cardiopulmonary Resuscitation

BACKGROUND

Survival from out-of-hospital cardiac arrest (OHCA) is higher if the arrest is witnessed and occurs during exercise, however, there is contradicting data on prognosis with regards to sex and age. The purpose of this study was to compare the outcomes and circumstances of exercise-related OHCA in different age groups and between sexes in a large unselected population.

METHODS

Data from exercise-related OHCAs reported to the Swedish Registry of Cardiopulmonary Resuscitation from 2011 to 2014 and from 2016 to 2018 were analysed. All cases of exercise-related OHCA in which emergency medical services attempted resuscitation were included. The primary outcome was survival to 30 days.

RESULTS

In total, 635 cases of exercise-related OHCA outside of the home were identified. The overall 30-day survival rate was 44.5% with highest survival rate in the age group 0-35 years, compared with 36-65 years and >65 years (59.6% vs 46.0% and 40.4%, p=0.01). A subgroup analysis of 0-25 years showed a survival rate of 68.8%. Exercise-related OHCA in females (9.1% of total) were witnessed to a lower extent (66.7% vs 79.6%, p=0.03) and median time to cardiopulmonary resuscitation (CPR) was longer (2.0 vs 1.0 min, p=0.001) than in males. Females also had lower rates of ventricular fibrillation (43.4% vs 64.7%, p=0.003) and a lower 30-day survival rate (29.3% vs 46.0%, p=0.02).

CONCLUSION

In exercise-related OHCA, younger victims have a higher survival rate. Exercise-related OHCA in females was rare, however, survival rates were lower compared with males and partly explained by a lower proportion of witnessed events, longer time to CPR and lower frequency of a shockable rhythm.

Genetics and genomics of arrhythmic risk: current and future strategies to prevent sudden cardiac death

A genetic risk of sudden cardiac arrest and sudden death due to an arrhythmic cause, known as sudden cardiac death (SCD), has become apparent from epidemiological studies in the general population and in patients with ischaemic heart disease. However, genetic susceptibility to sudden death is greatest in young people and is associated with uncommon, monogenic forms of heart disease. Despite comprehensive pathology and genetic evaluations, SCD remains unexplained in a proportion of young people and is termed sudden arrhythmic death syndrome, which poses challenges to the identification of relatives from affected families who might be at risk of SCD. In this Review, we assess the current understanding of the epidemiology and causes of SCD and evaluate both the monogenic and the polygenic contributions to the risk of SCD in the young and SCD associated with drug therapy. Finally, we analyse the potential clinical role of genomic testing in the prevention of SCD in the general population.

Sudden cardiac death in persons aged 50 years or younger: diagnostic yield of a regional molecular autopsy program using massive sequencing

INTRODUCTION AND OBJECTIVES

Sudden cardiac death (SCD) in young people often has a genetic cause. Consequently, the results of "molecular autopsy" may have important implications for their relatives. Our objective was to evaluate the diagnostic yield of a molecular autopsy program using next-generation sequencing.

METHODS

We performed a prospective study of a cohort of consecutive patients who died from nonviolent SCD, aged ≤ 50 years, and who underwent molecular autopsy using large panels of next-generation sequencing, with subsequent clinical and genetic family screening. We analyzed demographic, clinical, toxicological, and genetic data.

RESULTS

We studied 123 consecutive cases of SCD in persons aged ≤ 50 years. The incidence of SCD was 5.8 cases/100 000 individuals/y, mean age was 36.15±12.7 years, and 95 were men (77%). The cause was cardiac in 53%, unexplained SCD in 24%, toxic in 10.6%, and infant SCD in 4%. Among cardiac causes, ischemic heart disease accounted for 38% of deaths, arrhythmogenic cardiomyopathy for 7%, hypertrophic cardiomyopathy for 5%, and idiopathic left ventricular hypertrophy for 11%. Genetic analysis was performed in 62 cases (50.4%). Genetic variants were found in 42 cases (67.7%), with a mean of 3.4±4 genetic variants/patient, and the variant found was considered to be pathogenic or probably pathogenic in 30.6%. In unexplained SCD, 70% showed some genetic variant. Family screening diagnosed 21 carriers or affected individuals, 5 of whom were at risk, indicating an implantable cardiac defibrillator.

CONCLUSIONS

Protocol-based and exhaustive study of SCD from cardiac causes in persons aged ≤ 50 years is feasible and necessary. In a high percentage of cases, the cause is genetic, indicating the existence of relatives at risk who could benefit from early diagnosis and treatment to avoid complications.

Global approaches to cardiogenetic evaluation after sudden cardiac death in the young: A survey among health care professionals

BACKGROUND

Thorough investigation of sudden cardiac death (SCD) in those aged 1-40 years commonly reveals a heritable cause, yet access to postmortem genetic testing is variable.

OBJECTIVE

The purpose of this study was to explore practices of postmortem genetic testing and attitudes of health care professionals worldwide.

METHODS

A survey was administered among health care professionals recruited through professional associations, social media, and networks of researchers. Topics included practices around postmortem genetic testing, level of confidence in health care professionals' ability, and attitudes toward postmortem genetic testing practices.

RESULTS

There were 112 respondents, with 93% from North America, Europe, and Australia/New Zealand, and 7% from South America, Asia and Africa. Only 30% reported autopsy as mandatory, and overall practices were largely case by case and not standardized. North American respondents (87%) more often perceived practices as ineffective compared to those from Europe (58%) and Australia/New Zealand (48%; P = .002). Where a heritable cause is suspected, 69% considered postmortem genetic testing and 61% offered genetic counseling to surviving family members. Financial resources varied widely. Half of participants believed practices in their countries perpetuated health inequalities.

CONCLUSION

Postmortem genetic testing is not consistently available in the investigation of young SCD despite being a recommendation in international guidelines. Access to postmortem genetic testing, which is critical in ascertaining a cause of death in many cases, must be guided by well-resourced, multidisciplinary teams.

Sudden Death and Coronary Artery Anomalies

Congenital coronary artery anomalies (CAA) include a wide spectrum of malformations present at birth with various clinical manifestations and degrees of severity. Patients may be asymptomatic, and CAA may be an incidental finding during cardiac imaging or at autopsy. However, in other cases, ischemia-related signs and symptoms, leading to an increased risk of sudden cardiac death (SCD), often as first presentation may occur. In this chapter, we discuss the normal anatomy of the coronary arteries (CA) and the pathology of CAA at risk of SCD, including our experience with victims of SCD among the young population (age <40 years) and among athletes.

Diagnostic yield and financial implications of a nationwide electrocardiographic screening programme to detect cardiac disease in the young

Aims

There is limited information on the role of screening with electrocardiography (ECG) for identifying cardiovascular diseases associated with sudden cardiac death (SCD) in a non-select group of adolescents and young adults in the general population.

Methods and results

Between 2012 and 2014, 26 900 young individuals (aged 14–35 years) were prospectively evaluated with a health questionnaire and ECG. Individuals with abnormal results underwent secondary investigations, the costs of which were being based on the UK National Health Service tariffs. Six hundred and seventy-five (2.5%) individuals required further investigation for an abnormal health questionnaire, 2175 (8.1%) for an abnormal ECG, and 114 (0.5%) for both. Diseases associated with young SCD were identified in 88 (0.3%) individuals of which 15 (17%) were detected with the health questionnaire, 72 (81%) with ECG and 2 (2%) with both. Forty-nine (56%) of these individuals received medical intervention beyond lifestyle modification advice in the follow-up period of 24 months. The overall cost of the evaluation process was €97 per person screened, €17 834 per cardiovascular disease detected, and €29 588 per cardiovascular disease associated with SCD detected. Inclusion of ECG was associated with a 36% cost reduction per diagnosis of diseases associated with SCD compared with the health questionnaire alone.

Conclusion

The inclusion of an ECG to a health questionnaire is associated with a five-fold increase in the ability to detect disease associated with SCD in young individuals and is more cost effective for detecting serious disease compared with screening with a health questionnaire alone.

Sudden Cardiac Death in Athletes in Italy during 2019: Internet-Based Epidemiological Research

Background and objectives: An Italian nationwide pre-participation screening approach for prevention of sudden cardiac death in athletes (SCD-A) in competitive sportspeople showed promising results but did not achieve international consensus, due to cost-effectiveness and the shortfall of a monitoring plan. From this perspective, we tried to provide an epidemiological update of SCD-A in Italy through a year-long internet-based search. Materials and Methods: One year-long Google search was performed using mandatory and non-mandatory keywords. Data were collected according to prevalent SCD-A definition and matched with sport-related figures from Italian National Institute of Statistics (ISTAT) and Italian National Olympic Committee (CONI). Results: Ninety-eight cases of SCD-A in 2019 were identified (48.0% competitive, 52.0% non-competitive athletes). Male/female ratio was 13:1. The most common sports were soccer (33.7%), athletics (15.3%) and fitness (13.3%). A conclusive diagnosis was achieved only in 37 cases (33 of cardiac origin), with the leading diagnosis being coronary artery disease in 27 and a notably higher occurrence among master athletes. Combining these findings with ISTAT and CONI data, the SCD-A incidence rate in the whole Italian sport population was found to be 0.47/100,000 persons per year (1.00/100,000 in the competitive and 0.32/100,000 in the non-competitive population). The relative risk of SCD-A is 3.1 (CI 2.1–4.7; p < 0.0001) for competitive compared to non-competitive athletes; 9.9 for male (CI 4.6–21.4; p < 0.0001) with respect to female. Conclusions: We provided an updated incidence rate of SCD-A in both competitive and non-competitive sport in Italy. A higher risk of SCD-A among competitive and male athletes was confirmed, thus corroborating the value of Italian pre-participation screening in this population.

Sudden death in the young adult: a Tunisian autopsy-based series

Background

We aim to study the profile, and pathological characteristics of sudden death in young in purpose of recommendations for prevention.

Methods

We performed a retrospective cohort study using autopsy data from the Department of Forensic Medicine of Monastir (Tunisia). A review of all autopsies performed for 28 years was done (August 1990 to December 2018). In each case, clinical information, and circumstances of death were obtained. A complete forensic autopsy and histological, and toxicological investigations were performed. We have included all sudden death in persons aged between 18 and 35 years.

Results

We collected 137 cases of sudden death during the studied period. The mean age of the studied population was 26.47 years. Almost 72% deaths were classified as cardiac death, and was due to ischemic heart disease in 32.32%. Sudden death was attributed to a pleuropulmonary cause in 7.4%, an abdominal cause in 6%, and from a neurological origin in 4.5%. The cause of sudden death in this group was not established by 9.5%.

Conclusion

In this series, sudden death in young adults occurs mainly in a smoking male, aged between 18 and 24 years old, occurring at rest, in the morning, and early in the week. It is more common, especially in summer. Sudden death is most often the first manifestation of pathologies, especially unsuspected heart diseases. The predominance of cardiovascular causes is the common denominator of almost all studies reported in the literature. Our findings suggest that prevention of sudden death among young adults under the age of 35 years should also focus on evaluation for causes not associated with structural heart disease.

Incidence and etiology of sudden cardiac arrest in Koreans: A cohort from the national health insurance service database

The incidence of sudden cardiac arrest (SCA) in Asians is lower than that seen in Western populations, but there are few available data on the incidence and associated cardiac etiology of SCA in Asians. From 2002 to 2013, patients with SCA were analyzed using a cohort from the South Korean National Health Insurance Service (NHIS) coded database. Sudden unexplained death syndrome (SUDS) was defined as cryptogenic arrest, excluding that of non-cardiac origin, coronary artery disease (CAD), cardiomyopathy (CM), and valvular heart disease. During the 12-year study period, 5,973 patients (0.53%) from the total cohort of 1,125,691 had a cardiac arrest code. The overall incidence of arrest was 48.7 per 100,000 person-years (95% CI 16.6-18.0). The incidence of primary SCA excluding those of non-cardiac origin was 16.1 per 100,000 person-years (95% CI 15.4-16.8). It was higher in males than in females (18.1 vs. 14.1 per 100,000 person-years). CAD was the most common cause of SCA (59.4%), and followed by CM (13.9%). SUDS accounted for 14.7% of SCA events. The risk of SCA had increased gradually from over 25 years old. Heart failure, atrial fibrillation and hypertension are major factors associated with SCA incidence. Our findings outline epidemiologic data for SCA and the proportion of associated cardiac etiology leads SCA in a large population.

Sudden Cardiac Death in the Young: Incidence, Trends, and Risk Factors in a Nationwide Study

BACKGROUND

Sudden cardiac death (SCD) in the young is devastating. Contemporary incidence remains unclear with few recent nationwide studies and limited data addressing risk factors for causes. We aimed to determine incidence, trends, causes, and risk factors for SCD in the young.

METHODS AND RESULTS

The National Coronial Information System registry was reviewed for SCD in people aged 1 to 35 years from 2000 to 2016 in Australia. Subjects were identified by the International Classification of Diseases, Tenth Revision code relating to circulatory system diseases (I00-I99) from coronial reports. Baseline demographics, circumstances, and cause of SCD were obtained from coronial and police reports, alongside autopsy and toxicology analyses where available. During the study period, 2006 cases were identified (median age, 28±7 years; men, 75%; mean body mass index, 29±8 kg/m²). Annual incidence ranged from 0.91 to 1.48 per 100 000 age-specific person-years, which was the lowest in 2013 to 2015 compared with previous 3-year intervals on Poisson regression model (P=0.001). SCD incidence was higher in nonmetropolitan versus metropolitan areas (0.99 versus 0.53 per 100 000 person-years; P<0.001). The most common cause of SCD was coronary artery disease (40%), followed by sudden arrhythmic death syndrome (14%). Incidence of coronary artery disease-related SCD decreased from 2001-2003 to 2013-2015 (P<0.001). Proportion of SCD related to sudden arrhythmic death syndrome increased during the study period (P=0.02) although overall incidence was stable (P=0.22). Residential remoteness was associated with coronary artery disease-related SCD (odds ratio, 1.44 [95% CI, 1.24-1.67]; P<0.001). For every 1-unit increase, body mass index was associated with increased likelihood of SCD from cardiomegaly (odds ratio, 1.08 [95% CI, 1.05-1.11]; P<0.001) and dilated cardiomyopathy (odds ratio, 1.04 [95% CI, 1.01-1.06]; P=0.005).

CONCLUSIONS

Incidence of SCD in the young and specifically coronary artery disease-related SCD has declined in recent years. Proportion of SCD related to sudden arrhythmic death syndrome increased over the study period. Geographic remoteness and obesity are risk factors for specific causes of SCD in the young.

Incidence of sudden cardiac death in the young: a systematic review

OBJECTIVE

To summarise studies describing incidence of sudden cardiac death in a general population of young individuals to inform screening policy.

DESIGN

Systematic review.

DATA SOURCES

Database searches of MEDLINE, EMBASE and the Cochrane library (all inception to current) on 29 April 2019 (updated 16 November 2019), and forward/backward citation tracking of eligible studies.

STUDY ELIGIBILITY CRITERIA

All studies that reported incidence of sudden cardiac death in young individuals (12-39 years) in a general population, with no restriction on language or date. Planned subgroups were incidence by age, sex, race and athletic status (including military personnel).

DATA EXTRACTION

Two reviewers independently assessed study eligibility, extracted study data and assessed risk of bias using the Joanna Briggs Institute critical appraisal checklist for prevalence studies.

ANALYSIS

Reported incidence of sudden cardiac death in the young per 100 000 person-years.

RESULTS

38 studies that reported incidence across five continents. We identified substantial heterogeneity in population, sudden cardiac death definition, and case ascertainment methods, precluding meta-analysis. Median reported follow-up years was 6.97 million (IQR 2.34 million-23.70 million) and number of sudden cardiac death cases was 64 (IQR 40-251). In the general population, the median of reported incidence was 1.7 sudden cardiac death per 100 000 person-years (IQR 1.3-2.6, range 0.75-11.9). Most studies (n=14, 54%) reported an incidence between one and two cases per 100 000 person-years. Incidence was higher in males and older individuals.

CONCLUSIONS

This systematic review identified variability in the reported incidence of sudden cardiac death in the young across studies. Most studies reported an incidence between one and two cases per 100 000 person-years.

PROSPERO REGISTRATION NUMBER

CRD42019120563.

Are Irish Gaelic Athletic Association clubs prepared to use an AED following a sudden cardiac arrest? A cross-sectional survey

Objectives: To identify the availability and accessibility of AEDs in Irish GAA clubs and the knowledge, willingness, and confidence of club members to use AEDs in a medical emergency. Methods: A self-report survey was completed anonymously by GAA club members (n = 267). The survey captured demographic information, previous formal AED training, awareness of AED access in their local GAA club and knowledge, confidence, and willingness to use an AED in a medical emergency and awareness of a written club emergency action plan (EAP). Descriptive statistics were used to examine survey responses and independent samples t-tests to compare differences in outcome scores between those who have or have not completed formal AED training and those that have or have not studied toward or worked in a health-care provision role. Results: Three in every five GAA club members reported that their club owned an AED and almost half of all respondents had access to a club AED in the event of a medical emergency in their club. Formal training was noted by 53.2% of respondents; this group demonstrated significantly better knowledge, confidence, and willingness (p < 0.0001) than those without. Few (7%) respondents knew where the club EAP was or how to access it. Conclusion: To ensure the chain of survival works effectively it is essential that an AED is available, is accessible, and that club members know its location, know when to use it, and are willing and confident to use it. GAA clubs should design an individual emergency action plan and disseminate it widely among club members. Formal AED training should be encouraged among club members and at least one trained member should be present during all club activities.

SVAD: A genetic database curates non-ischemic sudden cardiac death-associated variants

Sudden cardiac death (SCD) is an important cause of mortality worldwide. It accounts for approximately half of all deaths from cardiovascular disease. While coronary artery disease and acute myocardial infarction account for the majority of SCD in the elderly population, inherited cardiac diseases (inherited CDs) comprise a substantial proportion of younger SCD victims with a significant genetic component. Currently, the use of next-generation sequencing enables the rapid analysis to investigate relationships between genetic variants and inherited CDs causing SCD. Genetic contribution to risk has been considered an alternate predictor of SCD. In the past years, large numbers of SCD susceptibility variants were reported, but these results are scattered in numerous publications. Here, we present the SCD-associated Variants Annotation Database (SVAD) to facilitate the interpretation of variants and to meet the needs of data integration. SVAD contains data from a broad screening of scientific literature. It was constructed to provide a comprehensive collection of genetic variants along with integrated information regarding their effects. At present, SVAD has accumulated 2,292 entries within 1,239 variants by manually surveying pertinent literature, and approximately one-third of the collected variants are pathogenic/likely-pathogenic following the ACMG guidelines. To the best of our knowledge, SVAD is the most comprehensive database that can provide integrated information on the associated variants in various types of inherited CDs. SVAD represents a valuable source of variant information based on scientific literature and benefits clinicians and researchers, and it is now available on http://svad.mbc.nctu.edu.tw/.

[Death due to myocardial infarction in young patients: A study of 312 cases of sudden death]

Sudden cardiac death in young is seen as a dramatic phenomenon requiring knowledge of its impact. We aim to study the epidemiological characteristics of sudden cardiac ischemic death in young, and to discuss his involvement in the occurrence of death. We performed a retrospective cohort study using autopsy data from the department of forensic medicine of the University Hospital of Fattouma Bourguiba, Monastir-Tunisia. A review of all autopsies performed during 23 years was done. In each case, clinical information and circumstances of death were obtained. We have included all sudden death in persons aged between 1 year and 35 years for the male and from one year to 45 years for female. We collected 312 cases of sudden death during the studied period. The collected data were processed using SPSS 20. The significance level was set at 0.05. Thirty-two cases of cardiac ischemic sudden death have been collected. Myocardial infarction was the second cause of sudden death in young patients. There was a male predominance. The most affected subjects were aged between 25-45 years. The death occurred more frequently at rest. Coronary artery disease has been discovered in twenty-four cases (75%). The myocardial infarction occurred on healthy coronary arteries in eight cases. An anomalous course of coronary arteries, in particular myocardial bridging, was found in eight cases (25%). Toxicological screening was negative in all cases. Identifying epidemiological characteristics of sudden cardiac ischemic death in this population is important for guiding approaches to prevention that must be based on dietary hygienic measures and the control of cardiovascular risk factors.

Epidemiology of Sudden Death in a Population-Based Study of Infants and Children

Objective

To describe epidemiologic data from the Sudden Death in the Young (SDY) Case Registry. Understanding the scope of SDY may optimize prevention efforts.

Study design

We analyzed sudden, unexpected deaths of infants (<365 days) and children (1–17 years) from a population-based registry of 8 states/jurisdictions in 2015 and 9 in 2016. Natural deaths and injury deaths from drowning, motor vehicle accident drivers, and infant suffocation were included; other injury deaths, homicide, suicide, intentional overdose, and terminal illness were excluded. Cases were categorized using a standardized algorithm. Descriptive statistics were used to characterize deaths, and mortality rates were calculated.

Results

Of 1319 cases identified, 92% had an autopsy. We removed incomplete cases, leaving 1132 analyzable deaths (889 infants, 243 children). The SDY rate for infants was 120/100 000 live births and for children was 1.9/100 000 children. Explained Cardiac rates were greater for infants (2.7/100 000 live births) than children (0.3/100 000 children). The pediatric Sudden Unexpected Death in Epilepsy (SUDEP) mortality rate was 0.2/100 000 live births and children. Blacks comprised 42% of infant and 43% of child deaths but only 23% of the population. In all ages, myocarditis/endocarditis was the most common Explained Cardiac cause; respiratory illness was the most common Explained Other cause. SDY occurred during activity in 13% of childhood cases.

Conclusions

Prevention strategies include optimizing identification and treatment of respiratory and cardiac diseases.

Electrocardiographic changes and long-term prognosis of children diagnosed with hypertrophic cardiomyopathy by the school screening program for heart disease in Japan

BACKGROUND

In Japan, the school screening program for heart disease (SS) has been performed since 1973. However, little has been reported on the electrocardiogram (ECG) changes and long-term prognosis in patients with hypertrophic cardiomyopathy (HCM) detected by the SS.

METHODS

All 44 consecutive pediatric HCM patients (10.1 ± 3.0 years old), who had been originally consulted by the SS before the diagnosis of HCM from April 1981 to April 2017, were reviewed retrospectively.

RESULTS

At the SS, all patients showed mild or no symptoms. All patients showed ECG abnormalities, and 75 % had a high proposed ECG risk score (≧6). However, 30 % of them had no echocardiogram finding of myocardial hypertrophy. During the follow-up period (14.8 ± 10.0 years), life-threatening events (LTE) occurred in 11 (25 %) patients, and the first LTE occurred during exercise in 8 (18 %). The estimated LTE and heart failure death-free survival rate at 10 years was 64.9 %. The LTE-free survival rate was lower in patients without than in those with myocardial hypertrophy at the SS.

CONCLUSIONS

The SS was useful in detecting patients with HCM with mild or no symptoms at the early stage. However, our study indicated that early detection of HCM is not associated with improvement in the prognosis of the patients. Further studies are needed.

Hypertrophic Cardiomyopathy–Related Sudden Cardiac Death in Young People in Ontario

Background:

Hypertrophic cardiomyopathy (HCM) is considered a leading cause of sudden cardiac death (SCD) in younger people. The incidence of HCM-related SCD and its relationship to exercise have not been well studied in large comprehensive studies outside of tertiary care settings. This study sought to estimate the incidence of HCM-related SCD and its association with exercise in a large unselected population.

Methods:

Using the Office of the Chief Coroner of Ontario database encompassing all deaths attended by the coroner, we identified all HCM-related SCDs in individuals 10 to 45 years of age between 2005 and 2016 (70 million person-years). Confirmation of HCM was based on typical macroscopic and microscopic features (definite HCM-related SCD). Sudden deaths with a prior clinical diagnosis of HCM but no autopsy were considered probable HCM-related SCDs. Cases with typical features but no myofiber disarray were considered possible HCM. The completeness of data was verified in a subset of patients in the Toronto area with the use of a registry of all emergency medical services–attended cardiac arrests, with an autopsy rate of 94%. To estimate the number of HCM-related aborted cardiac arrests and lives potentially saved by implantable cardioverter-defibrillators, all de novo implantations for secondary prevention and all implantations and appropriate shocks for primary prevention in patients with HCM 10 to 45 years of age, respectively, were identified with the use of a registry containing data on implantable cardioverter-defibrillator implantations from all implanting sites throughout Ontario.

Results:

Forty-four, 3, and 6 cases of definite, probable, and possible HCM-related SCDs, respectively, were identified, corresponding to estimated annual incidence rates of 0.31 per 1000 HCM person-years (95% CI, 0.24–0.44) for definite HCM-related SCD, 0.33 per 1000 HCM person-years (95% CI, 0.34–0.62) for definite or probable HCM-related SCD, and 0.39 per 1000 HCM person-years (95% CI, 0.28–0.49) for definite, probable, or possible HCM-related SCD (estimated 140 740 HCM person-years of observation). The estimated annual incidence rate for HCM-related SCD plus aborted cardiac arrest and HCM-related life-threatening arrhythmia (SCD, aborted cardiac arrest, and appropriate implantable cardioverter-defibrillator shocks) was 0.84 per 1000 HCM person-years (95% CI, 0.70–1.0). The majority (70%) of SCDs occurred in previously undiagnosed individuals. Most SCDs occurred during rest (64.8%) or light activity (18.5%).

Conclusions:

The incidence of HCM-related SCD in the general population 10 to 45 years of age is substantially lower than previously reported, with most cases occurring in previously undiagnosed individuals. SCDs are infrequently related to exercise.

Cardiac Arrhythmias in Africa: Epidemiology, Management Challenges, and Perspectives

Africa is experiencing an increasing burden of cardiac arrhythmias. Unfortunately, the expanding need for appropriate care remains largely unmet because of inadequate funding, shortage of essential medical expertise, and the high cost of diagnostic equipment and treatment modalities. Thus, patients receive suboptimal care. A total of 5 of 34 countries (15%) in Sub-Saharan Africa (SSA) lack a single trained cardiologist to provide basic cardiac care. One-third of the SSA countries do not have a single pacemaker center, and more than one-half do not have a coronary catheterization laboratory. Only South Africa and several North African countries provide complete services for cardiac arrhythmias, leaving more than hundreds of millions of people in SSA without access to arrhythmia care considered standard in other parts of the world. Key strategies to improve arrhythmia care in Africa include greater government health care funding, increased emphasis on personnel training through fellowship programs, and greater focus on preventive care.

Mitral Valve Prolapse, Ventricular Arrhythmias, and Sudden Death

Despite a 2% to 3% prevalence of echocardiographically defined mitral valve prolapse (MVP) in the general population, the actual burden, risk stratification, and treatment of the so-called arrhythmic MVP are unknown. The clinical profile is characterized by a patient, usually female, with mostly bileaflet myxomatous disease, mid-systolic click, repolarization abnormalities in the inferior leads, and complex ventricular arrhythmias with polymorphic/right bundle branch block morphology, without significant regurgitation. Among the various pathophysiologic mechanisms of electrical instability, left ventricular fibrosis in the papillary muscles and inferobasal wall, mitral annulus disjunction, and systolic curling have been recently described by pathological and cardiac magnetic resonance studies in sudden death victims and patients with arrhythmic MVP. In addition, premature ventricular beats arising from the Purkinje tissue as ventricular fibrillation triggers have been documented by electrophysiologic studies in MVP patients with aborted sudden death.

The genesis of malignant ventricular arrhythmias in MVP probably recognizes the combination of the substrate (regional myocardial hypertrophy and fibrosis, Purkinje fibers) and the trigger (mechanical stretch) eliciting premature ventricular beats because of a primary morphofunctional abnormality of the mitral valve annulus.

The main clinical challenge is how to identify patients with arrhythmic MVP (which imaging technique and in which patient) and how to treat them to prevent sudden death. Thus, there is a necessity for prospective multicenter studies focusing on the prognostic role of cardiac magnetic resonance and electrophysiologic studies and on the therapeutic efficacy of targeted catheter ablation and mitral valve surgery in reducing the risk of life-threatening arrhythmias, as well as the role of implantable cardioverter defibrillators for primary prevention.

Evaluation After Sudden Death in the Young

Sudden cardiac death is defined as a death occurring usually within an hour of onset of symptoms, arising from an underlying cardiac disease. Sudden cardiac death is a complication of a number of cardiovascular diseases and is often unexpected. In individuals aged <35 years, unexplained sudden cardiac death is the most common presentation. A significant proportion of sudden cardiac death in the young (≤35 years) events may be precipitated by underlying inherited cardiac conditions, including both heritable cardiomyopathies and inherited arrhythmia syndromes (also known as cardiac channelopathies). Tragically, sudden death may be the first manifestation of the disease in a family and, therefore, clinical and genetic evaluation of surviving family members forms a key role in diagnosing the underlying inherited cardiac condition in the family. This is particularly relevant when considering that most inherited cardiac conditions are inherited in an autosomal dominant manner meaning that surviving family members have a 50% chance of inheriting the same disease substrate. This review will outline the underlying causes of sudden cardiac death in the young and outline our universal approach to familial evaluation following a young person’s sudden death.

The Taiwan Heart Registries: Its Influence on Cardiovascular Patient Care

Taiwanese heart registries for the main cardiovascular diseases have been conducted in the past 10 years, with the goal of examining the quality of cardiovascular patient care, which cannot be guaranteed by the universal Taiwan National Health Insurance. The results show suboptimal adherence to guideline recommendations. Door-to-balloon time and dual antiplatelet therapy use in acute coronary syndrome, standard medications for management of heart failure, low-density lipoprotein cholesterol levels in dyslipidemia, anticoagulant agent use in atrial fibrillation, and the understanding of sudden arrhythmia death syndrome were all found to be inadequate. However, all were improved, either by changing National Health Insurance policy or through continuous education for physicians and patients. Thus, specific cardiovascular disease registries could help examine the status of real-world practice, find inadequacies in guideline implementation and understanding of rare diseases, facilitate lobbying to policy makers and education for physicians and patients, and influence and improve cardiovascular patient care.

Echocardiography in Athletes in Primary Prevention of Sudden Death

Echocardiography is a noninvasive imaging technique useful to provide clinical data regarding physiological adaptations of athlete's heart. Echocardiographic characteristics may be helpful for the clinicians to identify structural cardiac disease, responsible of sudden death during sport activities. The application of echocardiography in preparticipation screening might be essential: it shows high sensitivity and specificity for identification of structural cardiac disease and it is the first-line imagining technique for primary prevention of SCD in athletes. Moreover, new echocardiographic techniques distinguish extreme sport cardiac remodeling from beginning state of cardiomyopathy, as hypertrophic or dilated cardiomyopathy and arrhythmogenic right ventricle dysplasia. The aim of this paper is to review the scientific literature and the clinical knowledge about athlete's heart and main structural heart disease and to describe the rule of echocardiography in primary prevention of SCD in athletes.

Can epinephrine therapy be detrimental to patients with hypertrophic cardiomyopathy with hypotension or cardiac arrest? A systematic review

Approximately 10% of sudden cardiac deaths among patients under 35 years of age is owing to hypertrophic cardiomyopathy (HCM)-related cardiac arrest (CA). CA is often associated with pre-arrest or peri-arrest hypotension and is treated by a set of interventions, including the administration of epinephrine. It is debated whether epinephrine increases or decreases survival to discharge following CA. HCM is associated with septal hypertrophy with a dynamic left ventricular outflow tract obstruction and impaired peripheral vasoconstriction in response to α1-adrenergic stimulation, both of which could cause epinephrine to have a different effect than in the general population. This systematic review of the literature aimed to investigate if patients with HCM in CA have a detrimental hemodynamic response to epinephrine. A literature search was performed in October 2016 using Medline (OVID), Embase (Elsevier), and Cochrane Library (Wiley). The initial search generated 2429 articles, of which 22 articles were found to meet inclusion criteria: four physiology studies, 13 case reports of hypotensive HCM patients, and five case reports of HCM patients in CA. The reviewed studies demonstrate that epinephrine effect varies in patients with HCM: in some cases, the expected hypertensive effect was obtained, but in others, a paradoxical hypotensive effect, or no effect, was observed. The probable mechanism of this effect is an increased left ventricular outflow tract obstruction. Other drugs were considered in several of these cases. In summary, the retrieved studies jointly suggest that patients with HCM may respond differently to epinephrine than patients without HCM. The suitability of epinephrine in HCM-associated CA is questionable.

Improving Forensic Pathologic Investigation of Sudden Death in the Young: Tools, Guidance, and Methods of Cardiovascular Dissection from the Sudden Death in the Young Case Registry

The Sudden Death in the Young (SDY) Case Registry, a prospective, population-based registry active in ten states, has developed tools to aid pathologists and death investigators in the evaluation and autopsy of unexplained, natural sudden deaths in the pediatric population. The tools were developed by a team of experts representing forensic pathology; pediatric-, cardiac-, and neuropathology; cardiology; neurology/epileptology; pediatrics; genetic counseling; and public health. These tools focus on collecting data relevant to determination of cause of death with a focus on dissection of the cardiovascular system. The tools provide an objective checklist format for ease of use and data extraction. By sharing the tools here and highlighting the examination of the cardiovascular system, the SDY Case Registry encourages a standardized approach to death investigation, autopsy, and data collection for sudden, unexpected deaths in the young towards a goal of informing prevention efforts. Acad Forensic Pathol. 2018 8(2): 347-391.

Controversies Surrounding Exercise in Genetic Cardiomyopathies

Exercise and sports are an integral part of daily life for millions of Americans, with 16% of the US population older than age 15 years engaged in sports or exercise activities (Bureau of Labor statistics). The physical and psychological benefits of exercise are well-recognized. However, high-profile cases of athletes dying suddenly on the field, often due to undiagnosed genetic cardiomyopathies, raise questions about the risks and benefits of exercise for those with cardiomyopathy.

Sudden unexplained cardiac deaths in young adults: a call for multidisciplinary approach

The investigation of death in young (<35 years), previously fit individuals, calls for a detailed autopsy with emphasis placed upon the examination of the heart. In most instances, the cause of cardiac death can be identified during autopsy. However, a large percentage of sudden deaths remain unexplained even after comprehensive medicolegal investigation, including autopsy, and are labelled as autopsy-negative sudden unexplained cardiac death (SUD). Still, when you look to the law, an autopsy, a much needed truth-finding-instrument, usually is not mandatory and is left up to the discretion of various medical or legal authorities, which when making a decision, balance various, often conflicting interests of the state and society on the one hand and of the deceased and his family on the other. Cardiac molecular autopsy calls for a close cooperation between medical examiner, pathologist, family physician, cardiologist, geneticist, and the relatives. Multidisciplinary approach and the identification of genetic cause of SUD enable proper genetic counselling for surviving relatives as well as for implementing specific preventive/therapeutic strategies, e.g. implantable cardioverter-defibrillator (ICD) implantation.

Risk Factors of Sudden Cardiac Death in the Young: Multiple-Year Community-Wide Assessment

BACKGROUND

Prevention of sudden cardiac arrest (SCA) in the young remains a largely unsolved public health problem, and sports activity is an established trigger. Although the presence of standard cardiovascular risk factors in the young can link to future morbidity and mortality in adulthood, the potential contribution of these risk factors to SCA in the young has not been evaluated.

METHODS

We prospectively ascertained subjects who experienced SCA between the ages of 5 and 34 years in the Portland, Oregon, metropolitan area (2002-2015, catchment population ≈1 million). We assessed the circumstances, resuscitation outcomes, and clinical profile of subjects who had SCA by a detailed evaluation of emergency response records, lifetime clinical records, and autopsy examinations. We specifically evaluated the association of standard cardiovascular risk factors and SCA, and sports as a trigger for SCA in the young.

RESULTS

Of 3775 SCAs in all age groups, 186 (5%) occurred in the young (mean age 25.9±6.8, 67% male). In SCA in the young, overall prevalence of warning signs before SCA was low (29%), and 26 (14%) were associated with sports as a trigger. The remainder (n=160) occurred in other settings categorized as nonsports. Sports-related SCAs accounted for 39% of SCAs in patients aged ≤18, 13% of SCAs in patients aged 19 to 25, and 7% of SCAs in patients aged 25 to 34. Sports-related SCA cases were more likely to present with shockable rhythms, and survival from cardiac arrest was 2.5-fold higher in sports-related versus nonsports SCA (28% versus 11%; P=0.05). Overall, the most common SCA-related conditions were sudden arrhythmic death syndrome (31%), coronary artery disease (22%), and hypertrophic cardiomyopathy (14%). There was an unexpectedly high overall prevalence of established cardiovascular risk factors (obesity, diabetes mellitus, hypertension, hyperlipidemia, smoking) with ≥1 risk factors in 58% of SCA cases.

CONCLUSIONS

Sports was a trigger of SCA in a minority of cases, and, in most patients, SCA occurred without warning symptoms. Standard cardiovascular risk factors were found in over half of patients, suggesting the potential role of public health approaches that screen for cardiovascular risk factors at earlier ages.

[Sudden cardiac death : Epidemiology, pathophysiology and risk stratification]

Sudden cardiac death (SCD) remains a major public health burden despite revolutionary progress in the last three decades in the treatment of ventricular tachyarrhythmia with the use of implantable cardioverter defibrillator (ICD) therapy. Survivors of sudden cardiac arrest are at high risk for recurrent tachyarrhythmia events. Early recognition of low left ventricular ejection fractions (≤35%) as a strong predictor of mortality and the causal association between ventricular tachyarrhythmia and SCD has led to a significant development of not only pharmacological antiarrhythmic therapy but also device-based prevention of SCD. The ICD therapy is nowadays routinely used for primary prevention of SCD in patients with significant structural cardiomyopathy and primary electrical arrhythmia syndromes, which are associated with high a risk and secondary prevention in survivors of sudden cardiac arrest. Additionally, effective approaches exist to significantly reduce the recurrence rate of ventricular tachyarrhythmia of various origins by complex electrophysiological endocardial and epicardial catheter ablation procedures.

Higher survival rates in exercise-related out-of-hospital cardiac arrests, compared to non-exercise-related - a study from the Swedish Register of Cardiopulmonary Resuscitation

Background Despite the positive effects of physical activity, the risk of sudden cardiac arrest is transiently increased during and immediately after exercise. The purpose of this study was to assess the incidence of exercise-related out-of-hospital cardiac arrest in the general population and to compare characteristics and prognosis of these cardiac arrests with non-exercise-related out-of-hospital cardiac arrests. Methods Data from all cases of treated out-of-hospital cardiac arrest outside of home reported to the Swedish Register of Cardiopulmonary Resuscitation from 2011-2015 in three counties of Sweden were investigated (population 2.1 m). This registry captures almost 100% of all out-of-hospital cardiac arrests in Sweden. Results Of 1825 out-of hospital cardiac arrests, 137 (7.5%) were exercise-related, resulting in an incidence of 1.2 per 100,000 person-years. The 30-day survival rate was significantly higher among exercise-related out-of hospital cardiac arrests compared to non-exercise-related out-of-hospital cardiac arrests (54.3 % vs 19.4%, p < 0.0001). Patients suffering an exercise-related out-of-hospital cardiac arrest were on average 10 years younger than those who had a non-exercise-related out-of-hospital cardiac arrest, 56.4 years compared to 67.2 years. Exercise-related out-of-hospital cardiac arrests were more often witnessed (89.4% vs 78.6%, p = 0.002), had higher rates of bystander cardiopulmonary resuscitation (80.3% vs 61.0%, p < 0.0001) and were more frequently connected to an automated external defibrillator (20.4% vs 4.6%, p < 0.0001). Conclusions Cardiac arrests that occur in relation to exercise have a significantly better prognosis and outcome than non-exercise-related cardiac arrests. This may be explained by favourable circumstances but may also reflect that these persons experience a sudden cardiac arrest at a lower degree of coronary artery disease, due to their younger age and to exercise being a trigger.

Molecular genetic diagnostics for ventricular arrhythmias and sudden cardiac death syndromes

Inherited forms of ventricular arrhythmias are rare diseases, but a major cause for severe cardiac events, sudden unexplained death syndromes, and death in young adults, infants, and children. Each disorder is genetically heterogeneous (5-20 genes per disease) and molecular testing may include both core genes and less common disease genes as well. Owing to the rapid development and feasibility of sequencing technologies enabling a parallel analysis of several hundred genes up to a whole exome, disease mutations can be identified very efficiently, but have to be seen in the complexity and natural variance of the human genome. Precise phenotypic knowledge and advanced gene variant interpretation are important to ensure adequate patient diagnostics and management. This article focuses on the genetic causes of inherited arrhythmia forms predisposing patients to sudden cardiac death and discusses practical issues and skills for molecular testing.

Etiology of Sudden Death in Sports: Insights From a United Kingdom Regional Registry

BACKGROUND

Accurate knowledge of causes of sudden cardiac death (SCD) in athletes and its precipitating factors is necessary to establish preventative strategies.

OBJECTIVES

This study investigated causes of SCD and their association with intensive physical activity in a large cohort of athletes.

METHODS

Between 1994 and 2014, 357 consecutive cases of athletes who died suddenly (mean 29 ± 11 years of age, 92% males, 76% Caucasian, 69% competitive) were referred to our cardiac pathology center. All subjects underwent detailed post-mortem evaluation, including histological analysis by an expert cardiac pathologist. Clinical information was obtained from referring coroners.

RESULTS

Sudden arrhythmic death syndrome (SADS) was the most prevalent cause of death (n = 149 [42%]). Myocardial disease was detected in 40% of cases, including idiopathic left ventricular hypertrophy (LVH) and/or fibrosis (n = 59, 16%); arrhythmogenic right ventricular cardiomyopathy (ARVC) (13%); and hypertrophic cardiomyopathy (HCM) (6%). Coronary artery anomalies occurred in 5% of cases. SADS and coronary artery anomalies affected predominantly young athletes (≤ 35 years of age), whereas myocardial disease was more common in older individuals. SCD during intense exertion occurred in 61% of cases; ARVC and left ventricular fibrosis most strongly predicted SCD during exertion.

CONCLUSIONS

Conditions predisposing to SCD in sports demonstrate a significant age predilection. The strong association of ARVC and left ventricular fibrosis with exercise-induced SCD reinforces the need for early detection and abstinence from intense exercise. However, almost 40% of athletes die at rest, highlighting the need for complementary preventive strategies.

AMSSM Position Statement on Cardiovascular Preparticipation Screening in Athletes: Current Evidence, Knowledge Gaps, Recommendations and Future Directions

Cardiovascular screening in young athletes is widely recommended and routinely performed prior to participation in competitive sports. While there is general agreement that early detection of cardiac conditions at risk for sudden cardiac arrest and death (SCA/D) is an important objective, the optimal strategy for cardiovascular screening in athletes remains an issue of considerable debate. At the center of the controversy is the addition of a resting electrocardiogram (ECG) to the standard preparticipation evaluation using history and physical examination. The American Medical Society for Sports Medicine (AMSSM) formed a task force to address the current evidence and knowledge gaps regarding preparticipation cardiovascular screening in athletes from the perspective of a primary care sports medicine physician. The absence of definitive outcomes-based evidence at this time precludes AMSSM from endorsing any single or universal cardiovascular screening strategy for all athletes, including legislative mandates. This statement presents a new paradigm to assist the individual physician in assessing the most appropriate cardiovascular screening strategy unique to their athlete population, community needs, and resources. The decision to implement a cardiovascular screening program, with or without the addition of ECG, necessitates careful consideration of the risk of SCA/D in the targeted population and the availability of cardiology resources and infrastructure. Importantly, it is the individual physician's assessment in the context of an emerging evidence-base that the chosen model for early detection of cardiac disorders in the specific population provides greater benefit than harm. AMSSM is committed to advancing evidenced-based research and educational initiatives that will validate and promote the most efficacious strategies to foster safe sport participation and reduce SCA/D in athletes.

Incidence and Etiology of Sudden Cardiac Death: New Updates for Athletic Departments

CONTEXT

Sudden cardiac death (SCD) in a young athlete is a tragic event and is the leading medical cause of death in this population. The precise incidence of SCD in young athletes has been subject of debate, with studies reporting drastically different rates (1:917,000 athlete-years (AYs) to 1:3000 AYs) depending on the methodological design of the investigation or the targeted population.

EVIDENCE ACQUISITION

A literature search was performed in PubMed using the terms: incidence, sudden cardiac death, sudden death, sudden cardiac arrest, etiology, pathology, registry, athlete, young, children, and adolescents. Articles were reviewed for relevance and included if they contained information on the incidence of SCD in athletes or young persons up to the age of 35 years.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

Studies of high quality and rigor consistently yield an incidence of 1:50,000 AYs in college athletes and between 1:50,000 and 1:80,000 AYs for high school athletes, with certain subgroups that appear to be at particularly high risk, including the following: men, basketball players, and African Americans. Initial reports suggest that the most common cause of SCD is hypertrophic cardiomyopathy (HCM). However, more comprehensive investigations in the United States and international populations-athletes, nonathletes, and military-support that the most common finding on autopsy in young individuals with SCD is actually a structurally normal heart (autopsy-negative sudden unexplained death).

CONCLUSION

SCD is the leading cause of death in athletes during exercise and usually results from intrinsic cardiac conditions that are triggered by the physiologic demands of vigorous exercise. Current rates of SCD appear to be at least 4 to 5 times higher than previously estimated, with men, African Americans, and male basketball players being at greatest risk. Emerging data suggest that the leading finding associated with SCD in athletes is actually a structurally normal heart (autopsy-negative sudden unexplained death).

Gender differences in sudden cardiac death in the young-a nationwide study

Background

Hitherto, sudden cardiac death (SCD) in the young has been described with no distinction between genders. SCD occurs more often in men (SCDm) than women (SCDw), but this disparity is not understood and has not been investigated systematically in a nationwide setting. Our objective was to report gender differences in SCD in the young in a nationwide (Denmark) setting.

Methods

All deaths in persons aged 1–35 years nationwide in Denmark between 2000 and 2009 were included. Death certificates and autopsy reports were obtained. The extensive health care registries in Denmark were used to investigate any known disease prior to death. SCDw were compared to SCDm.

Results

During the 10-year study period there were a total of 8756 deaths in 23.7 million person-years. In total, 635 deaths were SCD. SCDw constituted 205 deaths (32%). Women had a higher proportion of witnessed deaths (51 vs. 41%, p = 0.02) and died less often in a public place (16 vs. 26%, p = 0.01). Age at death, ratios of autopsies and sudden unexplained deaths, and comorbidities, did not differ. Causes of SCD were largely comparable between genders. The incidence rate of SCDw was half of that of SCDm (1.8 vs. 3.6 per 100,000 person-years, incidence rate ratio 2.0 (95% CI 1.7–2.4), p < 0.01).

Conclusions

Incidence rate ratio of SCDm vs SCDw is 2. Young SCDw and SCDm are equally investigated, have comparable comorbidity, and causes of SCD. SCD due to potentially inherited cardiac diseases is less often in young women and could reflect a protection of female gender.