Aetiology of sudden cardiac death in athletes in the United Kingdom: a pathological study

Exercise-induced cardiac troponin release in athletes with versus without coronary atherosclerosis

The magnitude of exercise-induced cardiac troponin (cTn) elevations is dependent on cardiovascular health status, and previous studies have shown that occult coronary atherosclerosis is highly prevalent among amateur athletes. We tested the hypothesis that middle-aged and older athletes with coronary atherosclerosis demonstrate greater cTn elevations following a controlled endurance exercise test compared with healthy peers. We included 59 male athletes from the Measuring Athletes' Risk of Cardiovascular events 2 (MARC-2) study and stratified them as controls [coronary artery calcium score (CACS) = 0, n = 20], high CACS [≥300 Agatston units or ≥75th Multi-Ethnic Study of Atherosclerosis (MESA) percentile, n = 20] or significant stenosis (≥50% in any coronary artery, n = 19). Participants performed a cycling test with incremental workload until volitional exhaustion. Serial high-sensitivity cTn (hs-cTn) T and I concentrations were measured (baseline, after 30-min warm-up, and 0, 30, 60, 120, and 180 min postexercise). There were 58 participants (61 [58-69] yr) who completed the exercise test (76 ± 14 min) with a peak heart rate of 97.7 [94.8-101.8]% of their estimated maximum. Exercise duration and workload did not differ across groups. High-sensitivity cardiac troponin T (Hs-cTnT) and high-sensitivity cardiac troponin I (hs-cTnI) concentrations significantly increased (1.55 [1.33-2.14]-fold and 2.76 [1.89-3.86]-fold, respectively) over time, but patterns of cTn changes and the incidence of concentrations >99th percentile did not differ across groups. Serial sampling of hs-cTnT and hs-cTnI concentrations during and following an exhaustive endurance exercise test did not reveal differences in exercise-induced cTn release between athletes with versus without coronary atherosclerosis. These findings suggest that a high CACS or a >50% stenosis in any coronary artery does not aggravate exercise-induced cTn release in middle-aged and older athletes.NEW & NOTEWORTHY Exercise-induced cardiac troponin (cTn) release is considered to be dependent on cardiovascular health status. We tested whether athletes with coronary atherosclerosis demonstrate greater exercise-induced cTn release compared with healthy peers. Athletes with coronary atherosclerosis did not differ in cTn release following exercise compared with healthy peers. Our findings suggest that a high CACS or a >50% stenosis in any coronary artery does not aggravate exercise-induced cTn release in middle-aged and older athletes.

No adverse association between exercise exposure and diffuse myocardial fibrosis in male endurance athletes

The potential association between endurance exercise and myocardial fibrosis is controversial. Data on exercise exposure and diffuse myocardial fibrosis in endurance athletes are scarce and conflicting. We aimed to investigate the association between exercise exposure and markers of diffuse myocardial fibrosis by cardiovascular magnetic resonance imaging (CMR) in endurance athletes. We examined 27 healthy adult male competitive endurance athletes aged 41 ± 9 years and 16 healthy controls in a cross sectional study using 3 Tesla CMR including late gadolinium enhancement and T1 mapping. Athletes reported detailed exercise history from 12 years of age. Left ventricular total mass, cellular mass and extracellular mass were higher in athletes than controls (86 vs. 58 g/m2, 67 vs. 44 g/m2 and 19 vs. 13 g/m2, all p < 0.01). Extracellular volume (ECV) was lower (21.5% vs. 23.8%, p = 0.03) and native T1 time was shorter (1214 ms vs. 1268 ms, p < 0.01) in the athletes. Increasing exercise dose was independently associated with shorter native T1 time (regression coefficient - 24.1, p < 0.05), but expressed no association with ECV. Our results indicate that diffuse myocardial fibrosis has a low prevalence in healthy male endurance athletes and do not indicate an adverse dose-response relationship between exercise and diffuse myocardial fibrosis in healthy athletes.

Sudden Cardiac Death in Young Athletes: JACC State-of-the-Art Review

Athletes epitomize the healthiest segment of society. Despite this premise, sudden cardiac death may occur in apparently healthy athletes, attracting significant attention not only in the medical community but also in laypersons and media. The incidence of sudden cardiac death is variably reported, and epidemiological burden differs among cohorts. Athletes appear to be at risk of developing fatal arrhythmias when harboring a quiescent cardiac disorder. Primary cardiomyopathies, ion channelopathies, and coronary artery anomalies are prevalent causes in young individuals. Cardiac assessment of athletes can be challenging because these individuals exhibit a plethora of electrical, structural, and functional physiological changes that overlap with cardiac pathology. A diagnosis of cardiac disease in a young athlete is not necessarily an indication to terminate competition and sports participation. International guidelines, traditionally focused on disqualification of individuals with cardiac disease, have recently adopted a more liberal attitude, based on a careful assessment of the risk and on a shared-decision making approach.

Cardiac magnetic resonance assessment of athletic myocardial fibrosis; Benign bystander or malignant marker?

The benefits of exercise are irrefutable with a well-established dose-dependent relationship between exercise intensity and reduction in cardiovascular disease. Differentiating the physiological adaptation to exercise, termed the "athlete's heart" from cardiomyopathies, has been advanced by the advent of more sophisticated imaging modalities such as cardiac magnetic resonance imaging (CMR). Myocardial fibrosis on CMR is a mutual finding amongst seemingly healthy endurance athletes and individuals with cardiomyopathy. As a substrate for arrhythmias, fibrosis is traditionally associated with increased cardiovascular risk. In this article, we discuss the aetiologies, distribution and potential implications of myocardial fibrosis in athletes.

Sudden death in young South European population: a cross-sectional study of postmortem cases

To describe the annual incidence and the leading causes of sudden non-cardiac and cardiac death (SCD) in children and young adult Portuguese population. We retrospectively reviewed autopsy of sudden unexpected deaths reports from the Portuguese National Institute of Legal Medicine and Forensic Sciences' database, between 2012 and 2016, for the central region of Portugal, Azores and Madeira (ages 1-40: 26% of the total population). During a 5-year period, 159 SD were identified, corresponding to an annual incidence of 2,4 (95%confidence interval, 1,5-3,6) per 100.000 people-years. Victims had a mean age of 32 ± 7 years-old, and 72,3% were male. There were 70,4% cardiac, 16,4% respiratory and 7,5% neurologic causes of SD. The most frequent cardiac anatomopathological diagnosis was atherosclerotic coronary artery disease (CAD) (33,0%). There were 15,2% victims with left ventricular hypertrophy, with a diagnosis of hypertrophic cardiomyopathy only possible in 2,7%. The prevalence of cardiac pathological findings of uncertain significance was 30,4%. In conclusion, the annual incidence of SD was low. Atherosclerotic CAD was diagnosed in 33,0% victims, suggesting the need to intensify primary prevention measures in the young. The high prevalence of pathological findings of uncertain significance emphasizes the importance of molecular autopsy and screening of first-degree relatives.

Clinical Outcomes in Adult Patients With an Anomalous Right Coronary Artery from the Left Sinus of Valsalva

An anomalous origin of the right coronary artery from the opposite sinus of Valsalva with an intramural course (R-ACAOS-IM) may cause sudden cardiac death in children and adolescents. However, the natural history and management of patients in whom this anomaly is detected later during adulthood remains uncertain. The goals of this study were to assess the impact of an R-ACAOS-IM on the clinical outcomes in an adult population and to determine if adult patients with this anomaly who do not have significant coronary artery disease (CAD) can be managed safely without surgical intervention. A database review identified patients aged >35 years with anomalous coronary arteries diagnosed by cardiac catheterization or coronary computed tomography angiography. The outcomes of patients with R-ACAOS-IM were compared with patients with anomalous left circumflex coronary arteries with retroaortic course (LCx-RA) (an anomaly not associated with ischemic events). The primary outcome was all-cause mortality. The study population consisted of 185 patients aged 59 ± 12 years. Clinical characteristics were similar in the R-ACAOS-IM (n = 88) and LCx-RA (n = 97) groups. At a follow-up of 6.6 ± 4.5 years, there was no difference in mortality (hazard ratio 0.64, 95% confidence interval 0.32 to 1.28, p = 0.20) when adjusted for gender, age, and CAD. A subgroup analysis of 88 patients with no obstructive CAD managed nonoperatively found no difference between the LCx and R-ACAOS-IM groups in mortality (hazard ratio 2.45, 95% confidence interval 0.45 to 13.40, p = 0.30). There was no significant difference between the 2 groups in the composite outcome of death, nonfatal myocardial infarction, or survived cardiac arrest. The outcome of adult patients who have anomalous R-ACAOS-IM are similar to patients who have anomalous LCx-RA with a known benign course. In conclusion, these results suggest that most patients who survive this anomaly into adulthood may be managed conservatively without intervention.

The Lancet Commission to reduce the global burden of sudden cardiac death: a call for multidisciplinary action

Despite major advancements in cardiovascular medicine, sudden cardiac death (SCD) continues to be an enormous medical and societal challenge, claiming millions of lives every year. Efforts to prevent SCD are hampered by imperfect risk prediction and inadequate solutions to specifically address arrhythmogenesis. Although resuscitation strategies have witnessed substantial evolution, there is a need to strengthen the organisation of community interventions and emergency medical systems across varied locations and health-care structures. With all the technological and medical advances of the 21st century, the fact that survival from sudden cardiac arrest (SCA) remains lower than 10% in most parts of the world is unacceptable. Recognising this urgent need, the Lancet Commission on SCD was constituted, bringing together 30 international experts in varied disciplines. Consistent progress in tackling SCD will require a completely revamped approach to SCD prevention, with wide-sweeping policy changes that will empower the development of both governmental and community-based programmes to maximise survival from SCA, and to comprehensively attend to survivors and decedents' families after the event. International collaborative efforts that maximally leverage and connect the expertise of various research organisations will need to be prioritised to properly address identified gaps. The Commission places substantial emphasis on the need to develop a multidisciplinary strategy that encompasses all aspects of SCD prevention and treatment. The Commission provides a critical assessment of the current scientific efforts in the field, and puts forth key recommendations to challenge, activate, and intensify efforts by both the scientific and global community with new directions, research, and innovation to reduce the burden of SCD worldwide.

The Molecular Role of Immune Cells in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a rare and severe condition characterized by chamber dilation and impaired contraction of the left ventricle. It constitutes a fundamental etiology for profound heart failure and abrupt cardiac demise, rendering it a prominent clinical indication for heart transplantation (HTx) among both adult and pediatric populations. DCM arises from various etiologies, including genetic variants, epigenetic disorders, infectious insults, autoimmune diseases, and cardiac conduction abnormalities. The maintenance of cardiac function involves two distinct types of immune cells: resident immune cells and recruited immune cells. Resident immune cells play a crucial role in establishing a harmonious microenvironment within the cardiac tissue. Nevertheless, in response to injury, cardiomyocytes initiate a cytokine cascade that attracts peripheral immune cells, thus perturbing this intricate equilibrium and actively participating in the initiation and pathological remodeling of dilated cardiomyopathy (DCM), particularly during the progression of myocardial fibrosis. Additionally, immune cells assume a pivotal role in orchestrating the inflammatory processes, which are intimately linked to the prognosis of DCM. Consequently, understanding the molecular role of various immune cells and their regulation mechanisms would provide an emerging era for managing DCM. In this review, we provide a summary of the most recent advancements in our understanding of the molecular mechanisms of immune cells in DCM. Additionally, we evaluate the effectiveness and limitations of immunotherapy approaches for the treatment of DCM, with the aim of optimizing future immunotherapeutic strategies for this condition.

Phosphate toxicity and SERCA2a dysfunction in sudden cardiac arrest

Almost half of the people who die from sudden cardiac arrest have no detectable heart disease. Among children and young adults, the cause of approximately one-third of deaths from sudden cardiac arrest remains unexplained after thorough examination. Sudden cardiac arrest and related sudden cardiac death are attributed to dysfunctional cardiac ion-channels. The present perspective paper proposes a pathophysiological mechanism by which phosphate toxicity from cellular accumulation of dysregulated inorganic phosphate interferes with normal calcium handling in the heart, leading to sudden cardiac arrest. During cardiac muscle relaxation following contraction, SERCA2a pumps actively transport calcium ions into the sarcoplasmic reticulum, powered by ATP hydrolysis that produces ADP and inorganic phosphate end products. Reviewed evidence supports the proposal that end-product inhibition of SERCA2a occurs as increasing levels of inorganic phosphate drive up phosphate toxicity and bring cardiac function to a sudden and unexpected halt. The paper concludes that end-product inhibition from ATP hydrolysis is the mediating factor in the association of sudden cardiac arrest with phosphate toxicity. However, current technology lacks the ability to directly measure this pathophysiological mechanism in active myocardium, and further research is needed to confirm phosphate toxicity as a risk factor in individuals with sudden cardiac arrest. Moreover, phosphate toxicity may be reduced through modification of dietary phosphate intake, with potential for employing low-phosphate dietary interventions to reduce the risk of sudden cardiac arrest.

Dilated cardiomyopathy and chronic cardiac inflammation: Pathogenesis, diagnosis and therapy

Dilated cardiomyopathy (DCM) is typically defined by left ventricular dilation and systolic dysfunction in the absence of a clear precipitant. Idiopathic disease is common; up to 50% of patients with DCM have no cause found despite imaging, genetic and biopsy assessments. Treatment remains focused on managing symptoms, reducing the risk of sudden cardiac death and ameliorating the structural and electrical complications of disease progression. In the absence of aetiology-specific treatments, the condition remains associated with a poor prognosis; mortality is approximately 40% at 10 years. The role of immune-mediated inflammatory injury in the development and progression of DCM was first proposed over 30 years ago. Despite the subsequent failures of three large clinical trials of immunosuppressive treatment (ATTACH, RENEWAL and the Myocarditis Treatment Trial), evidence for an abnormal adaptive immune response in DCM remains significant. In this review, we summarise and discuss available evidence supporting immune dysfunction in DCM, with a specific focus on cellular immunity. We also highlight current clinical and experimental treatments. We propose that the success of future immunosuppressive treatment trials in DCM will be dependent on the deep immunophenotyping of patients, to identify those with active inflammation and/or an abnormal immune response who are most likely to respond to therapy.

Mitral Valve Prolapse and Sudden Cardiac Death in Athletes at High Risk

Mitral valve prolapse (MVP) is the most frequent valvulopathy in the general population, with usually a favourable prognosis. Although it can be associated with some complications, ventricular arrhythmias (VA) and sudden cardiac death (SCD) are the most worrying. The estimated risk of SCD in MVP is between 0.2% to 1.9% per year, including MVP patients with and without severe mitral regurgitation (MR). The association between SCD and MVP is expressed by a phenotype called "malignant MVP" characterized by transthoracic echocardiography (TTE) findings such as bileaflet myxomatous prolapse and mitral annulus disjunction (MAD), ECG findings such as repolarization abnormalities, complex ventricular arrhythmias (c-VAs) and LV fibrosis of papillary muscles (PMs) and inferobasal wall visualized by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Therefore, attention is raised for patients with "arrhythmic MVP" characterized from an ECG point of view by frequent premature ventricular contractions (PVCs) arising from one or both PMs as well as by T-wave inversion in the inferolateral leads. In athletes, SCD is the most frequent medical cause of death and in young subjects (< 35 years) usually is due to electrical mechanism affecting who has a silent cardiovascular disease and are not considered per se a cause of increased mortality. In MVP, SCD was reported to happen during sports activity or immediately after and valve prolapse was the only pathological aspect detected. The aim of the present paper is to explore the association between SCD and MVP in athletes, focusing attention on ECG, TTE in particular, and CMR findings that could help to identify subjects at high risk for complex arrhythmias and eventually SCD. In addition, it is also examined if sports activity might predispose patients with MVP to develop major arrhythmias.

Syncope in the athlete - Minor changes, major diagnosis!

We report the case of a 17-year-old athlete who resorted to the emergency department for palpitations and dizziness while exercising. He mentioned two exercise-associated episodes of syncope in the last six months. He was tachycardic and hypotensive. The electrocardiogram showed regular wide complex tachycardia, left bundle branch block morphology with superior axis restored to sinus rhythm after electrical cardioversion. In sinus rhythm, it showed T-wave inversion in V1-V5. Transthoracic echocardiography revealed mild dilation and dysfunction of the right ventricle (RV) with global hypocontractility. Cardiac magnetic resonance (CMR) revealed a RV end diastolic volume indexed to body surface area of 180 ml/m², global hypokinesia and RV dyssynchrony, subepicardial late enhancement in the distal septum and in the middle segment of the inferoseptal wall. The patient underwent a genetic study which showed a mutation in the gene that encodes the desmocolin-2 protein (DSC-2), which is involved in the pathogenesis of arrhythmogenic right ventricular cardiomyopathy (ARVC). According to the modified Task Force Criteria for this diagnosis, the patient presented four major criteria for ARVC. Thus, a subcutaneous cardioverter was implanted, and the patient was followed up at the cardiology department. Arrhythmogenic right ventricular cardiomyopathy diagnosis is based on structural, functional, electrophysiological and genetic criteria reflecting underlying histological changes. This case depicts the essential characteristics for disease recognition.

Risk Factors for Sudden Death in Athletes, Is There a Role for Screening?

Purpose of Review

Sudden cardiac death (SCD) in a young athlete is an infrequent yet devastating event often associated with substantial media attention. Screening athletes for conditions associated with SCD is a controversial topic with debate surrounding virtually each component including the ideal subject, method, and performer/interpreter of such screens. In fact, major medical societies such as the American College of Cardiology/American Heart Association and the European Society of Cardiology have discrepant recommendations on the matter, and major sporting associations have enacted a wide range of screening policies, highlighting the confusion on this subject. This review seeks to summarize the literature in this area to address the complex and disputed subject of screening young athletes for SCD.

Recent Findings

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause myocarditis, which is one acquired cardiac disease associated with SCD. The coronavirus 2019 (COVID-19) pandemic has therefore resulted in an increased incidence of an otherwise less common condition, providing an expanded dataset for further study of this condition. Recent findings indicate that cardiac complications of athletes with myocardial involvement of SARS-CoV-2 infection are rare. Other contemporary work in SCD screening has been focused on the implementation of various screening protocols and measuring their effectiveness.

Summary

No universal consensus exists for athlete screening for conditions associated with SCD with varying guidelines and protocols across cardiology and sport-specific organizations. No screening program will prevent all SCD; however, small programs managed by physicians familiar with the examination of an athlete that carefully personalize screening to the individual may maximize detection of dangerous cardiac conditions while minimizing false positives.

Incidence and Causes of Sudden Cardiac Death in Athletes

Sudden cardiac death (SCD) is the leading cause of medical death in athletes; however, many studies are significantly flawed making an accurate estimation of risk difficult. Incidence studies need to have accurate case ascertainment, a defined study population, and should be stratified by both sex and age. The risk of SCA/d in college-aged males is 1 in 35,000 person-years, black males 1 in 18,000 person-years, and higher-risk sports include men's basketball, men's soccer, and American football. Inherited cardiomyopathies and electrical conditions account for ∼ 2/3 of off SCA/d and can be detected with an ECG. More research is needed to provide more granular estimates.

Role of Cardiac Magnetic Resonance Imaging in the Evaluation of Athletes with Premature Ventricular Beats

Premature ventricular beats (PVBs) in athletes are not rare. The risk of PVBs depends on the presence of an underlying pathological myocardial substrate predisposing the subject to sudden cardiac death. The standard diagnostic work-up of athletes with PVBs includes an examination of family and personal history, resting electrocardiogram (ECG), 24 h ambulatory ECG (possibly with a 12-lead configuration and including a training session), maximal exercise testing and echocardiography. Despite its fundamental role in the diagnostic assessment of athletes with PVBs, echocardiography has very limited sensitivity in detecting the presence of non-ischemic left ventricular scars, which can be revealed only through more in-depth studies, particularly with the use of contrast-enhanced cardiac magnetic resonance (CMR) imaging. The morphology, complexity and exercise inducibility of PVBs can help estimate the probability of an underlying heart disease. Based on these features, CMR imaging may be indicated even when echocardiography is normal. This review focuses on interpreting PVBs, and on the indication and role of CMR imaging in the diagnostic evaluation of athletes, with a special focus on non-ischemic left ventricular scars that are an emerging substrate of cardiac arrest during sport.

Congenital Coronary Artery Anomalies and Sudden Cardiac Death

Coronary artery anomalies (CAAs) are a heterogeneous group of rare congenital diseases whose features and pathophysiological mechanisms are extremely variable, ranging from silent anomalies to sudden cardiac death (SCD) in the most severe cases. Although rare, congenital CAAs confer a high risk of myocardial ischemia and SCD, especially in young, previously "healthy" athletes during or immediately after vigorous exertion. Although some high-risk features that may lead to SCD have been identified, specific pathophysiological mechanisms related to SCD still remain poorly understood. When a CAA is incidentally diagnosed, optimal SCD risk stratification remains challenging, particularly in cases of anomalous aortic origin of a coronary artery arising from the opposite aortic sinus of Valsalva (ACAOS). In recent times, invasive imaging with intravascular ultrasound has gained a role in further identifying high-risk anatomic features; it has been integrated with traditional, non-invasive anatomic imaging evaluations, typically high-quality echocardiography, and cardiac magnetic resonance. Multidisciplinary programs and specific SCD risk scores should be developed in an endeavor to choose the right therapeutic approach, either clinical or interventional/surgical. Intravascular ultrasound is an extremely useful tool to evaluate vessel stenosis, even if prospective studies are still required to further validate this diagnostic strategy. In the present review, we aimed to analyze the pathophysiology and the clinical impact of ACAOS. We also summarized the predominant mechanisms for interference with normal coronary artery function, which might contribute to the onset of life-threatening arrhythmias and SCD.

Run for your life: can exercise be used to effectively target GLUT4 in diabetic cardiac disease?

The global incidence, associated mortality rates and economic burden of diabetes are now such that it is considered one of the most pressing worldwide public health challenges. Considerable research is now devoted to better understanding the mechanisms underlying the onset and progression of this disease, with an ultimate aim of improving the array of available preventive and therapeutic interventions. One area of particular unmet clinical need is the significantly elevated rate of cardiomyopathy in diabetic patients, which in part contributes to cardiovascular disease being the primary cause of premature death in this population. This review will first consider the role of metabolism and more specifically the insulin sensitive glucose transporter GLUT4 in diabetic cardiac disease, before addressing how we may use exercise to intervene in order to beneficially impact key functional clinical outcomes.

Sudden Cardiac Death in Athletes: From the Basics to the Practical Work-Up

Sudden cardiac death in athletes is a relatively rare event, but due to the increasing number of individuals practicing high-performance sports, in absolute terms, it has become an important issue to be addressed. Since etiologies are many and the occurrence is rare, tracing the ideal preparticipation screening program is challenging. So far, as screening tools, a comprehensive clinical evaluation and a simple 12-lead electrocardiogram (ECG) seem to be the most cost-effective strategy. Recent technological advances came to significantly help as second-line investigation tools, especially the cardiac magnetic resonance, which allows for a more detailed ventricular evaluation, cardiac tissue characterization, and eliminates the poor acoustic window problem. This article aims to review all aspects related to sudden cardiac death in athletes, beginning with definitions and epidemiology, passing through etiology and clinical characteristics, then finishing with a discussion about the best ambulatory investigational approach.

Symptoms Preceding Sports-Related Sudden Cardiac Death in Persons Aged 1-49 Years

PURPOSE OF REVIEW

Sports-related sudden cardiac death (Sr-SCD) is a leading natural cause of death in young athletes. To prevent Sr-SCD in athletes, it is important to identify individuals at risk. This review sought to summarize the current knowledge of symptoms prior to Sr-SCD in athletes aged 1-49 years.

RECENT FINDINGS

Cardiovascular screening of athletes is a subject of interest. However, the cost of ECG screening in a young population is relatively high compared to potential benefits, and systematic screening of athletes is heavily debated. In the background population, both cardiac and non-specific symptoms are often present prior to SCD. Both cardiac and non-specific symptoms are present in up to 74% prior to Sr-SCD. The main symptoms are syncope, chest pain, palpitations and dizziness. Knowledge of symptoms could potentially be used in combination with non-invasive prediction models to prevent Sr-SCD and treat athletes at risk.

A Hidden Threat: Anomalous Aortic Origins of the Coronary Arteries in Athletes

Purpose of Review

Anomalous aortic origins of the coronary arteries (AAOCA) are a primary cause of sudden cardiac death in athletes. This review will detail the epidemiology, pathophysiology, and risk stratification of AAOCA, while also highlighting return-to-play considerations for athletes.

Recent Findings

Sport pre-participation cardiovascular screening methods lack sensitivity and specificity in the identification of AAOCA. For the symptomatic athlete, clinicians must maintain a heightened clinical suspicion for AAOCA in order to proceed with appropriate cardiac imaging and functional assessments. Anomalous origin of the left coronary artery with an interarterial course is considered high-risk and requires sport restriction until surgical correction. In contrast, risks associated with anomalous origin of the right coronary artery are controversial, thus management and sports eligibility decisions may incorporate principles of shared-decision making.

Summary

Management options for athletes with AAOCA are complex, requiring a comprehensive clinical evaluation. While advances in multimodality cardiovascular imaging and physiologic functional assessments have improved AAOCA risk stratification, best practice treatment strategies for some AAOCA subtypes remain uncertain. As such, clinical management and sport eligibility decisions require an individualized approach. Future prospective data will guide optimization of treatment strategies for athletes with AAOCA.

Sports-related sudden cardiac death in Spain. A multicenter, population-based, forensic study of 288 cases

INTRODUCTION AND OBJECTIVES

To determine the incidence of sports-related sudden cardiac death in Spain, and to identify the clinical-pathological characteristics, substance abuse, and sports activity associated with this entity.

METHODS

Retrospective, population-based, multicenter study of forensic autopsies conducted in 25 provinces during an 8-year period (2010-2017).

RESULTS

We investigated 288 cases (98.6% occurred in men with a mean age of 43.8±14.4 years). The incidence in the general population was 0.38 cases out of 100 000 inhabitants per year (0.82 among regular athletes), and most cases (54%) occurred in persons aged between 35 and 54 years. The most frequent sports (96% recreational) were cycling (28%), football (18%), and jogging (17%). Death was of cardiovascular origin in 99%. The main causes were ischemic heart disease (63%), cardiomyopathies (21%), and sudden arrhythmic death syndrome (6%). In young people, cardiomyopathies (38%) and ischemic heart disease (30%), present after the age of 20 years, were the most prevalent. The disease was diagnosed during life in 23 cases, relevant clinical antecedents were observed in 30 cases, and cardiovascular risk factors, mainly obesity, in 95 cases. Toxicological analysis detected cardiotoxic substances in 7%, highlighting the association between cannabis and acute ischemic heart disease.

CONCLUSIONS

Sports-related sudden cardiac death in Spain has a very low incidence and affects middle-aged men practicing recreational sports, mainly cycling, football, and jogging. This entity is of cardiovascular origin with early onset of ischemic heart disease. Clinical data and substance abuse should be taken into account to develop preventive strategies.

Etiology of Sudden Cardiac Arrest and Death in US Competitive Athletes: A 2-Year Prospective Surveillance Study

OBJECTIVE

To determine the etiology of sudden cardiac arrest and death (SCA/D) in competitive athletes through a prospective national surveillance program.

DESIGN

Sudden cardiac arrest and death cases in middle school, high school, college, and professional athletes were identified from July 2014 to June 2016 through traditional and social media searches, reporting to the National Center for Catastrophic Sports Injury Research, communication with state and national high school associations, review of the Parent Heart Watch database, and search of student-athlete deaths on the NCAA Resolutions List. Autopsy reports and medical records were reviewed by a multidisciplinary panel to determine the underlying cause.

SETTING AND PARTICIPANTS

US competitive athletes with SCA/D.

MAIN OUTCOME MEASURES

Etiology of SCA/D.

RESULTS

A total of 179 cases of SCA/D were identified (74 arrests with survival, 105 deaths): average age 16.6 years (range 11-29), 149 (83.2%) men, 94 (52.5%) whites, and 54 (30.2%) African American. One hundred seventeen (65.4%) had an adjudicated diagnosis, including 83 deaths and 34 survivors. The most common etiologies included hypertrophic cardiomyopathy (19, 16.2%), coronary artery anomalies (16, 13.7%), idiopathic left ventricular hypertrophy/possible cardiomyopathy (13, 11.1%), autopsy-negative sudden unexplained death (8, 6.8%), Wolff-Parkinson-White (8, 6.8%), and long QT syndrome (7, 6.0%). Hypertrophic cardiomyopathy was more common in male basketball (23.3%), football (25%), and African American athletes (30.3%). An estimated 56.4% of cases would likely demonstrate abnormalities on an electrocardiogram.

CONCLUSIONS

The etiology of SCA/D in competitive athletes involves a wide range of clinical disorders. More robust reporting mechanisms, standardized autopsy protocols, and accurate etiology data are needed to better inform prevention strategies.

Symptoms and healthcare contact preceding sudden cardiac death in persons aged 1-49 years

Sudden Cardiac Death (SCD) is a leading cause of death among persons in their youth and early middle-age. To prevent SCD it is crucial to identify persons at high-risk of SCD. Knowledge of symptoms and medical contact prior to SCD could potentially aid in the identification of high-risk persons in the general population who would benefit from further investigation. This review aims to summarize the current knowledge of symptoms and healthcare contact preceding SCD in persons aged 1-49 years, and to explore how the symptoms differ according to SCD cause and age of the deceased. There was a high frequency of both cardiac and non-specific symptoms prior to SCD. Additionally, many SCD victims contacted the healthcare system prior to death on the basis of their symptoms and only a few were diagnosed with cardiovascular disease. This information underlines that young persons reporting potential cardiac symptoms should also be thoroughly examined. Furthermore, such symptoms could be used in combination with other easily accessible information in non-invasive prediction models aiming at identifying persons at high risk of SCD that would benefit from further investigation and possibly treatment.

Exercise and Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a group of cardiomyopathies associated with ventricular arrhythmias predominantly arising from the right ventricle, sudden cardiac death and right ventricular failure, caused largely due to inherited mutations in proteins of the desmosomal complex. Whilst long recognised as a cause of sudden cardiac death (SCD) during exercise, it has recently been recognised that intense and prolonged exercise can worsen the disease resulting in earlier and more severe phenotypic expression. Changes in cardiac structure and function as a result of exercise training also pose challenges with diagnosis as enlargement of the right ventricle is commonly seen in endurance athletes. Advice regarding restriction of exercise is an important part of patient management, not only of those with established disease, but also in individuals known to carry gene mutations associated with development of ARVC.

Sudden Cardiac Death in Athletes

Sudden cardiac death is a tragedy at any age and under any circumstances but is perhaps most tragic when it claims the life of the athlete, the individual who epitomizes health and a healthy lifestyle. Sports cardiologists from around the world have worked to quantitate the incidence of sudden cardiac death (SCD) in the athlete, to identify risk factors, to develop pre-participation screening tools, and to formulate plans to deal with on-field SCD. Progress has been made, but much remains to be done in order to make both competitive and recreational sports safer for both patients with known cardiac disease and athletes without known or suspected cardiac abnormalities.

Significance of automated external defibrillator in identifying lethal ventricular arrhythmias

Automated electrical defibrillator (AED) is critical in saving children who develop unexpected cardiac arrest (CA), but its diagnostic capacity is not fully acknowledged. Retrospective cohort study of patients with aborted sudden cardiac death (SCD) was performed. Twenty-five patients (14 males) aged 1.3 to 17.5 years who presented with CA survived with prompt cardiopulmonary resuscitation. Eighteen patients had no prior cardiac diagnosis. Cardiac arrest occurred in 10 patients with more than moderate exercise, in 7 with light exercise, and in 8 at rest (including one during sleep). Twenty-two patients were resuscitated with AED, all of which were recognized as a shockable cardiac rhythm. Thorough investigations revealed 6 ion channelopathies (4 catecholaminergic polymorphic ventricular tachycardia, one long QT syndrome, and one Brugada syndrome), 5 congenital heart disease (including 2 with coronary artery obstruction), 6 cardiomyopathies, 2 myocarditis, and 2 miscellaneous. Four patients had no identifiable heart disease. In 5 patients, the downloaded AED-recorded rhythm strip delineated the underlying arrhythmias and their responses to electrical shocks. Four patients who presented with generalized seizure at rest were initially managed for seizure disorder until AED recording identified lethal ventricular arrhythmias.Conclusions: AED reliably identifies the underlying lethal ventricular arrhythmias in addition to aborting SCD. What is Known: • Although infrequent in children, sudden cardiac death (SCD) is often an unexpected and tragic event. The etiology is diverse and sometimes remains unknown despite extensive investigations. • Automated external defibrillator (AED) is both therapeutic in aborting SCD and diagnostic in identifying the underlying lethal ventricular arrhythmias. However, the diagnostic aspect of AED is under-acknowledged by most medical providers. What is New: • Four of 25 patients (16%) were initially managed for possible seizure disorders until AED recording identified lethal ventricular arrhythmia. • The AED recording of the lethal arrhythmia during cardiopulmonary resuscitation (CPR) should always be obtained as it plays a crucial role in the decision-making process before ICD implantation. All medical providers should become familiar with downloading cardiac rhythm strips from AED when requested.

Sports-related sudden cardiac death due to myocardial diseases on a population from 1-35 years: a multicentre forensic study in Spain

This is a multicentre forensic study that identifies all sports-related sudden deaths (SRSDs) in young people, due to myocardial diseases (MDs) that occurred in a large area of Spain. The aim of the study is to assess the epidemiology, causes of death, and sport activities associated with these fatalities. This is a retrospective study based on forensic autopsies performed in the provinces of Biscay, Seville, Valencia and in the jurisdiction covered by the National Institute of Toxicology and Forensic Sciences in Madrid (Spain). The retrospective study encompasses from 2010 to 2017. All sudden cardiac deaths (SCDs) in persons 1-35 years old were selected. The total number of SCDs were divided into death occurred during exercise (SRSD) and death during rest, sleep or normal activities (non-SRSD). Each of these two groups was subdivided according to the cause of death into MD (primary cardiomyopathies and myocarditis) and non-MD. Clinic-pathological, toxicological and genetic characteristics of SRSD due to MD were analysed. Over the 8-year study period, we identified 645 cases of SCD in the young: 75 SRSD (11.6%) and 570 non-SRSD (88.4%). MD was diagnosed in 33 (44.0%) of the SRSD and in 112 (19.6%) of the non-SRSD cases. All cases of SRSD due to MD were males (mean age (24.0 ± 7.6) years) practicing recreational sports (85%). SRSDs were more frequent in arrhythmogenic cardiomyopathy (ACM) (37%) and hypertrophic cardiomyopathy (HCM) (24%), followed by myocarditis (15%) and idiopathic left ventricular hypertrophy (ILVH) (9%). Only in five cases of SRSD the MD responsible of death (HCM) had been diagnosed in life. Cardiovascular symptoms related to the disease were present in other seven patients (six of them with ACM). Postmortem genetic studies were performed in 15/28 (54%) primary cardiomyopathies with positive results in 12 (80%) cases. The most frequent sports disciplines were football (49%) followed by gymnastics (15%) and running (12%). In Spain, SRSD in young people due to MDs occurs in males who perform a recreational activity. Compared with control group we observed a strong association between MDs and exertion. One in three SRSDs are due to cardiomyopathy, especially ACM, which reinforces the need for preparticipation screening to detect these pathologies in recreational sport athletes. Further studies are warranted to understand the causes and circumstances of sudden death to facilitate the development of preventive strategies.

Primary Myocardial Fibrosis as an Alternative Phenotype Pathway of Inherited Cardiac Structural Disorders

BACKGROUND

Myocardial fibrosis is a common postmortem finding among young individuals with sudden cardiac death. Because there is no known single cause, we tested the hypothesis that some cases of myocardial fibrosis in the absence of identifiable causes (primary myocardial fibrosis [PMF]) are associated with genetic variants.

METHODS

Tissue was obtained at autopsy from 4031 consecutive individuals with sudden cardiac death in Northern Finland, among whom PMF was the only structural finding in 145 subjects with sudden cardiac death. We performed targeted next-generation sequencing using a panel of 174 genes associated with myocardial structure and ion channel function when autopsies did not identify a secondary basis for myocardial fibrosis. All variants with an effect on protein and with a minor allele frequency <0.01 were classified as pathogenic or variants of uncertain significance on the basis of American College of Medical Genetics consensus guidelines.

RESULTS

Among the 96 specimens with DNA passing quality control (66%), postmortem genetic tests identified 24 variants of known or uncertain significance in 26 subjects (27%). Ten were pathogenic/likely pathogenic variants in 10 subjects (10%), and 14 were variants of uncertain significance in 11 genes among 16 subjects (17%). Five variants were in genes associated with arrhythmogenic right ventricular cardiomyopathy, 6 in hypertrophic cardiomyopathy-associated genes, and 11 in dilated cardiomyopathy-associated genes; 2 were not associated with these disorders. Four unique variants of uncertain significance cosegregated among multiple unrelated subjects with PMF. No pathogenic/likely pathogenic variants were detected in ion channel-encoding genes.

CONCLUSIONS

A large proportion of subjects with PMF at autopsy had variants in genes associated with arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, and hypertrophic cardiomyopathy without autopsy findings of those diseases, suggesting that PMF can be an alternative phenotypic expression of structural disease-associated genetic variants or that risk-associated fibrosis was expressing before the primary disease. These findings have clinical implications for postmortem genetic testing and family risk profiling.

Sudden death related cardiomyopathies - Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a form of inherited cardiomyopathy. Most individuals with HCM experience minimal symptoms throughout their lifetime. However, those with HCM are at risk of ventricular arrhythmias and sudden cardiac death (SCD), the most feared complication of HCM. Implantable cardioverter defibrillator (ICD) implantation has played a large role in transforming this disease from one with an ominous prognosis to one with mortality rates that are on par with the general public. Since the early 2000s, balance between SCD prevention and unnecessary ICD placement has been sought, this is reflected in the evolution of SCD risk stratification models for patients with HCM. This review discusses key concepts pertaining to HCM, with emphasis on prevention of SCD, and summarizes and compares the recommendations for ICD implantation in current guidelines.

Anomalous Coronary Artery Origin and Sudden Cardiac Death: Clinical and Pathological Insights From a National Pathology Registry

OBJECTIVES

This study sought to describe the clinical and pathological features of anomalous origin of a coronary artery (AOCA) in sudden cardiac death (SCD) victims.

BACKGROUND

AOCA from the inappropriate sinus of Valsalva or from the pulmonary artery is increasingly diagnosed with current imaging techniques. AOCA is a possible cause of SCD.

METHODS

We reviewed a database of 5,100 consecutive cases of SCD referred to our specialist cardiac pathology center between January 1994 and March 2017 and identified a subgroup of 30 cases (0.6%) with AOCA. All cases underwent detailed post-mortem evaluation including histological analysis by an expert cardiac pathologist. Clinical information was obtained from referring coroners.

RESULTS

The mean age was 28 ± 16 years and 23 individuals were male (77%). In 8 cases (27%), SCD occurred before 18 years of age. Cardiac symptoms were present in 11 individuals (37%), and syncope was the most common (n = 6, 20%). Anomalous left coronary artery arising from the right sinus of Valsalva (ALCA) with interarterial course (n = 11) and anomalous right coronary artery arising from the left sinus of Valsalva (ARCA) with interarterial course (n = 11) were the most common found. ALCA arising from pulmonary artery was present in 7 cases, whereas in 1 case, the left coronary artery arose from the noncoronary cusp. Left ventricular fibrosis was reported in 11 cases (37%) and was mainly subendocardial. There was evidence of acute infarction in 2 cases. Death occurred during exercise or emotional stress in 15 (50%) cases. The AOCA variant where death occurred more frequently during physical activity was ALCA (8 of 11, 73%), followed by ALCA arising from pulmonary artery (4 of 7, 57%) and ARCA (2 of 11, 18%).

CONCLUSIONS

AOCA is a rare cause of SCD. ALCA and ARCA with interarterial course are the most common anatomical variants recognized at the postmortem of SCD victims. ALCA is more commonly associated with death during exercise. Cardiac arrhythmias causing sudden death seem most likely in the cases without overt myocardial damage.

Cardiac Screening of Young Athletes: a Practical Approach to Sudden Cardiac Death Prevention

PURPOSE OF REVIEW

We aim to report on the current status of cardiovascular screening of athletes worldwide and review the up-to-date evidence for its efficacy in reducing sudden cardiac death in young athletes.

RECENT FINDINGS

A large proportion of sudden cardiac death in young individuals and athletes occurs during rest with sudden arrhythmic death syndrome being recognised as the leading cause. The international recommendations for ECG interpretation have reduced the false-positive ECG rate to 3% and reduced the cost of screening by 25% without compromising the sensitivity to identify serious disease. There are some quality control issues that have been recently identified including the necessity for further training to guide physicians involved in screening young athletes. Improvements in our understanding of young sudden cardiac death and ECG interpretation guideline modification to further differentiate physiological ECG patterns from those that may represent underlying disease have significantly improved the efficacy of screening to levels that may make screening more attractive and feasible to sporting organisations as a complementary strategy to increased availability of automated external defibrillators to reduce the overall burden of young sudden cardiac death.

A 10-year review of sudden death during sporting activities

BACKGROUND

Sudden death during sport is a rare but devastating event. Previous research has mostly focused on sudden deaths in young competitive athletes.

OBJECTIVE

The purpose of this study was to characterize the demographics and etiologies of sudden cardiac death during sport in Australia.

METHODS

All autopsies conducted at our forensic medicine facility between 2006 and 2015 inclusive were reviewed. Sporting-related deaths among those 7-65 years of age were identified. Data collected included subject height, weight, gender, circumstances of death, and pathologic findings at autopsy.

RESULTS

A total of 19,740 autopsies were completed in the study period: 12,395 in subjects age 18-65 years (adults) and 385 in subjects age 7-17 years (children). There were 201 sports-related adult deaths at an incidence rate of 0.76-1.49 per 100,000 participant-years. Of the deaths, 74% were witnessed. Of the adult cases, 68% (n = 136) were due to cardiac causes, with coronary artery disease the most frequent cause (n = 90 [45%]). Structural abnormalities were common in adult cardiac deaths; 51 (38%) had cardiac weight ≥500 g, and 75 (55%) had left ventricular wall thickness >15 mm. Of the 15 child deaths, 5 (33%) were arrhythmogenic or presumed arrhythmic, and 5 (33%) were inherited cardiomyopathies (2 hypertrophic cardiomyopathy, 3 arrhythmogenic right ventricular cardiomyopathy).

CONCLUSION

Sudden cardiac death during sport is rare. Deaths are mostly due to coronary artery disease in adults and cardiomyopathy or arrhythmia in children. Because the majority of sports deaths are witnessed, they present an opportunity to enhance outcomes by cardiopulmonary resuscitation training and increased availability of automated external defibrillators at sports venues.

Inherited cardiomyopathies and sports participation

Competitive sports activity is associated with an increased risk of sudden cardiovascular death in adolescents and young adults with inherited cardiomyopathies. Many young subjects aspire to continue competitive sport after a diagnosis of cardiomyopathy and the clinician is frequently confronted with the problem of eligibility and the request of designing specific exercise programs. Since inherited cardiomyopathies are the leading cause of sudden cardiovascular death during sports performance, a conservative approach implying disqualification of affected athletes from most competitive athletic disciplines is recommended by all the available international guidelines. On the other hand, we know that the health benefits of practicing recreational sports activity can overcome the potential arrhythmic risk in these patients, provided that the type and level of exercise are tailored on the basis of the specific risk profile of the underlying cardiomyopathy. This article will review the available evidence on the sports-related risk of sudden cardiac death and the recommendations regarding eligibility of individuals affected by inherited cardiomyopathies for sports activities.

Obesity and sudden cardiac death in the young: Clinical and pathological insights from a large national registry

Aims Obesity is an increasing public health problem and a risk factor for cardiovascular diseases. The aim of the study was to determine the main features and aetiologies in a large cohort of sudden cardiac deaths that occurred in obese subjects. Methods Between 1994 and 2014, 3684 consecutive cases of unexpected sudden cardiac death were referred to our cardiac pathology centre. This study was confined to young individuals (age ≤ 35 years) for whom information about body mass index was available and consisted of 1033 cases. Results Two-hundred and twelve individuals (20%) were obese. In obese sudden cardiac death victims the main post-mortem findings were: normal heart (sudden arrhythmic death syndrome) ( n = 108; 50%), unexplained left ventricular hypertrophy ( n = 25; 12%) and critical coronary artery disease ( n = 25; 12%). Less common were hypertrophic cardiomyopathy ( n = 4; 2%) and arrhythmogenic right ventricular cardiomyopathy ( n = 4;2%). When compared with non-obese sudden cardiac death victims, sudden arrhythmic death syndrome was less common (50% vs. 60%, P < 0.01), whereas left ventricular hypertrophy and critical coronary artery disease were more frequent (12% vs. 2%, P < 0.001 and 12% vs. 3%, P < 0.001, respectively). The prevalence of critical and non-critical coronary artery disease was significantly higher in obese individuals (23% vs. 10% in non-obese individuals, P < 0.001). Conclusions Various conditions underlie sudden cardiac death in obesity, with a prevalence of sudden arrhythmic death syndrome, left ventricular hypertrophy and coronary artery disease. The degree of left ventricular hypertrophy measured by heart weight is excessive even after correction for body size. Almost one in four young obese sudden death patients show some degree of coronary artery disease, underscoring the need for primary prevention in this particular subgroup.

Shocking the system: AEDs in military resuscitation

Automated external defibrillator (AED) devices have been in routine clinical use since the early 1990s to deliver life-saving shocks to appropriate patients in non-clinical environments. As expectations of survival from out-of-hospital cardiac arrest increase, and evidence incontrovertibly points to reduced timelines as the most crucial factor in achieving return of spontaneous circulation, questions regarding the availability and location of AEDs in the UK military need to be readdressed. This article explores the background of AEDs and reviews their history, life-saving potential and defines current and best practice. It goes on to review the evidence surrounding training and looks to identify knowledge gaps that might be addressed effectively by future research. Finally, it makes recommendations regarding training, availability of AEDs on military bases and locations most likely to deliver good outcomes for military personnel in the future.

[Effect of intermittent variable intensity exercise on QT variation and risk of sudden cardiac death among Cameroonian school adolescents]

INTRODUCTION

Several cases of sudden deaths are observed among students practicing sport and physical activity (SPA). Just few studies have been carried out on the variation of the QT (interval) and risk of sudden death during sporting exercises.

AIM

To determine the effect of variable intermittent stress intensity on the variation of QT and the risk of sudden cardiac death.

PATIENTS AND METHODS

Form 4, lower sixth and upper sixth students were recruited from a high school in Douala (Cameroon). Each subject was tested; starting with a 2-km walk followed by a sprint race or an endurance race, protocol I (P1) or the reverse; protocol II (P2). Two electrocardiograms were recorded; prior to the beginning of the SPA and 5minutes after the last race. QT was corrected using four formulas.

RESULTS

Forty-one subjects (21 women and 20 men), mean age 18±2 years were recruited. At the end of the exercise, corrected QT increased with Bazzet's formula and decreased with Frahmingam's formula. The difference was not significant with Fridericia and Hodges formulas. The frequency of long QT was higher at the end of the exercise with Bazzet's formula (12.2% vs. 24.4%, P=0.009) while the difference was not significant for the other formulas.

CONCLUSION

The risk of sudden cardiac death increases significantly after SPA. More studies on large samples are needed.