Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program

[Sudden cardiac death. Selected forensic aspects]

Sudden cardiac death is one of the most common causes of death and a significant number of sudden deaths occurs especially in young people. Sudden cardiac death is also frequently represented in forensic autopsy practice. In such cases pathological findings in the heart can often explain the reason for the acute death. These pathological changes include not only myocardial infarction, coronary thrombosis and all forms of myocarditis/endocarditis but also rare diseases, such as hereditary structural or arrythmogenic anomalies, lesions of the cardiac conduction system or primary cardiac tumors.

In vitro functional analyses of arrhythmogenic right ventricular cardiomyopathy-associated desmoglein-2-missense variations

Background

Although numerous sequence variants in desmoglein-2 (DSG2) have been associated with arrhythmogenic right ventricular cardiomyopathy (ARVC), the functional impact of new sequence variations is difficult to estimate.

Methodology/Principal Findings

To test the functional consequences of DSG2-variants, we established an expression system for the extracellular domain and the full-length DSG2 using the human cell line HT1080. We established new tools to investigate ARVC-associated DSG2 variations and compared wild-type proteins and proteins with one of the five selected variations (DSG2-p.R46Q, -p.D154E, -p.D187G, -p.K294E, -p.V392I) with respect to prodomain cleavage, adhesion properties and cellular localisation.

Conclusions/Significance

The ARVC-associated DSG2-p.R46Q variation was predicted to be probably damaging by bioinformatics tools and to concern a conserved proprotein convertase cleavage site. In this study an impaired prodomain cleavage and an influence on the DSG2-properties could be demonstrated for the R46Q-variant leading to the classification of the variant as a potential gain-of-function mutant. In contrast, the variants DSG2-p.K294E and -p.V392I, which have an arguable impact on ARVC pathogenesis and are predicted to be benign, did not show functional differences to the wild-type protein in our study. Notably, the variants DSG2-p.D154E and -p.D187G, which were predicted to be damaging by bioinformatics tools, had no detectable effects on the DSG2 protein properties in our study.

Diagnosis and management of sudden death in children

PURPOSE OF REVIEW

Sudden death is a leading cause of death in industrialized nations. Sudden death in children represents a relatively small proportion of sudden death in the population, but has devastating effects on families and communities, and often attracts significant attention.

RECENT FINDINGS

Several recent studies show that a portion of previously unexplained sudden death in children is due to cardiac conditions which are potentially identifiable by 'molecular autopsy' or investigation of family members. As some of these conditions that may present with sudden death can be detected by ECG, the controversial role of screening asymptomatic children will be discussed, as will the question of increased risk associated with stimulant medications. Recent pharmacologic and nonpharmacologic advancements for those with identifiable conditions at increased risk of sudden death will be reviewed.

SUMMARY

Recent developments have refined our understanding of the various causes of sudden death in children. Post-mortem genetic testing and/or investigation of family members can be fruitful in determining a cause and identifying at-risk relatives. Given the available and potential treatments for specific disorders with increased risk of sudden death, the benefit of identifying such disorders early is clear. The debate regarding universal ECG screening is social and political, as well as scientific.

Significance of false negative electrocardiograms in preparticipation screening of athletes for hypertrophic cardiomyopathy

Preparticipation screening of athletes with 12-lead electrocardiography has been promoted for the detection of asymptomatic cardiovascular disease, particularly hypertrophic cardiomyopathy (HC). Although false-positive electrocardiographic (ECG) results for HC are well recognized in athlete screening, expected false-negative rates are unknown. The aim of this study was to characterize the rate of false-negative ECG findings in a cohort of young asymptomatic patients with phenotypically expressed HC, defined by cardiovascular magnetic resonance, using the 2010 European Society of Cardiology recommended ECG criteria for the identification of suspected heart disease in trained athletes. Cardiac magnetic resonance studies and 12-lead electrocardiography were performed in 114 consecutive asymptomatic patients with HC aged ≤35 years (mean age 22 ± 8 years; 77% male patients). Electrocardiograms were analyzed to distinguish pathologic ECG patterns from alterations considered nonpathologic and physiologic consequences of athletic training. Among the 114 patients with HC, 103 (90%) demonstrated ≥1 pathologic ECG abnormality, while the remaining 11 patients (10%) had normal or nonpathologic ECG patterns and therefore defined a subgroup in whom ECG screening would not be expected to raise suspicion of heart disease (i.e., false-negative results). In this false-negative ECG results group, maximal left ventricular wall thickness was 17 ± 2 mm (range 15 to 21), compared to patients with pathologic ECG patterns, in whom maximal left ventricular wall thickness was 22 ± 5 mm (p = 0.003). In conclusion, a substantial minority of young asymptomatic patients with HC with phenotypically expressed left ventricular hypertrophy have nonpathologic ECG findings on the basis of the 2010 European Society of Cardiology guidelines. In principle, this high false-negative rate of 10% represents an important limitation in applying 12-lead electrocardiography to large, apparently healthy athletic populations for the detection of HC.

Can an athlete have too much ticker? Hypertrophic cardiomyopathy in young athletes

Sudden cardiac death (SCD) is an uncommon but devastating potential consequence of participation in competitive sport. It is seen in adolescent and young adult athletes. The most common cause of this, hypertrophic cardiomyopathy (HCM), is a genetic disorder responsible for more than a third of cases and is manageable. Screening is undertaken for HCM, using differing strategies in Europe and North America. Screening and early diagnosis have reduced the mortality rate but has come at a significant economic cost. The evidence and relevant arguments for and against screening are presented together with management strategies as reflected by an illustrative case.

Anomalous aortic origin of coronary arteries from the opposite sinus: a critical appraisal of risk

Background

Anomalous aortic origin of the coronary artery (AAOCA) from the opposite sinus of Valsalva with an interarterial course has received much attention due to its association with sudden death in otherwise healthy individuals. AAOCA is relatively common and may have significant public health implications. While our knowledge of its pathophysiology and natural history remains incomplete, an emphasis has been placed on surgical correction.

Discussion

In 2005 we published a review examining the rates of sudden death with AAOCA, as well as complications of surgical management. Evidence now points even more strongly to lower rates of sudden death, while surgical outcomes data now better documents associated risks.

Summary

Armed with this updated information, we agree with the need for a national registry to better track patients with AAOCA. We submit that the risks of surgical management outweigh any benefits in the asymptomatic patient with anomalous right coronary artery, and expectant management should also be strongly considered even in asymptomatic patients with anomalous left coronary artery.

Cardiovascular health, part 1: preparticipation cardiovascular screening

CONTEXT

Identification of potentially fatal cardiac conditions in otherwise healthy athletes presents a major challenge to the sports medicine community. The requirements for preparticipation screening vary among countries and even from state to state within the United States. The mandated use of an electrocardiogram as a screening implement has provoked international controversy.

EVIDENCE ACQUISITION

Part 1 of this review highlights the current guidelines and controversies surrounding cardiovascular screening, with a focus on the diagnostic challenges associated with identifying athletes with inheritable cardiomyopathies. Data sources were limited to peer-reviewed publications from 1984 to the present.

RESULTS

Preparticipation screening should include at least a history and a physical examination for all athletes, whereas use of an electrocardiogram is still controversial. Diagnosis of inherited cardiomyopathies presents unique challenges, particularly in hypertrophic cardiomyopathy, where many features can mimic those found in the "athlete's heart."

CONCLUSIONS

Recognizing cardiac conditions in athletes that can predispose them to sudden cardiac death or other adverse outcomes is of vital importance, as is the appropriate exclusion of these athletes from competition. Further studies are needed to determine the most efficient and cost-effective means of screening and to increase the sensitivity and specificity of diagnostic testing for inheritable cardiovascular diseases.

ECG and echocardiographic findings in 10-15-year-old elite athletes

BACKGROUND

Data on electrocardiographic and echocardiographic pre-participation screening findings in paediatric athletes are limited.

METHODS AND RESULTS

10--15 year-old athletes (n = 343) were screened using electro- and echocardiography. The electrocardiogram (ECG) was normal in 220 (64%), mildly abnormal in 108 (31%), and distinctly abnormal in 15 (4%) athletes. Echocardiographic upper reference limits (URL, 97.5 percentile) for the left ventricular (LV) wall thickness in 10-11-year-old boys and girls were 9-10 mm and 8-9 mm, respectively; in 12-13-year-old boys and girls 9-10 mm; and in 14-15-year-old boys and girls 10-11 mm and 9-10 mm, respectively. Three athletes were excluded from competitive sports: one for symptomatic Wolff-Parkinson-White syndrome with a normal echocardiogram; one for negative T-waves in V1-V4 and a dilated right ventricle by echocardiography suggestive of (arrhythmogenic) right ventricular disease; and one for normal ECG and biscupid aortic valve including an aneurysm of the ascending aorta detected by echocardiography. Related to echocardiographic findings, the sensitivity and specificity of the ECG to identify cardiovascular abnormalities was 38% and 64%, respectively. The ECG's positive-predictive and negative-predictive values were 13% and 88%, respectively. The numbers needed to screen and calculated costs were 172 for ECG (€7049), 172 for echocardiography (€11,530), and 114 combining ECG and echocardiography (€9323).

CONCLUSIONS

Compared to adults, paediatric athletes presented with fewer distinctly abnormal ECGs, and there was no gender difference in paediatric athletes' ECG-pattern distribution. A combination of ECG and echocardiography for pre-participation screening of paediatric athletes is superior to ECG alone but 30% more costly.

[Sudden death during sport activity in Tunisia: autopsy study in 32 cases]

PURPOSE

To develop profile of the victims and to study circumstances, causes of death and autopsy findings.

METHODS

Retrospective study of cases of sudden death in sport activity whose autopsy was performed in forensic department of Tunis, between January 2005 and December 2009.

RESULTS

During study period, 32 cases of SD in sport activity were recorded. These are amateur athletes predominantly male (84% of cases). Victims are aged between 15 and 79 years with an average age of about 33.16 years. Young subjects whose age is less than 35 years representing 68.7% of cases. 9.3% of victims had a family history of SD and 18.7% of cases had a known cardiac history. The sports most involved are running (40.6% of cases), football (31.3% of cases) and dance (12.5% of cases). Sixty-nine percent of victims died during sports activities. Presence of witnesses was noted in all cases; however, none of these witnesses has begun resuscitation. Cause of death was cardiac in 84.4% of cases. In young athletes, hypertrophic cardiomyopathy is the leading cause (nine cases), followed by arrhythmogenic right ventricular dysplasia (three cases). Among other causes, there is the myocardial bridge, congenital anomalies of the coronary arteries, aortic dissection and dilated cardiomyopathy. Beyond 35 years, coronary artery diseases represent the cause of death (nine cases). Only case of death secondary to non-cardiac disease occurred after a severe asthma attack. In four cases (12.5%), no cause of death was identified after a complete autopsy accompanied by further investigations. The cause of the death was imputed to a rhythmic pathology.

CONCLUSION

This is the first study dealing with autopsy in SD in sport have provided a specific profile of victims. Other studies on larger samples and using standardized autopsy protocols are needed.

Twelve-lead electrocardiography in the young: physiologic and pathologic abnormalities

BACKGROUND/ OBJECTIVE: The purpose of the present study was to analyze the prevalence of physiologic and pathologic ECG abnormalities in a cohort of young conscripts that represents the whole young generation of today.

METHODS

ECGs of all Swiss citizens who underwent conscription for the army during a 29-month period were analyzed manually.

RESULTS

ECGs of 43,401 conscripts (mean age 19.2 ± 1.1 years) were analyzed; 158 conscripts were female. Incomplete right bundle branch block was found in 5870 (13.5%) and left anterior fascicular block in 360 (0.83%). First-degree AV block was present in 329 (0.8%) and Mobitz type I (Wenckebach) second-degree AV block in 3 (0.01%). Early repolarization was observed in 1035 (2.4%), T-wave inversion in 39 (0.09%), and minor T-wave changes in 182 (0.42%). Brugada-like abnormalities were observed in 6 (0.01%). None of the conscripts had atrial fibrillation or flutter.

CONCLUSION

ECG abnormalities can be found in a relatively large proportion of young individuals. Incomplete right bundle branch block, left fascicular block, and first-degree AV block are the most frequent findings. No conscript presented with atrial fibrillation or flutter.

Can preload-reducing therapy prevent disease progression in arrhythmogenic right ventricular cardiomyopathy? Experimental evidence and concept for a clinical trial

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy and a leading cause of sudden cardiac death in a young population. ARVC is especially common in young athletes. Mutations in different desmosomal genes have been identified causing dysfunctional cell-cell contacts. Reduced myocardial expression of plakoglobin in cell-cell contact complexes appears to associate with disease manifestation in patients harbouring mutations within other cell-cell contact genes. Experimental data suggest that preload reduction may be a simple and effective intervention to prevent disease progression and ventricular arrhythmias in ARVC. This review discusses the potential effects of this innovative approach and describes the design of the first controlled trial of preload-reducing therapy in patients with ARVC.

Sudden cardiac death in young athletes; a literature review and special considerations in Asia

Sudden cardiac death (SCD) in a young athlete is rare, but catastrophic. Exercise acts as a risk factor for SCD in people with cardiovascular disease. A diversity of cardiovascular disorders including hypertrophic cardiomyopathy, congenital coronary anomalies, arrhythmogenic right ventricular dysplasia, dilated cardiomyopathy, aortic rupture due to Marfan syndrome, myocarditis, valvular disease and electrical disorders (Wolff–Parkinson–White syndrome, long QT syndrome, Brugada syndrome), as well as commotio cordis represent the common causes of SCD in young athletes.

As the outcome of lethal cardiovascular disorders is not reversible except in few cases, effective measures should be addressed to reduce the burden of sudden cardiac death in young athletes. Currently, two types of recommendations are proposed by American and European countries.

It seems that there are some special considerations in Asia, entirely different from North America or Europe, which warrant more comprehensive research on epidemiology and etiology of SCD in young Asian athletes by country and evaluation of current national preventive strategies and their achievements in decreasing the risk. Using these data and considering regional restrictions, an expert group will be able to plan a practical and feasible preventive strategy.

Sudden death in athletes

Sudden cardiac death in an athlete is a rare and heartrending event, often occurring in the absence of warning symptoms. The causes of sudden cardiac death in athletes are age dependent and demonstrate a degree of geographical variation. Pre-participation screening is recommended by both the European Society of Cardiology and the American Heart Association although there is no consensus regarding the utilisation of an electrocardiogram. This article will review the aetiology of sudden cardiac death and will present the evidence for pre-participation screening.

Costs and benefits of targeted screening for causes of sudden cardiac death in children and adolescents

BACKGROUND

Sudden cardiac death in children is a rare but devastating event. Experts have debated the merits of community-based screening programs using an ECG and targeting 2 potential high-risk groups: school-aged children initiating stimulant medications to treat attention-deficit/hyperactivity disorder and adolescents participating in sports.

METHODS AND RESULTS

Simulation models incorporating detailed prevalence, sensitivity and specificity, and treatment algorithms were built to determine the cost-effectiveness of targeted sudden cardiac death screening. Clinical care algorithms were constructed for asymptomatic children initiating stimulants for attention-deficit/hyperactivity disorder (8 years of age) or participating in sports (14 years of age) and presenting with a positive ECG finding suggestive of 1 of the 3 most common pediatric disorders causing sudden cardiac death and identifiable by ECG. Information to develop simulation model assumptions was drawn from the existing literature, Medicaid fees, and expert judgment. Sensitivity analyses examined parameter ranges to identify influential sources of uncertainty. Outcomes included costs and lost life-years caused by condition-related mortality. Our models estimate that screening for all 3 conditions simultaneously would reduce sudden death risk by 3.6 to 7.5 × 10(-5) with projected life expectancy increases of 0.8 to 1.6 days per screened individual. The incremental cost-effectiveness of screening is $91,000 to $204,000 per life-year. Sensitivity analysis showed that assumed disease prevalence, baseline mortality, and the relative risk of mortality resulting from stimulant medication use and sports participation had the greatest impact on estimated cost-effectiveness.

CONCLUSION

Results based on assumptions favoring sudden cardiac death screening indicated that its cost is high relative to its health benefits.

Sudden cardiac death and preparticipation screening: the debate continues-in support of electrocardiogram-inclusive preparticipation screening

Sudden cardiac death (SCD) is the leading cause of death in young athletes during exercise, and there is international agreement among major medical and sporting bodies that young athletes should undergo preparticipation cardiovascular screening. However, there is currently no universally accepted screening protocol, and substantial debate exists about what constitutes the ideal approach to preparticipation screening. The primary objective of preparticipation screening is the detection of intrinsic structural or electrical cardiovascular disorders that predispose an athlete to SCD. Considerable evidence exists suggesting that screening athletes with only a history and physical examination leaves most athletes with a serious underlying cardiovascular disease undetected and, thus, cannot adequately achieve the primary objective of screening. Preparticipating cardiovascular screening inclusive of an electrocardiogram (ECG) greatly enhances the ability to identify athletes at risk and is the only model shown to be cost-effective and may reduce the rate of SCD. The major obstacle to ECG screening in the United States is the lack of a physician workforce skilled in interpretation of an athlete's ECG. However, recent studies have demonstrated a capacity to distinguish physiologic ECG alterations in athletes from findings suggestive of underlying pathology that is both feasible and has a low false-positive rate. Efforts are underway to increase physician education in ECG interpretation. After 2 decades debating the proper screening strategy to identify athletes at risk, the weight of scientific evidence suggests that a screening program inclusive of ECG is the only strategy that merits promotion.

Preparticipation athletic screening including an electrocardiogram: an unproven strategy for prevention of sudden cardiac death in the athlete

One of the fundamental principles of evidence-based medicine is that clinical practice should be based on evidence derived from sufficiently robust data to ensure that the benefits, risks, and costs of an intervention are known. Although intuitively appealing, athletic screening programs with routine electrocardiograms (ECGs) followed by restriction of at-risk individuals have not been demonstrated to be effective in decreasing the inherent risk of athletic sudden death. The incremental use of a screening ECG to a history and physical examination remains debatable because of insufficient evidence to conclusively resolve the issue. Long-term outcomes with a large group of athletes undergoing screening and restriction are limited to a small number of observational trials. One supports and many do not support ECG screening with athletic restriction of at-risk athletes. Although programs and policies to decrease sudden death are laudable, they need further evaluation before being implemented on a large-scale basis. Currently, athletes are best protected by a strategy of secondary prevention with improvements in resuscitation and emergency action plans.

Sudden cardiac death in athletes: what is the role of screening?

PURPOSE OF REVIEW

To briefly review the field of sudden cardiac death (SCD) in the athlete and the impact of preparticipation screening on identification of at-risk cardiovascular disorders and mortality reduction.

RECENT FINDINGS

Competitive sports activity is associated with an increase in the risk of SCD in susceptible adolescents and young adults with clinically silent cardiovascular disorders. Screening including 12-lead electrocardiogram (ECG) has been demonstrated to allow identification of athletes affected by malignant heart muscle diseases at a presymptomatic stage and lead to substantial reduction of the risk of SCD during sports. The use of modern criteria for interpretation of the ECG in the athlete significantly improves the screening accuracy by reducing the false-positive rate (increased specificity), with the important requisite of maintaining the ability for detection of life-threatening heart diseases (preserved sensitivity). Screening including ECG has a more favourable cost-benefit ratio than that based on history and physical examination alone, with cost estimates per year of life saved below the threshold to consider a health intervention as cost-effective. Screening with exercise testing middle-aged/senior athletes engaged in leisure sports activity is likely to be cost-effective in older patients with coronary risk factors, while it is not justified in low-risk subgroups.

SUMMARY

Preparticipation screening is a life-saving and cost-effective strategy in young athletes in whom SCD is mostly caused by ECG-detectable heart muscle diseases.

Electrocardiogram screening for disorders that cause sudden cardiac death in asymptomatic children: a meta-analysis

BACKGROUND AND OBJECTIVES

Pediatric sudden cardiac death (SCD) occurs in an estimated 0.8 to 6.2 per 100 000 children annually. Screening for cardiac disorders causing SCD in asymptomatic children has public appeal because of its apparent potential to avert tragedy; however, performance of the electrocardiogram (ECG) as a screening tool is unknown. We estimated (1) phenotypic (ECG- or echocardiogram [ECHO]-based) prevalence of selected pediatric disorders associated with SCD, and (2) sensitivity, specificity, and predictive value of ECG, alone or with ECHO.

METHODS

We systematically reviewed literature on hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), and Wolff-Parkinson-White syndrome, the 3 most common disorders associated with SCD and detectable by ECG.

RESULTS

We identified and screened 6954 abstracts, yielding 396 articles, and extracted data from 30. Summary phenotypic prevalences per 100 000 asymptomatic children were 45 (95% confidence interval [CI]: 10-79) for HCM, 7 (95% CI: 0-14) for LQTS, and 136 (95% CI: 55-218) for Wolff-Parkinson-White. The areas under the receiver operating characteristic curves for ECG were 0.91 for detecting HCM and 0.92 for LQTS. The negative predictive value of detecting either HCM or LQTS by using ECG was high; however, the positive predictive value varied by different sensitivity and specificity cut-points and the true prevalence of the conditions.

CONCLUSIONS

Results provide an evidence base for evaluating pediatric screening for these disorders. ECG, alone or with ECHO, was a sensitive test for mass screening and negative predictive value was high, but positive predictive value and false-positive rates varied.

Pediatric sudden cardiac arrest

Pediatric sudden cardiac arrest (SCA), which can cause sudden cardiac death if not treated within minutes, has a profound effect on everyone: children, parents, family members, communities, and health care providers. Preventing the tragedy of pediatric SCA, defined as the abrupt and unexpected loss of heart function, remains a concern to all. The goal of this statement is to increase the knowledge of pediatricians (including primary care providers and specialists) of the incidence of pediatric SCA, the spectrum of causes of pediatric SCA, disease-specific presentations, the role of patient and family screening, the rapidly evolving role of genetic testing, and finally, important aspects of secondary SCA prevention. This statement is not intended to address sudden infant death syndrome or sudden unexplained death syndrome, nor will specific treatment of individual cardiac conditions be discussed. This statement has been endorsed by the American College of Cardiology, the American Heart Association, and the Heart Rhythm Society.

Primary prevention of sudden cardiac death of the young athlete: the controversy about the screening electrocardiogram and its innovative artificial intelligence solution

The preparticipation screening for athlete participation in sports typically entails a comprehensive medical and family history and a complete physical examination. A 12-lead electrocardiogram (ECG) can increase the likelihood of detecting cardiac diagnoses such as hypertrophic cardiomyopathy, but this diagnostic test as part of the screening process has engendered considerable controversy. The pro position is supported by argument that international screening protocols support its use, positive diagnosis has multiple benefits, history and physical examination are inadequate, primary prevention is essential, and the cost effectiveness is justified. Although the aforementioned myriad of justifications for routine ECG screening of young athletes can be persuasive, several valid contentions oppose supporting such a policy, namely, that the sudden death incidence is very (too) low, the ECG screening will be too costly, the false-positive rate is too high, resources will be allocated away from other diseases, and manpower is insufficient for its execution. Clinicians, including pediatric cardiologists, have an understandable proclivity for avoiding this prodigious national endeavor. The controversy, however, should not be focused on whether an inexpensive, noninvasive test such as an ECG should be mandated but should instead be directed at just how these tests for young athletes can be performed in the clinical imbroglio of these disease states (with variable genetic penetrance and phenotypic expression) with concomitant fiscal accountability and logistical expediency in this era of economic restraint. This monumental endeavor in any city or region requires two crucial elements well known to business scholars: implementation and execution. The eventual solution for the screening ECG dilemma requires a truly innovative and systematic approach that will liberate us from inadequate conventional solutions. Artificial intelligence, specifically the process termed "machine learning" and "neural networking," involves complex algorithms that allow computers to improve the decision-making process based on repeated input of empirical data (e.g., databases and ECGs). These elements all can be improved with a national database, evidence-based medicine, and in the near future, innovation that entails a Kurzweilian artificial intelligence infrastructure with machine learning and neural networking that will construct the ultimate clinical decision-making algorithm.

The pre-sports cardiovascular evaluation: should it depend on the level of competition, the sport, or the state?

Sudden cardiac death (SCD) in an athlete is a rare but tragic event, and significant controversy exists regarding the most effective method to define those at highest risk. Recommendations of the American Heart Association require that a history and physical examination be used for preparticipation screening with an abnormal cardiac finding expected to prompt further evaluation. Given the lack of data documenting that electrocardiogram (ECG) screening in all competitive athletes is either feasible or appropriate, these same guidelines state that such screening is optional but not mandatory. The extremely low incidence of SCD events, in conjunction with the low sensitivity and specificity of ECG as a screening tool in athletes, contributes to this recommendation. Although these guidelines target all competitive athletes, however, there may be subgroups of athletes, based on age, level of competition, individual sport, or state of residence, for which mandatory ECG screening may be both appropriate and sensible. Given the lack of resolution of the ongoing ECG debate, it is perhaps reasonable to consider screening specific high-risk subgroups of athletes rather than continuing to dispute whether to screen all competitive athletes or none at all. Recent data suggest that such a program may be feasible and may provide a rationale basis for subsequent expansion of cardiovascular screening programs.

Prevalence and spectrum diseases predisposing to sudden cardiac death: are they the same for both the athlete and the nonathlete?

Sudden cardiac death (SCD) is a rare but devastating event among young people. The precise scale of the event remains undefined. This uncommon but catastrophic event usually is proved to be the consequence of varied unsuspected congenital or acquired cardiovascular diseases. Hypertrophic cardiomyopathy and coronary artery anomalies are the two most frequent causes of SCD. Most commonly, SCD resulting from these diseases occurs during or immediately after exercise. This report highlights the prevalence and spectrum of SCD-predisposing diseases and how they are affected by athletic participation. In addition, disease-specific guidelines for sports participation are addressed.

Prevalence of electrocardiographic abnormalities in an unselected young male multi-ethnic South-East Asian population undergoing pre-participation cardiovascular screening: results of the Singapore Armed Forces Electrocardiogram and Echocardiogram screening protocol

AIMS

Resting 12-lead electrocardiograms (ECGs) have been employed in the pre-participation evaluation of young asymptomatic subjects to detect pre-existing heart diseases. Although the incorporation of routine ECG in pre-participation screening remains controversial, there is increasing evidence that cardiomyopathies and ion channelopathies have ECG changes as the initial manifestation. The causes of sudden cardiac death in young people show significant geographical variation. We aim to determine the prevalence and spectrum of ECG abnormalities in a young male South-East Asian population.

METHODS AND RESULTS

The Singapore Armed Forces Electrocardiogram and Echocardiogram (SAFE) protocol is an ECG-based pre-participation cardiac screening programme modelled after the Italian system. From October 2008 to May 2009, a total of 18 476 young male conscripts (mean age 19.5 years old, range 16-27) underwent mandatory pre-enlistment medical screening at a single medical facility. Subjects with abnormal ECG findings were classified into two groups: Group A had ECG changes that fulfilled a pre-specified checklist to screen for hypertrophic cardiomyopathy and were referred for transthoracic echocardiogram; Group B had other ECG abnormalities [such as Brugada pattern, Wolff-Parkinson-White (WPW) pattern, long QTc] and were referred for secondary screening at a tertiary institution. Of the 18 476 subjects screened, 7.0% (n= 1285) had ECG abnormalities. Of note, 19 (0.10%) had Brugada pattern, 25 (0.14%) had WPW pattern, and 31 (0.17%) had prolonged QT interval on ECG. The prevalence of ECG abnormalities was significantly higher in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003).

CONCLUSION

The prevalence of ECG abnormalities in a young, South-East Asian male population was 7.0%. There were significant ethnic differences, with ECG abnormalities more prevalent in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003). The inclusion of universal ECG, in addition to history and physical examination, may increase the sensitivity of a cardiovascular screening programme. Knowledge of the spectrum and prevalence of ECG abnormalities and disease conditions would be pivotal in designing customized screening programmes.

Cardiovascular considerations of attention deficit hyperactivity disorder medications: a report of the European Network on Hyperactivity Disorders work group, European Attention Deficit Hyperactivity Disorder Guidelines Group on attention deficit hyperactivity disorder drug safety meeting

Regulatory decisions regarding attention deficit hyperactivity disorder drug licensing and labelling, along with recent statements from professional associations, raise questions of practice regarding the evaluation and treatment of patients with attention deficit hyperactivity disorder. To address these issues for the European community, the European Network for Hyperkinetic Disorders, through its European Attention Deficit Hyperactivity Disorder Guidelines Group, organised a meeting between attention deficit hyperactivity disorder specialists, paediatric cardiovascular specialists, and representatives of the major market authorisation holders for attention deficit hyperactivity disorder medications. This manuscript represents their consensus on cardiovascular aspects of attention deficit hyperactivity disorder medications. Although sudden death has been identified in multiple young individuals on attention deficit hyperactivity disorder medication causing regulatory concern, when analysed for exposure using currently available data, sudden death does not appear to exceed that of the general population. There is no current evidence to suggest an incremental benefit to electrocardiography assessment of the general attention deficit hyperactivity disorder patient. Congenital heart disease patients have an increased prevalence of attention deficit hyperactivity disorder, and can benefit from attention deficit hyperactivity disorder therapies, including medication. The attention deficit hyperactivity disorder specialist is the appropriate individual to evaluate benefit and risk and recommend therapy in all patients, although discussion with a heart specialist is reasonable for congenital heart disease patients. For attention deficit hyperactivity disorder patients with suspected heart disease or risk factor/s for sudden death, assessment by a heart specialist is recommended, as would also be the case for a non-attention deficit hyperactivity disorder patient. The identification of risk factors for sudden death should not automatically exclude the use of attention deficit hyperactivity disorder medication.

Prevalence of Cardiomyopathy in Italian Asymptomatic Children With Electrocardiographic T-Wave Inversion at Preparticipation Screening

Background—

T-wave inversion on a 12-lead ECG is usually dismissed in young people as normal persistence of the juvenile pattern of repolarization. However, T-wave inversion is a common ECG abnormality of cardiomyopathies such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy, which are leading causes of sudden cardiac death in athletes. We prospectively assessed the prevalence, age relation, and underlying cardiomyopathy of T-wave inversion in children undergoing preparticipation screening.

Methods and Results—

The study population included 2765 consecutive Italian children (1914 male participants; mean age, 13.9±2.2 years; range 8–18 years) undergoing preparticipation screening including an ECG. Of 229 children (8%) who underwent further evaluation because of positive findings at initial preparticipation screening, 33 (1.2%) were diagnosed with cardiovascular disease. T-wave inversion was recorded in 158 children (5.7%) and was localized in the right precordial leads in 131 (4.7%). The prevalence of right precordial T-wave inversion decreased significantly with increasing age (8.4% in children <14 years of age versus 1.7% in those ≥14 years; P <0.001), pubertal development (9.5% of children with incomplete versus 1.6% with complete development; P <0.001), and body mass index below the 10th percentile ( P <0.001). Incomplete pubertal development was the only independent predictor for right precordial T-wave inversion (odds ratio, 3.6; 95% confidence interval, 1.9–6.8; P <0.001). Of 158 children with T-wave inversion, 4 (2.5%) had a diagnosis of cardiomyopathy, including arrhythmogenic right ventricular cardiomyopathy (n=3) and hypertrophic cardiomyopathy (n=1).

Conclusions—

The prevalence of T-wave inversion decreases significantly after puberty. Echocardiographic investigation of children with postpubertal persistence of T-wave inversion at preparticipation screening is warranted because it may lead to presymptomatic diagnosis of a cardiomyopathy that could lead to sudden cardiac death during sports.

Association of heart rate variability with arrhythmic events in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is associated with an increased risk of sudden cardiac death (SCD). Risk stratification of ARVC/D patients, however, remains an unresolved issue. In this study we investigated whether heart rate variability (HRV) can be helpful in identifying ARVC/D patients with increased risk of arrhythmic events.

METHODS AND RESULTS

We studied 30 consecutive patients (17 males; 45.4 ± 18 years) with ARVC/D, diagnosed according to guideline criteria; 15 patients (50%) had received an implantable cardioverter defibrillator (ICD) for primary SCD prevention. HRV was assessed on 24-h ECG Holter monitoring. The primary endpoint was the occurrence of major arrhythmic events (SCD, sustained ventricular tachycardia (VT), ICD therapy for sustained VT or ventricular fibrillation (VF)). During the follow-up period (19 ± 7 months), no deaths occurred, but 5 patients (17%) experienced arrhythmic events (4 VTs and 1 VF, all in the ICD group). All HRV parameters were significantly lower in patients with, compared with those without, arrhythmic events. Low-frequency amplitude was the most significant HRV variable associated with arrhythmic events in univariate Cox regression analysis (P=0.017), and was the only significant predictor of arrhythmic events in multivariable regression analysis (hazard ratio 0.88, P=0.047), together with unexplained syncope (hazard ratio 16.1, P=0.039).

CONCLUSIONS

Our data show that among ARVC/D patients HRV analysis might be helpful in identifying those with increased risk of major arrhythmic events.

Long-term outcomes in hypertrophic cardiomyopathy caused by mutations in the cardiac troponin T gene

BACKGROUND

Hypertrophic cardiomyopathy caused by mutations in the cardiac troponin T gene (TNNT2) has been associated with a high risk of sudden cardiac death (SCD) and mild left ventricular hypertrophy. However, previous studies are limited by sample size, cross-sectional design, and few data in relatives.

METHODS AND RESULTS

Five hundred fifty-two unrelated hypertrophic cardiomyopathy probands were screened for TNNT2 mutations. First-degree relatives were invited for clinical and genetic evaluation. Ninety-two individuals (20 probands and 72 relatives) carried TNNT2 mutations (51 [55%] male; 30±17 years). ECGs and echo were available in 87 (95%) and 88 (96%) individuals, respectively. ECG was normal in 13 (68%) children (<16 years) and 13 (19%) adults. Echo was normal in 18 (90%) children and 16 (24%) adults; 7 (10%) adults had a normal ECG and echo. Thirteen (65%) of 20 families had a history of SCD. Follow-up was available for 75 patients (mean, 9.9±5.2 years); 2 of 16 adults and 2 of 18 children with normal echoes developed left ventricular hypertrophy. Twenty-three (22%) received an implantable cardioverter-defibrillator (20 for primary prophylaxis). One child and 3 adults died of SCD and 2 adults were resuscitated from ventricular fibrillation. One patient had an appropriate implantable cardioverter-defibrillator discharge. The rate of cardiovascular death, transplant, and implantable cardioverter-defibrillator discharge was 1.6% (0.016 person/y; 95% confidence interval, 0.83-2.79%), and SCD 0.93% (0.0093 person/y; 95% confidence interval, 0.37-1.92%).

CONCLUSIONS

Left ventricular hypertrophy is rare in children with TNNT2 mutations. Left ventricular hypertrophy is absent in the minority of adults, but most have an abnormal ECG. Despite adverse family histories, the rate of cardiovascular death during follow-up was similar to that reported in large referral populations.

Hypertrophic cardiomyopathy and ultra-endurance running - two incompatible entities?

Regular and prolonged exercise is associated with increased left ventricular wall thickness that can overlap with hypertrophic cardiomyopathy (HCM). Differentiating physiological from pathological hypertrophy has important implications, since HCM is the commonest cause of exercise-related sudden cardiac death in young individuals. Most deaths have been reported in intermittent 'start-stop' sports such as football (soccer) and basketball. The theory is that individuals with HCM are unable to augment stroke volume sufficiently to meet the demands of endurance sports and are accordingly 'selected-out' of participation in such events. We report the case of an ultra-endurance athlete with 25 years of > 50 km competitive running experience, with genetically confirmed HCM; thereby demonstrating that these can be two compatible entities.

Pathophysiology of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (AC) is a clinically and genetically heterogeneous disorder of heart muscle that is associated with ventricular arrhythmias and risk of sudden cardiac death, particularly in the young and athletes. Mutations in five genes that encode major components of the desmosomes, namely junction plakoglobin, desmoplakin, plakophilin-2, desmoglein-2, and desmocollin-2, have been identified in approximately half of affected probands. AC is, therefore, commonly considered a 'desmosomal' disease. No single test is sufficiently specific to establish a diagnosis of AC. The diagnostic criteria for AC were revised in 2010 to improve sensitivity, but maintain specificity. Quantitative parameters were introduced and identification of a pathogenic mutation in a first-degree relative has become a major diagnostic criterion. Caution in the interpretation of screening results is highly recommended because a 'pathogenic' mutation is difficult to define. Experimental data confirm that this genetically determined cardiomyopathy develops after birth because of progressive myocardial dystrophy, and is initiated by cardiomyocyte necrosis; cellular and animal models are necessary to gain insight into the cascade of underlying molecular events. Crosstalk from the desmosome to the nucleus, gap junctions, and ion channels is under investigation, to move from symptomatic to targeted therapy, with the ultimate aim to stop disease onset and progression.