Electrocardiographic changes in 1000 highly trained junior elite athletes

Comparison of frequency of significant electrocardiographic abnormalities in endurance versus nonendurance athletes

Most data assessing the accuracy of electrocardiographic (ECG) screening in identifying cardiac pathology in athletes are derived from relatively unselected cohorts of subjects involved in competitive sports. We hypothesized that the prevalence of ECG abnormalities may be greater in athletes performing the greatest combination of exercise intensity and duration, namely professional endurance athletes. A total of 1,007 male and 254 female elite adult athletes underwent cardiovascular screening inclusive of an electrocardiogram, interpreted using the 2010 European Society of Cardiology guidelines. Training-related ECG changes (group 1) were more common in endurance athletes (EAs) than nonendurance athletes (NEAs; 90.8% vs 86.0%, p = 0.04), as were multiple (≥2) training-related changes (78.9% vs 53.5%, p <0.0001). Group 2 ECG changes (previously considered uncommon and training unrelated) were seen in 18.1% of subjects and were twice as prevalent in EAs compared with NEAs (29.9% vs 15.1%, p <0.0001). Right ventricular hypertrophy (4.4% EAs vs 1.5% NEAs, p <0.005) and deep right precordial T-wave inversion (14.3% EAs vs 4.7% NEAs, p <0.0001) were 3 times as common in EAs. Both group 1 and group 2 changes were similarly prevalent among elite male and female athletes and were more common in EAs regardless of gender. In conclusion, ECG abnormalities are very common in elite athletes and are more common in EAs than NEAs. Right ventricular hypertrophy and deep right precordial T-wave inversion are particularly common in EAs, possibly because of increased structural and/or electrical right ventricular remodeling in this subgroup. The predictive value of ECG screening and criteria for abnormal findings in elite EAs requires specific appraisal.

Impact of ethnicity on cardiac adaptation to exercise

The increasing globalization of sport has resulted in athletes from a wide range of ethnicities emerging onto the world stage. Fuelled by the untimely death of a number of young professional athletes, data generated from the parallel increase in preparticipation cardiovascular evaluation has indicated that ethnicity has a substantial influence on cardiac adaptation to exercise. From this perspective, the group most intensively studied comprises athletes of African or Afro-Caribbean ethnicity (black athletes), an ever-increasing number of whom are competing at the highest levels of sport and who often exhibit profound electrical and structural cardiac changes in response to exercise. Data on other ethnic cohorts are emerging, but remain incomplete. This Review describes our current knowledge on the impact of ethnicity on cardiac adaptation to exercise, starting with white athletes in whom the physiological electrical and structural changes--collectively termed the 'athlete's heart'--were first described. Discussion of the differences in the cardiac changes between ethnicities, with a focus on black athletes, and of the challenges that these variations can produce for the evaluating physician is also provided. The impact of ethnically mediated changes on preparticipation cardiovascular evaluation is highlighted, particularly with respect to false positive results, and potential genetic mechanisms underlying racial differences in cardiac adaptation to exercise are described.

Sports participation during teenage years

Ensuring the safety of young athletes is a priority among health care providers. Controversy remains as to the best method of preparticipation screening. The American Academy of Pediatrics and the American Heart Association currently recommend screening with history and physical examination, without routine electrocardiogram or echocardiography. Meticulous conduction of a cardiac focused history and exam during the preparticipation evaluation can help identify those who may be at risk for sudden cardiac arrest. Understanding presenting signs of the most common cardiac diseases is useful in recognizing those in need of a directed cardiac evaluation before sports participation.

The asymptomatic teenager with an abnormal electrocardiogram

Use of medications for attention-deficit hyperkinetic disorder and preparticipation sports physical examination has led to an increase in number of electrocardiograms (ECG) performed during adolescence. Interpreting ECGs in children and young adults must take into account the evolutionary changes with age and the benign variants, which are usually not associated with heart disease. It is crucial for primary-care providers to recognize the changes on ECG associated with heart disease and risk of sudden death. In this article, the significance, sensitivity, specificity, and the diagnostic workup of these findings in the asymptomatic teenager are discussed.

Clinical significance of electrocardiographic right ventricular hypertrophy in athletes: comparison with arrhythmogenic right ventricular cardiomyopathy and pulmonary hypertension

AIMS

Pre-participation cardiovascular screening of young athletes may prevent sports-related sudden cardiac deaths. Recognition of physiological electrocardiography (ECG) changes in healthy athletes has improved the specificity of screening while maintaining sensitivity for disease. The study objective was to determine the clinical significance of electrocardiographic right ventricular hypertrophy (RVH) in athletes.

METHODS AND RESULTS

Between 2010 and 2012, 868 subjects aged 14-35 years (68.8% male) were assessed using ECG and echocardiography (athletes; n = 627, sedentary controls; n = 241). Results were compared against patients with established right ventricular (RV) pathology (arrhythmogenic right ventricular cardiomyopathy, n = 68; pulmonary hypertension, n = 30). Sokolow-Lyon RVH (R[V1]+S[V5orV6] > 1.05 mV) was more prevalent in athletes than controls (11.8 vs. 6.2%, P = 0.017), although RV wall thickness (RVWT) was similar (4.0 ± 1.0 vs. 3.9 ± 0.9 mm, P = 0.18). Athletes exhibiting electrocardiographic RVH were predominantly male (95.9%), and demonstrated similar RV dimensions and function to athletes with normal electrocardiograms (RVWT; 4.0 ± 1.1 vs. 4.0 ± 0.9 mm, P = 0.95, RV basal dimension; 42.7 ± 5.2 vs. 42.1 ± 5.9 mm, P = 0.43, RV fractional area change; 40.6 ± 7.6 vs. 42.2 ± 8.1%, P = 0.14). Sensitivity and specificity of Sokolow-Lyon RVH for echocardiographic RVH (>5 mm) were 14.3 and 88.2%, respectively. Further evaluation including cardiac magnetic resonance imaging did not diagnose right ventricular pathology in any athlete. None of the cardiomyopathic or pulmonary hypertensive patients exhibited voltage RVH without additional ECG abnormalities.

CONCLUSION

Electrocardiographic voltage criteria for RVH are frequently fulfilled in healthy athletes without underlying RV pathology, and should not prompt further evaluation if observed in isolation. Recognition of this phenomenon should reduce the burden of investigations after pre-participation ECG screening without compromising sensitivity for disease.

Should axis deviation or atrial enlargement be categorised as abnormal in young athletes? The athlete's electrocardiogram: time for re-appraisal of markers of pathology

AIMS

The 2010 European Society of Cardiology (ESC) guidelines for electrocardiogram (ECG) interpretation in athletes are associated with a relatively high false positive rate and warrant modification to improve the specificity without compromising sensitivity. The aim of this study was to investigate whether non-specific anomalies such as axis deviation and atrial enlargement in isolation require further assessment in highly trained young athletes.

METHOD AND RESULTS

Between 2003 and 2011, 2533 athletes aged 14-35 years were investigated with 12-lead ECG and echocardiography. Electrocardiograms were analysed for non-training-related (Group 2) changes according to the 2010 ESC guidelines. Results were compared with 9997 asymptomatic controls. Of the 2533 athletes, 329 (13%) showed Group 2 ECG changes. Isolated axis deviation and isolated atrial enlargement comprised 42.6% of all Group 2 changes. Athletes revealed a slightly higher prevalence of these anomalies compared with controls (5.5 vs. 4.4%; P = 0.023). Echocardiographic evaluation of athletes and controls with isolated axis deviation or atrial enlargement (n = 579) failed to identify any major structural or functional abnormalities. Exclusion of axis deviation or atrial enlargement reduced the false positive rate from 13 to 7.5% and improved specificity from 90 to 94% with a minimal reduction in sensitivity (91-89.5%).

CONCLUSION

Isolated axis deviation and atrial enlargement comprise a high burden of Group 2 changes in athletes and do not predict underlying structural cardiac disease. Exclusion of these anomalies from current ESC guidelines would improve specificity and cost-effectiveness of pre-participation screening with ECG.

Cardiac adaptation to exercise in adolescent athletes of African ethnicity: an emergent elite athletic population

BACKGROUND/AIMS

Adult black athletes (BA) exhibit left ventricular hypertrophy (LVH) on echocardiography and marked ECG repolarisation changes resembling those observed in hypertrophic cardiomyopathy (HCM). Limited data are available for adolescent BA, the group most vulnerable to exercise-related sudden cardiac death.

METHODS

Between 1996 and 2011, 245 male and 84 female adolescent BA from a wide variety of sporting disciplines underwent cardiac evaluation including ECG and echocardiography. Athletes exhibiting T-wave inversions and/or echocardiographic LVH were investigated further for quiescent cardiomyopathies. Results were compared with 903 adolescent white athletes (WA) and 134 adolescent sedentary black controls (BC).

RESULTS

LVH on echocardiography was present in 7% of BA compared to only 0.6% of WA and none of the BC. In the very young (<16 years), 5.5% of BA, but none of the WA, demonstrated LVH. Within the BA group, LVH was more prevalent in men compared to women (9% vs 1.2%, p=0.012). T-wave inversions were present in 22.8% BA, 4.5% WA and 13.4% BC. T-wave inversions in BA occurred with similar frequency in men and women and were predominantly confined to leads V1-V4. T-wave inversions in the lateral leads, commonly associated with cardiomyopathies, were present in 2.4% of BA. On a further evaluation and mean follow-up of 8.3 years, none of the athletes exhibited HCM.

CONCLUSIONS

Athletic training has a pronounced effect on adolescent BA. Black athletes as young as 14 years of age may exhibit left ventricular wall thicknesses of 15 mm and marked repolarisation changes resembling HCM. Male and female BA demonstrate a high prevalence of T-wave inversions.

Significance of deep T-wave inversions in asymptomatic athletes with normal cardiovascular examinations: practical solutions for managing the diagnostic conundrum

Preparticipation screening programmes for underlying cardiac pathologies are now commonplace for many international sporting organisations. However, providing medical clearance for an asymptomatic athlete without a family history of sudden cardiac death (SCD) is especially challenging when the athlete demonstrates particularly abnormal repolarisation patterns, highly suggestive of an inherited cardiomyopathy or channelopathy. Deep T-wave inversions of ≥ 2 contiguous anterior or lateral leads (but not aVR, and III) are of major concern for sports cardiologists who advise referring team physicians, as these ECG alterations are a recognised manifestation of hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Subsequently, inverted T-waves may represent the first and only sign of an inherited heart muscle disease, in the absence of any other features and before structural changes in the heart can be detected. However, to date, there remains little evidence that deep T-wave inversions are always pathognomonic of either a cardiomyopathy or an ion channel disorder in an asymptomatic athlete following long-term follow-up. This paper aims to provide a systematic review of the prevalence of T-wave inversion in athletes and examine T-wave inversion and its relationship to structural heart disease, notably HCM and ARVC with a view to identify young athletes at risk of SCD during sport. Finally, the review proposes clinical management pathways (including genetic testing) for asymptomatic athletes demonstrating significant T-wave inversion with structurally normal hearts.

Differentiating athlete's heart from inherited cardiac pathology: the challenge of repolarisation abnormalities presenting during anaesthesia

This case report describes an asymptomatic healthy male professional athlete who underwent general anaesthesia for a routine orthopaedic operation. Peri-procedure, pronounced ST elevation suggestive of myocardial ischaemia manifested on the electrocardiogram lasting for four hours post-procedure, upon which the athlete developed deep and diffuse inferolateral T-wave inversion. These changes resolved spontaneously and the patient remained clinically stable throughout. This case demonstrates the clinical conundrum facing anaesthetists attempting to differentiate between repolarisation anomalies that are commonly observed in high-level athletes and those of inherited cardiac pathology, namely hypertrophic cardiomyopathy, which is the leading cause of sudden cardiac death in young athletes.

Soccer and Sudden Cardiac Death in Young Competitive Athletes: A Review

Sudden cardiac death (SCD) in young competitive athletes (<35 years old) is a tragic event that has been brought to public attention in the past few decades. The incidence of SCD is reported to be 1-2/100,000 per year, with athletes at a 2.5 times higher risk. Soccer is the most popular sport in the world, played by people of all ages. However, unfortunately it is cardiovascular diseases such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy that have subtly missed screening and claimed the lives of soccer stars such as Marc Vivien Foe and Antonio Puerta during live action on the field and on an internationally televised stage. This paper covers the physiological demands of soccer and the relationship between soccer and SCD. It also reviews the most common causes of SCD in young athletes, discusses the current guidelines in place by The Fédération Internationale de Football Association (FIFA) for screening among professional soccer players, and the precautions that have been put in place to prevent SCD on the field in professional soccer.

[Athlete's heart in the young: electrocardiographic and echocardiographic patterns in 107 French athletes]

PURPOSE

Since 2009 in France, every people practicing sport in competition must have a cardiovascular exam with electrocardiogram, to prevent sudden cardiac death. Sometimes, an echocardiography will be necessary. Little is known about athlete's heart in the young, particularly in the French people.

PATIENTS AND METHODS

One hundred and seven French elite adolescent athletes had an electrocardiogram with echocardiography to establish reference values in this population.

RESULTS

QTcorrected (QTc) interval calculated by the Hodges formula, is always in the normal values. Interventricular septal thickness is always ≤ 11 mm and left ventricular end diastolic diameter ≤ 55 mm in about 90 % of the athletes. Females have QTc interval longer than males and interventricular septal thickness finer. Diastolic function (18.9 ± 2.6 cm/s for e', E/e' ratio at 5.3 ± 0.8) is "supernormal" and correlate with age and cardiac frequency. Right ventricular systolic function is always good.

CONCLUSION

Adolescent athlete's heart is normal. If QTc interval is not normal, be afraid of a QT long syndrome. Furthermore, when interventricular septal thickness is > 11 mm or left ventricular end diastolic diameter > 55 mm, myocardiopathy will have to be ruled out.

Normal electrocardiographic QT interval in race-fit Standardbred horses at rest and its rate dependence during exercise

OBJECTIVES

Cardiac repolarization, measured as QT and Tpeak to Tend (TpTe) intervals on the ECG, is important, as irregularities caused by diseases, ventricular hypertrophy, drugs and genetic defects can trigger arrhythmias which predispose human patients to syncope and sudden cardiac death. In horses, repolarization is not well described and therefore QT analysis cannot yet be used diagnostically. Therefore, we sought to describe reference values for the normal QT and TpTe intervals in Standardbreds and to determine the best method for heart rate (HR) correction.

ANIMALS

30 Standardbreds.

METHODS

QT and TpTe intervals were measured during rest and exercise and plotted against HR converted to Rpeak to Rpeak interval (RR). Data were fitted with relevant regression models. Intra- and inter-observer agreement was assessed using Bland-Altman analyses.

RESULTS

Data were best described by a piecewise linear model (r(2) > 0.97). Average prediction error of this model was smaller than for both Bazett and Fridericia corrections. Coefficient of repeatability of intra- and inter-observer variability was 8.76 ms and 5.64 ms respectively and coefficient of variation was 1.77% and 2.76% respectively. TpTe increased with RR in stallions.

CONCLUSIONS

The QT interval in Standardbred horses shortens with decreasing RR interval (increasing HR) as in humans, but in a markedly different order as it clearly follows a piecewise linear model. The equine QT interval can be measured easily and there is small intra- and inter-observer variability. This model of the equine QT interval provides clinicians with a method that could support a diagnosis of repolarization disturbances in horses.

Arrhythmias in athletes: evidence-based strategies and challenges for diagnosis, management, and sports eligibility

Assessment and management of cardiac rhythm disorders in athletes is particularly challenging. An accurate diagnosis and optimal risk-stratification are often limited because of substantial phenotypic overlap between pathological entities and adaptive cardiovascular responses that normally occur in athletes. An accurate diagnosis, however, is particularly important in this population, as 2 competing risks need to be cautiously balanced: the risk of under-diagnosis of an arrhythmogenic substrate that may trigger life-threatening events versus the risk of over-diagnosis that may result in an athlete's improper disqualification. Accordingly, the management of arrhythmias in athletes may pose therapeutic dilemmas, and often differs substantially compared with the general population. In this review, we present the most frequently observed arrhythmias in athletes and briefly discuss their pathophysiologic substrate. We further propose diagnostic and therapeutic strategies based upon current guidelines, official recommendations, and emerging evidence from relevant clinical investigations. We focus particularly on disparities in current guidelines regarding the management of certain rhythm disorders, as these areas of uncertainty may reflect the challenging nature of these disorders and may indicate the need for individualized approaches in every-day clinical practice. A better understanding of the normal electrophysiological responses to chronic exercise, and of the pathophysiological basis and the true clinical significance of arrhythmias in athletes, may enhance decision-making, and may allow for management strategies which more prudently weigh the risk-to-benefit ratio of each approach.

[ECG diagnostics in competitive athletes. Current implications for preparticipation screening]

In young competitive athletes sudden cardiac death frequently occurs as a tragic first manifestation of clinically inapparent underlying structural or electrical cardiac disorders. An increased risk may be reflected by typical electrocardiogram (ECG) alterations preceding symptoms but a correct interpretation is often challenging due to a high prevalence of training-related ECG alterations in competitive athletes mimicking such disorders. Misinterpretation may thus result in either unnecessary disqualification from competitive sports or continuation despite an increased risk or extensive diagnostic work-ups yielding additional equivocal findings. However, as observed in large athlete cohorts in recent years a variety of ECG alterations, such as isolated increased QRS voltage, early repolarization, sinus bradycardia, first degree AV block or incomplete right bundle branch block, represent common variants of ECGs of athletes reflecting physiological and training-related cardiac adaptations. These alterations do not usually require further diagnostic evaluation. In contrast, alterations such as repolarization abnormalities, complete bundle branch block, prolonged QT intervals or pathological Q waves, are strongly suggestive of underlying disorders and require further evaluation even in asymptomatic athletes. Thus, the ECG plays a pivotal role in the prevention of sudden cardiac death in competitive athletes. The present article summarizes current recommendations for the interpretation of athlete ECGs regarding the differentiation between physiological or pathological cardiac adaptation.

T-wave inversions and the role of de-training in the differentiation of athlete's heart from pathology: is 6 months too long?

Electrocardiographic changes are common in athletes. Differentiation of a physiological from a pathological substrate is important as ECG changes may indicate underlying cardiac disease placing the athlete at increased risk of sudden cardiac death. Deep T-wave inversions are uncommon in Caucasian athletes however; appear more prevalent in black athletes. Irrespective of the ethnic origin of the athlete, deep T-wave inversions require thorough follow-up. At present, 6 months de-training is recommended to assist in the differentiation of physiologic and pathologic changes where a definitive diagnosis is elusive through standard diagnostic techniques. This case study examines findings from a black and a Caucasian athlete presenting with deep T-wave inversions following a brief (ca.3 week) period of de-training resulting in normalisation of T-wave. These cases suggest that a shorter period of time may be sufficient in differentiating physiological from pathological mechanisms for deep T-wave inversions.

Detraining-related changes in left ventricular wall thickness and longitudinal strain in a young athlete likely to have hypertrophic cardiomyopathy

One of the diagnostic criteria in order to differentiate between physiological and pathological left ventricular hypertrophy is the wall thickness reduction after at least 3-month detraining period, which is considered a marker of the athlete's heart. This report describes detraining-related regression of LV hypertrophy and improvement in myocardial deformation in a junior athlete likely to have hypertrophic cardiomyopathy. Key pointsHypertrophic cardiomyopathy in adolescent athletes can be discovered by 12-lead ECGPhysical training is an important trigger for the clinical presentation of hypertrophic cardiomyopathyReverse LV remodeling (wall thickness reduction) with detraining is a common echocardiographic finding in athletes with physiological hypertrophyThis report demonstrates that reverse remodeling can also be found in adolescent athletes likely to have hypertrophic cardiomyopathy.

Comparison of usefulness of Sokolow and Cornell criteria for left ventricular hypertrophy in subjects aged <20 years versus >30 years

The use of electrocardiography in sports or military screening is considered an effective tool for diagnosing potentially fatal conditions. The present study was designed to compare the yield of electrocardiographic criteria for left ventricular hypertrophy (LVH) criteria for the diagnosis of LVH and hypertrophic obstructive cardiomyopathy in subjects aged <20 years and >30 years. The association between the electrocardiographic (ECG) criteria for LVH (ECG-LVH) and echocardiographic findings was compared in 4 groups of air force academy candidates: (1) young candidates undergoing echocardiography because of ECG-LVH findings (n = 666); (2) young candidates without ECG-LVH findings undergoing routine echocardiography (n = 4,043); (3) older designated aviators undergoing echocardiography because of ECG-LVH findings (n = 196); and (4) older designated aviators undergoing routine echocardiography without ECG-LVH findings (n = 1,098). The predictive value of ECG-LVH findings for echocardiographic LVH, left ventricular mass, posterior wall thickness, and interventricular septal thickness were compared among the 4 groups. The ECG criteria in young subjects correlated with the left ventricular mass and posterior wall thickness but not with the interventricular septal thickness. In older subjects, these criteria correlated with left ventricular mass, interventricular septal, and posterior wall thickness. The positive and negative predictive value of ECG-LVH findings for the echocardiographic diagnosis of LVH in young subjects was 6.0% and 99.0%, respectively. In older subjects the positive and negative predictive value of ECG-LVH findings was 34% and 93%, respectively. In conclusion, ECG criteria are probably a useful tool for exclusion of LVH in young and older subjects; however, their low positive predictive value would probably lead to unnecessary echocardiographic tests, particularly in young subjects.

Assessment of electrocardiography, echocardiography, and heart rate variability in dynamic and static type athletes

Background:

Over the last two decades, morphological cardiac changes induced by athletic conditioning have been of great interest. Therefore, several studies have been orchestrated to delineate electrocardiography (ECG), echocardiography, and heart rate variability (HRV) findings in athletes.

Purpose:

To assess the ECG, echocardiography, and HRV in a group of dynamic and static type athletes.

Methods:

Fifty professional athletes (20 static and 30 dynamic exercise athletes) and 50 healthy nonathletes (control group) were recruited. Standard 12-lead ECG and transthoracic echocardiography was performed on all athletes and the control group. Through echocardiography, variables including left ventricular (LV) end-diastolic/systolic diameter, LV mass, and left atrial volume index were measured. In addition, both the athletes and the control group underwent ECG Holter monitoring for 15 minutes and several parameters related to HRV (time and frequency domain) were recorded.

Results:

The most common ECG abnormalities among the athletes were sinus bradycardia and incomplete right bundle branch block. LV end-diastolic diameter and left atrial volume index were significantly greater in the dynamic athletes (P < 0.001). LV end-systolic diameter was significantly lower in the static group (P < 0.001). LV mass of the dynamic and static athletes was significantly greater than that of the controls (P < 0.001). Among the ECG Holter monitoring findings, the dynamic athletes had lower systolic blood pressure than the controls (P = 0.01). Heart rate was lowest in the control group (P < 0.001).

Conclusion:

The most common ECG abnormalities among adolescent Iranian athletes were sinus bradycardia and incomplete right bundle branch block. Static exercise seemed to reduce LV end-systolic diameter, while dynamic exercise resulted in increased LV end-diastolic diameter and left atrial volume index. Additionally, Iranian athletes showed no differences in HRV parameters, excluding heart rate and systolic blood pressure, compared with the nonathletes.

Electrocardiogram interpretation in the athlete

The sudden death of a young athlete is a devastating event that impacts the lay public and medical community and has attracted efforts to screen for underlying cardiovascular diseases associated with sudden death in this population. Electrocardiography (ECG) screening has been shown to increase the sensitivity of finding structural heart diseases in competitive athletes. Recent research in diverse populations of athletes has led to refinements in ECG-interpretation standards designed to improve its diagnostic accuracy. This review summarizes relevant information regarding cardiovascular screening and ECG interpretation in athletes.

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.

Overview of sudden cardiac death in young athletes

Sudden cardiac death is the leading cause of nontraumatic mortality in young athletes. The estimated incidence varies; however, recent studies have provided more accurate data. Most cases are attributed to silent hereditary or congenital cardiac disorders, many of which may be detected through preparticipation screening programs. This article provides a comprehensive review of the incidence and etiology of sudden cardiac death in young athletes, with practical advice regarding evaluation and management in light of a large number of recent advances. A brief outline of current perspectives on preparticipation screening programs and prevention is included.

Is the 'athlete's heart' arrhythmogenic? Implications for sudden cardiac death

Whether the ventricular hypertrophic response to athletic training can predispose to fatal ventricular dysrhythmias via mechanisms similar to that of pathological hypertrophy is controversial. This review examines current information regarding the metabolic and electrophysiological differences between the myocardial hypertrophy of heart disease and that associated with athletic training. In animal studies, the biochemical and metabolic profile of physiological hypertrophy from exercise training can largely be differentiated from that of pathological hypertrophy, but it is not clear if the former might represent an early stage in the spectrum of the latter. Information as to whether the electrical remodelling of the athlete's heart mimics that of patients with heart disease, and therefore serves as a substrate for ventricular dysrhythmias, is conflicting. If ventricular remodelling associated with athletic training can trigger fatal dysrhythmias, such cases are extraordinarily rare and thereby impossible to investigate by any standard experimental approach. Greater insight into this issue may come from a better understanding of the electrical responses to both acute bouts of exercise and chronic training in young athletes.

Sudden cardiac death in young athletes

Athletic activity is associated with an increased risk of sudden death for individuals with some congenital or acquired heart disorders. This review considers in particular the causes of death affecting athletes below 35 years of age. In this age group the largest proportion of deaths are caused by diseases with autosomal dominant inheritance such as hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, long QT-syndrome, and Marfan's syndrome. A policy of early cascade-screening of all first-degree relatives of patients with these disorders will therefore detect a substantial number of individuals at risk. A strictly regulated system with preparticipation screening of all athletes following a protocol pioneered in Italy, including school-age children, can also detect cases caused by sporadic new mutations and has been shown to reduce excess mortality among athletes substantially. Recommendations for screening procedure are reviewed. It is concluded that ECG screening ought to be part of preparticipation screening, but using criteria that do not cause too many false positives among athletes. One such suggested protocol will show positive in approximately 5% of screened individuals, among whom many will be screened for these diseases. On this point further research is needed to define what kind of false-positive and false-negative rate these new criteria result in. A less formal system based on cascade-screening of relatives, education of coaches about suspicious symptoms, and preparticipation questionnaires used by athletic clubs, has been associated over time with a sizeable reduction in sudden cardiac deaths among Swedish athletes, and thus appears to be worth implementing even for junior athletes not recommended for formal preparticipation screening. It is strongly argued that in families with autosomal dominant disorders the first screening of children should be carried out no later than 6 to 7 years of age.

Evidence-based risk assessment and recommendations for exercise testing and physical activity clearance in apparently healthy individuals1This paper is one of a selection of papers published in this Special Issue, entitled Evidence-based risk assessment and recommendations for physical activity clearance, and has undergone the Journal’s usual peer review process

Increased physical activity (PA) is associated with improved health and quality of life in the general population. A dose–response effect is evident between increasing levels of PA participation and a lower relative risk for cardiovascular disease and all-cause mortality. However, there is also clear evidence that PA acutely increases the risk of an adverse cardiovascular (CV) event and sudden cardiac death (SCD) significantly above levels expected at rest. Adverse CV events during PA may be triggered acutely by the physiological stress of exercise. This investigation will review the available literature describing the CV risks of exercise testing and PA participation in apparently healthy individuals. A systematic review of the literature was performed using electronic databases, including Medline, CINAHL, SPORT discus, EMBASE, Cochrane DSR, ACP Journal Club, and DARE; additional relevant articles were hand-picked and the final grouping was used for the review using the AGREE process to assess the impact and quality of the selected articles. Six hundred and sixteen relevant articles were reviewed with 51 being identified as describing adverse CV events during exercise and PA. Data suggests the risks of fatal and nonfatal events during maximal exercise testing in apparently healthy individuals rarely occur (approximately <0.8 per 10 000 tests or 1 per 10 000 h of testing). The incidence of adverse CV events is extremely low during PA of varying types and intensities, with data limited almost exclusively to fatal CV events, as nonfatal events are rarely reported. However, this risk is reduced by 25%–50% in those individuals who have prior experience with increased levels of PA, particularly vigorous PA. Throughout a wide age range, the risk of SCD and nonfatal events during PA remain extremely low (well below 0.01 per 10 000 participant hours), but both increasing age and PA intensity are associated with greater risk. In most cases of exercise-related SCD, undetected pre-existing disease is present and SCD is typically the first clinical event. The risks of an adverse CV event during exercise testing and PA are rare and are outweighed by the health benefits. Given this risk-benefit relationship, the PAR-Q is an appropriate method to identify those at higher risk across a wide age span and should be used in conjunction with appropriate clinical guidelines for guiding individuals towards graduated PA. There are not adequate data to describe the risks of PA in those individuals considered to be at higher risk but without cardiovascular disease.

The prevalence, distribution, and clinical outcomes of electrocardiographic repolarization patterns in male athletes of African/Afro-Caribbean origin

AIMS

Athletic training in male black athletes (BAs) is associated with marked ECG repolarization changes that overlap with hypertrophic cardiomyopathy (HCM). Differentiating between the two entities is prudent since BAs exhibit a higher prevalence of exercise-related sudden death from HCM compared with white athletes (WAs).

METHODS AND RESULTS

Between 1996 and 2010, 904 BAs underwent serial cardiac evaluations including ECG and echocardiography. Athletes exhibiting T-wave inversions were investigated further for HCM. Results were compared with 1819 WAs, 119 black controls (BCs), and 52 black HCM patients. Athletes were followed up for 69.7 ± 29.6 months. T-wave inversions were present in 82.7% HCM patients, 22.8% BAs, 10.1% BCs, and 3.7% WAs. In athletes, the major determinant of T-wave inversions was black ethnicity. T-wave inversions in BAs (12.7%) were predominantly confined to contiguous anterior leads (V1-V4). Only 4.1% of BAs exhibited T-wave inversions in the lateral leads. In contrast, both BCs and HCM patients exhibited lower prevalence of T-wave inversions in leads V1-V4 (4.2 and 3.8%, respectively) with most T-wave inversions in HCM patients (76.9%) involving the lateral leads. During follow-up one BA survived cardiac arrest and two athletes (one BA, one WA) were diagnosed with HCM. All three exhibited T-wave inversions in the lateral leads.

CONCLUSIONS

T-wave inversions in leads V1-V4 appear to represent an ethnic variant of 'athlete's heart'. Conversely, T-wave inversions in the lateral leads may represent the initial expression of underlying cardiomyopathy and merit further evaluation and regular surveillance.

Prevalence of electrocardiographic abnormalities in West-Asian and African male athletes

Objectives

To evaluate the electrocardiographic (ECG) characteristics of West-Asian, black and Caucasian male athletes competing in Qatar using the 2010 recommendations for 12-lead ECG interpretation by the European Society of Cardiology (ESC).

Design

Cardiovascular screening with resting 12-lead ECG analysis of 1220 national level athletes (800 West-Asian, 300 black and 120 Caucasian) and 135 West-Asian controls was performed.

Results

Ten per cent of athletes presented with ‘uncommon’ ECG findings. Black African descent was an independent predictor of ‘uncommon’ ECG changes when compared with West-Asian and Caucasian athletes (p<0.001). Black athletes also demonstrated a significantly greater prevalence of lateral T-wave inversions than both West-Asian and Caucasian athletes (6.1% vs 1.6% and 0%, p<0.05). The rate of ‘uncommon’ ECG changes between West-Asian and Caucasian athletes was comparable (7.9% vs 5.8%, p>0.05). Seven athletes (0.6%) were identified with a disease associated with sudden death; this prevalence was two times higher in black athletes than in West-Asian athletes (1% vs 0.5%), and no cases were reported in Caucasian athletes and West-Asian controls. Eighteen West-Asian and black athletes were identified with repolarisation abnormalities suggestive of a cardiomyopathy, but ultimately, none were diagnosed with a cardiac disease.

Conclusion

West-Asian and Caucasian athletes demonstrate comparable rates of ECG findings. Black African ethnicity is positively associated with increased frequencies of ‘uncommon’ ECG traits. Future work should examine the genetic mechanisms behind ECG and myocardial adaptations in athletes of diverse ethnicity, aiding in the clinical differentiation between physiological remodelling and potential cardiomyopathy or ion channel disorders.

Risk of sudden death among young individuals with J waves and early repolarization: putting the evidence into perspective

The presence of J waves and ST-segment elevation on the electrocardiogram (ECG), jointly termed "the early repolarization pattern," has traditionally been considered a marker of "good health." However, recent case control series and long-term population studies have established a statistically significant association between this ECG pattern and an increased risk for arrhythmic death. This finding has raised concern among physicians, who now are asked to estimate the "arrhythmic risk" following the incidental discovery of J waves on routine ECG. Therefore, we review the literature linking early repolarization with arrhythmic risk to place this "fear of J waves" in the right perspective. We found five case control studies (involving 331 patients with idiopathic ventricular fibrillation [VF] and 8,649 controls). All of these studies showed that J waves, particularly of large amplitude and recorded in multiple leads, are more prevalent among patients with idiopathic VF. We also found three large population studies (involving >17,000 individuals) looking at the prognostic value of early repolarization. Two of these studies showed that the presence of J waves >2 mm in amplitude in asymptomatic adults is associated with a threefold increased of arrhythmic death during very long-term follow-up. Individuals with J waves do have some degree of increased dispersion of repolarization that places them at increased risk for arrhythmic death, but only in the presence of additional proarrhythmic factors or triggers. A sensible approach for the asymptomatic patient with J waves is proposed.

Cost-effectiveness of preparticipation screening for prevention of sudden cardiac death in young athletes

BACKGROUND

Inclusion of 12-lead electrocardiography (ECG) in preparticipation screening of young athletes is controversial because of concerns about cost-effectiveness.

OBJECTIVE

To evaluate the cost-effectiveness of ECG plus cardiovascular-focused history and physical examination compared with cardiovascular-focused history and physical examination alone for preparticipation screening.

DESIGN

Decision-analysis, cost-effectiveness model.

DATA SOURCES

Published epidemiologic and preparticipation screening data, vital statistics, and other publicly available data.

TARGET POPULATION

Competitive athletes in high school and college aged 14 to 22 years.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Nonparticipation in competitive athletic activity and disease-specific treatment for identified athletes with heart disease.

OUTCOME MEASURE

Incremental health care cost per life-year gained.

RESULTS OF BASE-CASE ANALYSIS

Addition of ECG to preparticipation screening saves 2.06 life-years per 1000 athletes at an incremental total cost of $89 per athlete and yields a cost-effectiveness ratio of $42 900 per life-year saved (95% CI, $21 200 to $71 300 per life-year saved) compared with cardiovascular-focused history and physical examination alone. Compared with no screening, ECG plus cardiovascular-focused history and physical examination saves 2.6 life-years per 1000 athletes screened and costs $199 per athlete, yielding a cost-effectiveness ratio of $76 100 per life-year saved ($62 400 to $130 000).

RESULTS OF SENSITIVITY ANALYSIS

Results are sensitive to the relative risk reduction associated with nonparticipation and the cost of initial screening.

LIMITATIONS

Effectiveness data are derived from 1 major European study. Patterns of causes of sudden death may vary among countries.

CONCLUSION

Screening young athletes with 12-lead ECG plus cardiovascular-focused history and physical examination may be cost-effective.

PRIMARY FUNDING SOURCE

Stanford Cardiovascular Institute and the Breetwor Foundation.

Addition of the electrocardiogram to the preparticipation examination of college athletes

OBJECTIVE

Although the use of standardized cardiovascular (CV) system-focused history and physical examination is recommended for the preparticipation examination (PPE) of athletes, the addition of the electrocardiogram (ECG) has been controversial. Because the impact of ECG screening on college athletes has rarely been reported, we analyzed the findings of adding the ECG to the PPE of Stanford athletes.

DESIGN

For the past 15 years, the Stanford Sports Medicine program has mandated a PPE questionnaire and physical examination by Stanford physicians for participation in intercollegiate athletics. In 2007, computerized ECGs with digital measurements were recorded on athletes and entered into a database.

SETTING

Although the use of standardized CV-focused history and physical examination are recommended for the PPE of athletes, the addition of the ECG has been controversial. Because the feasibility and outcomes of ECG screening on college athletes have rarely been reported, we present findings derived from the addition of the ECG to the PPE of Stanford athletes. For the past 15 years, the Stanford Sports Medicine program has mandated a PPE questionnaire and physical examination by Stanford physicians for participation in intercollegiate athletics. In 2007, computerized ECGs with digital measurements were recorded on athletes and entered into a database.

MAIN OUTCOME MEASURES

Six hundred fifty-eight recordings were obtained (54% men, 10% African-American, mean age 20 years) representing 24 sports. Although 68% of the women had normal ECGs, only 38% of the men did so. Incomplete right bundle branch block (RBBB) (13%), right axis deviation (RAD) (10%), and atrial abnormalities (3%) were the 3 most common minor abnormalities. Sokolow-Lyon criteria for left ventricular hypertrophy (LVH) were found in 49%; however, only 27% had a Romhilt-Estes score of >or=4. T-wave inversion in V2 to V3 occurred in 7%, and only 5 men had abnormal Q-waves. Sixty-three athletes (10%) were judged to have distinctly abnormal ECG findings possibly associated with conditions including hypertrophic cardiomyopathy or arrhythmogenic right ventricular dysplasia/cardiomyopathy. These athletes were offered further testing but this was not mandated according to the research protocol.

RESULTS

Six hundred fifty-three recordings were obtained (54% men, 7% African American, mean age 20 years), representing 24 sports. Although 68% of the women had normal ECGs, only 38% of the men did so. Incomplete RBBB (13%), RAD (10%), and atrial abnormalities (3%) were the 3 most common minor abnormalities. Sokolow-Lyon criteria for LVH were found in 49%; however, only 27% had a Romhilt-Estes score of >or=4. T-wave inversion in V2 to V3 occurred in 7% and only 5 men had abnormal Q-waves. Sixty-five athletes (10%) were judged to have distinctly abnormal ECG findings suggestive of arrhythmogenic right ventricular dysplasia, hypertrophic cardiomyopathy, and/or biventricular hypertrophy. These athletes will be submitted to further testing.

CONCLUSIONS

Mass ECG screening is achievable within the collegiate setting by using volunteers when the appropriate equipment is available. However, the rate of secondary testing suggests the need for an evaluation of cost-effectiveness for mass screening and the development of new athlete-specific ECG interpretation algorithms.

Ethnic differences in physiological cardiac adaptation to intense physical exercise in highly trained female athletes

BACKGROUND

Ethnicity is an important determinant of cardiovascular adaptation in athletes. Studies in black male athletes reveal a higher prevalence of electric repolarization and left ventricular hypertrophy than observed in white males; these frequently overlap with those observed in cardiomyopathy and have important implications in the preparticipation cardiac screening era. There are no reports on cardiac adaptation in highly trained black females, who comprise an increasing population of elite competitors.

METHODS AND RESULTS

Between 2004 and 2009, 240 nationally ranked black female athletes (mean age 21+/-4.6 years old) underwent 12-lead ECG and 2-dimensional echocardiography. The results were compared with 200 white female athletes of similar age and size participating in similar sports. Black athletes demonstrated greater left ventricular wall thickness (9.2+/-1.2 versus 8.6+/-1.2 mm, P<0.001) and left ventricular mass (187.2+/-42 versus 172.3+/-42 g, P=0.008) than white athletes. Eight black athletes (3%) exhibited a left ventricular wall thickness >11 mm (12 to 13 mm) compared with none of the white athletes. All athletes revealed normal indices of systolic and diastolic function. Black athletes exhibited a higher prevalence of T-wave inversions (14% versus 2%, P<0.001) and ST-segment elevation (11% versus 1%, P<0.001) than white athletes. Deep T-wave inversions (-0.2 mV) were observed only in black athletes and were confined to the anterior leads (V(1) through V(3)).

CONCLUSIONS

Systematic physical exercise in black female athletes is associated with greater left ventricular hypertrophy and higher prevalence of repolarization changes than in white female athletes of similar age and size participating in identical sporting disciplines. However, a maximal left ventricular wall thickness >13 mm or deep T-wave inversions in the inferior and lateral leads are rare and warrant further investigation.

Effects of long-term physical activity on cardiac structure and function: a twin study

Previous studies have shown that athletic training or other physical activity causes structural and functional adaptations in the heart, but less is known how long-term physical activity affects heart when genetic liability and childhood environment are taken into account. The aim of this study was to investigate the effects of long-term physical activity vs. inactivity on cardiac structure and function in twin pairs discordant for physical activity for 32 years. Twelve same-sex twin pairs (five monozygotic and seven dizygotic, 50-67 years) were studied as a part of the TWINACTIVE study. Discordance in physical activity was initially determined in 1975 and it remained significant throughout the follow-up. At the end of the follow-up in 2007, resting echocardiographic and electrocardiographic measurements were performed. During the follow-up period, the active co-twins were on average 8.2 (SD 4.0) MET hours/day more active than their inactive co-twins (p < 0.001). At the end of the follow-up, resting heart rate was lower in the active than inactive co-twins [59 (SD 5) vs. 68 (SD 10) bpm, p=0.03]. The heart rate-corrected QT interval was similar between the co-twins. Also, there was a tendency for left ventricular mass per body weight to be greater and T wave amplitude in lead II to be higher in the active co-twins (18% and 15%, respectively, p=0.08 for both). Similar trends were found for both monozygotic and dizygotic twin pairs. In conclusion, the main adaptation to long- term physical activity is lowered resting heart rate, even after partially or fully controlling for genetic liability and childhood environment. Key pointsThe main adaptation to long-term physical activity is lowering of resting heart rate, even after controlling for genetic liability.VO2peak is increased in the active co-twins compared with their inactive co-twins and accordingly, also submaximal heart rates during the clinical exercise test are lower in physically active co-twins.There is a tendency for increased LVM per body weight and heightened T wave amplitude in the active co-twins.

Adding an electrocardiogram to the pre-participation examination in competitive athletes: a systematic review

No matter how rare, the death of young athletes is a tragedy. Can it be prevented? The European experience suggests that adding the electrocardiogram (ECG) to the standard medical and family history and physical examination can decrease cardiac deaths by 90%. However, there has not been a randomized trial to demonstrate such a reduction. While there are obvious differences between the European and American experiences with athletes including very differing causes of athletic deaths, some would highlight the European emphasis on public welfare vs the protection of personal rights in the USA. Even the authors of this systematic review have differing interpretation of the data: some of us view screening as a hopeless battle against Bayes, while others feel that the ECG can save lives. What we all agree on is that the USA should implement the American Heart Association 12-point screening recommendations and that, before ECG screening is mandated, we need to gather more data and optimize ECG criteria for screening young athletes.

Recommendations for interpretation of 12-lead electrocardiogram in the athlete

Cardiovascular remodelling in the conditioned athlete is frequently associated with physiological ECG changes. Abnormalities, however, may be detected which represent expression of an underlying heart disease that puts the athlete at risk of arrhythmic cardiac arrest during sports. It is mandatory that ECG changes resulting from intensive physical training are distinguished from abnormalities which reflect a potential cardiac pathology. The present article represents the consensus statement of an international panel of cardiologists and sports medical physicians with expertise in the fields of electrocardiography, imaging, inherited cardiovascular disease, cardiovascular pathology, and management of young competitive athletes. The document provides cardiologists and sports medical physicians with a modern approach to correct interpretation of 12-lead ECG in the athlete and emerging understanding of incomplete penetrance of inherited cardiovascular disease. When the ECG of an athlete is examined, the main objective is to distinguish between physiological patterns that should cause no alarm and those that require action and/or additional testing to exclude (or confirm) the suspicion of an underlying cardiovascular condition carrying the risk of sudden death during sports. The aim of the present position paper is to provide a framework for this distinction. For every ECG abnormality, the document focuses on the ensuing clinical work-up required for differential diagnosis and clinical assessment. When appropriate the referral options for risk stratification and cardiovascular management of the athlete are briefly addressed.

Electrocardiographic reference values in whippets

The aim of this study was to determine the electrocardiographic characteristics of whippets and to compare the results with published reference values for a general dog population. Electrocardiographic parameters from 105 healthy whippets were used to establish reference values for the breed. The most important differences compared to published reference values were the higher median R-wave amplitudes in leads II, CV(6)LL and CV(6)LU. For some parameters (P-wave amplitude, ST-segment deflection and T-wave amplitude in lead II; R-wave amplitude in CV(5)RL), a marked percentage of the whippet values were above the published maximum reference data. The results confirmed that whippets have electrocardiographic characteristics similar to those reported in athletic heart syndrome in humans. Some of these characteristics could be erroneously taken as evidence of cardiac disease and clinicians should be aware of these factors to prevent unnecessary investigations in healthy dogs.