Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD.

Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural, or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly over the last decade; pushed by a growing body of scientific data that both tests proposed criteria sets and establishes new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington, to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD.

Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural, or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly over the last decade; pushed by a growing body of scientific data that both tests proposed criteria sets and establishes new evidence to guide refinements. On February 26-27, 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington, to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD.

244Word Count: 4664 ABSTRACT Aim: To describe the electrocardiographic (ECG) and echocardiographic manifestations of the paediatric athlete's heart, and examine the impact of age, race and sex upon cardiac remodelling responses to competitive sport. Design: Systematic review and meta-analysisData sources: Six electronic databases were searched to May 2016: MEDLINE, PubMed, EMBASE, Web of Science, CINAHL and SPORTDiscus.Inclusion criteria: 1) Male and/or female competitive athletes, 2) participants aged 6-18 years, 3) original research article published in English language.Results: Data from 14,278 athletes and 1,668 non-athletes were included for qualitative (43 articles) and quantitative synthesis (40 articles). Paediatric athletes demonstrated a greater prevalence of training-related and training-unrelated ECG changes than non-athletes. Athletes ≥14 years were 15.8 times more likely to have inferolateral T-wave inversion than athletes <14 years. Paediatric black athletes had significantly more training-related and training-unrelated ECG changes than Caucasian athletes. Age was a positive predictor of left ventricular (LV) internal diameter during diastole, interventricular septum thickness during diastole, relative wall thickness and LV mass. When age was accounted for, these parameters remained significantly larger in athletes than non-athletes. Paediatric black athletes presented larger posterior wall thickness during diastole (PWTd) than Caucasian athletes. Paediatric male athletes also presented with larger PWTd than females. Conclusions:The paediatric athlete's heart undergoes significant remodelling both before and during 'maturational years'. Paediatric athletes have a greater prevalence of training related and training-unrelated ECG changes than non-athletes, with age, race and sex mediating factors on cardiac electrical and LV structural remodelling. Word count: 244 What is already known? Chronic training loads are associated with a number of electrophysiological, structural and functional cardiac adaptations in adult athletes.  Race and sex significantly impact upon the cardiac remodelling of the adult athlete's heart.  Paediatric athletes undergo significant growth and maturational changes; but unlike known musculoskeletal changes, there is limited information regarding how the heart may adapt to training before, during and after puberty. What are the new findings? Paediatric athletes were up to 13 times more likely to have deep T-wave inversion (TWI) (≥2mm) than age-matched non-athletes  Paediatric athletes ≥14 years of age were up to 16 times more likely to have inferolateral TWI (warranting further investigation) than athletes <14 years  Paediatric black athletes were up to 36 times more likely to have extended anterior TWI (leads V1-V4) than Caucasians.  Even after accounting for age, left ventricular structural parameters were larger among paediatric athletes than paediatric non-athletes

BackgroundAn increasing number of sporting bodies report unacceptably high levels of false-positive ECGs when undertaking pre-participation cardiac screening. To address this issue, modified ECG interpretation criteria have become available for use within athletes.ObjectiveThis study assessed the accuracy of the new 2014 ‘Refined Criteria’ against the 2013 Seattle Criteria and the 2010 European Society of Cardiology (ESC) recommendations in a cohort of Arabic, black and Caucasian athletes.Methods2491 male athletes (1367 Arabic, 748 black and 376 Caucasian) undertook pre-participation screening including a 12-lead ECG, with further investigation(s) upon indication.ResultsTen athletes (0.4%) were identified with cardiac pathology; seven with hypertrophic cardiomyopathy (HCM; five black and two Arabic) and three Arabs with Wolff–Parkinson–White syndrome (WPW). All three ECG criteria were 100% sensitive identifying all cases of HCM and WPW. The 2014 Refined Criteria reduced (p<0.0001) the prevalence of an abnormal ECG to 5.3% vs 11.6% (Seattle Criteria) and 22.3% (2010 ESC recommendations). The 2014 Refined Criteria significantly (p<0.0001) improved specificity (94.0%) across all ethnicities compared with the Seattle Criteria (87.5%) and ESC recommendations (76.6%). Black athletes continue to present a higher prevalence (p<0.0001) of abnormal ECGs compared with Arabic and Caucasian athletes (10% vs 3.6% and 2.1%).ConclusionsThe 2014 Refined Criteria for athlete ECG interpretation outperformed both the 2013 Seattle Criteria and the 2010 ESC recommendations by significantly reducing the number of false-positive ECGs in Arabic, black and Caucasian athletes while maintaining 100% sensitivity for serious cardiac pathologies.

Background— Pathological T-wave inversion (PTWI) is rarely observed on the ECG of healthy athletes, whereas it is common in patients with certain cardiac diseases. All ECG interpretation guidelines for use within athletes state that PTWI (except in leads aVR, III and V1 and in V1–V4 when preceded by domed ST segment in asymptomatic Afro-Caribbean athletes only) cannot be considered a physiological adaptation. The aims of the present study were to prospectively determine the prevalence of cardiac pathology in athletes presenting with PTWI, and to examine the efficacy of cardiac magnetic resonance in the work-up battery of further examinations. Methods and Results— Athletes presenting with PTWI (n=155) were investigated with clinical examination, ECG, echocardiography, exercise testing, 24h Holter ECG, and cardiac magnetic resonance. Cardiac disease was established in 44.5% of athletes, with hypertrophic cardiomyopathy (81%) the most common pathology. Echocardiography was abnormal in 53.6% of positive cases, and cardiac magnetic resonance identified a further 24 athletes with disease. Five athletes (7.2%) considered normal on initial presentation subsequently expressed pathology during follow-up. Familial history of sudden cardiac death and ST-segment depression associated with PTWI were predictive of cardiac disease. Conclusions— PTWI should be considered pathological in all cases until proven otherwise, because it was associated with cardiac pathology in 45% of athletes. Despite echocardiography identifying pathology in half of these cases, cardiac magnetic resonance must be considered routine in athletes presenting with PTWI with normal echocardiography. Although exclusion from competitive sport is not warranted in the presence of normal secondary examinations, annual follow-up is essential to ascertain possible disease expression.

Severely 25(OH)D-deficient athletes present significantly smaller cardiac structural parameters than insufficient and sufficient athletes. Future research should investigate the precise mechanism(s) causing cardiac hypertrophy with increases in serum 25(OH)D in healthy athletes.

Arabic athletes present significantly smaller cardiac dimensions than Black African and Caucasian athletes. There was no significant difference between the frequency of an uncommon and training-unrelated ECG between Arabic and Caucasian athletes. Therefore, the use of ESC guidelines for the interpretation of an athlete's ECG is clinically relevant and acceptable for use within Arabic athletes.