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Paediatric athletes are not simply ‘mini adults’. While paediatric athletes do display physiological cardiac remodelling in response to exercise, distinguishing between physiology and pathology may be more difficult due to maturational development and variable disease penetrance. However, most current cardiac screening guidelines and policies focus on adult athletes. A recent review of athlete screening guidelines found very few provided specific advice for paediatric athletes, and that further data are needed from studies specific to paediatric athletes. Further, the authors emphasise the importance of building additional paediatric cardiology expertise in the care of young athletes.

A ‘paediatric athlete’ is usually defined as an individual aged 12–16 years participating in a team or individual sport with regular competition where there is a ‘high premium on excellence’ that involves regular, often intense, training. , Defining athletic status in terms of age of starting competitive activity, training hours, intensity, and level of performance is useful when assessing the degree of exercise-induced cardiac remodelling. The reason athletes are targeted for cardiac screening is based on the notion that among those who have an underlying predisposition for a heart condition, exercise per se may act as a trigger for cardiac arrhythmia and the potential for sudden cardiac arrest or death (SCA/D). There is evidence that training and competition can be stimuli to trigger phenotypic cardiac disease, leading to a higher risk of SCA/D in young competitive athletes compared to non-athletes and children.

Although the data supporting the implementation of cardiac screening in paediatric athletes are similar to that in adults, the optimal paediatric screening strategy is still debated. Investigating children can be challenging because maturation and development, particularly during puberty, must be taken into account when differentiating between physiological adaptation, growth and pathology. A recent study of 22 324 children aged 7–18 years, who underwent consecutive preparticipation screening, showed cardiac disorders associated with SCA/D were identified in 0.3%, with approximately one-third of diagnoses made at the first screening and two-thirds from subsequent examinations. Over 90% of the diseases were diagnosed in athletes aged 12 years or older. , Specifically, the target population of this document is defined as asymptomatic athletes <16 years, including those younger than 12 years of age, without cardiovascular conditions, such as congenital heart diseases (CHD) or inherited cardiac conditions already identified. In these latter cases, the specific European Society of Cardiology (ESC) guidelines must be followed.

This document is a collaboration between the European Association of Preventive Cardiology (EAPC) of the ESC and the Association for European Paediatric and Congenital Cardiology (AEPC). It follows the principles of the EAPC and AEPC scientific document committees in terms of evaluating evidence and providing advice. Clinical consensus statements were based on the strength of evidence, and consensus was reached by anonymous voting by members of the writing group using web-based software (Qualtrics). At least 80% agreement was required for acceptance, although authors with dissenting opinions were able to have these views included in the manuscript. The strength of advice is based on the following definitions in accordance with the ESC policy on consensus statements: When a statement was based on robust evidence, it was designated 4 stars. When a statement was predominantly based on expert opinion, it was assigned 3 stars when all the authors agreed (‘uniform consensus’). Statements were assigned 1 or 2 stars when >80%, but not all authors were in agreement. The distinction between 1 star and 2 stars was based on ‘some published evidence’ or ‘consensus opinion’, respectively. If consensus could not be reached, a statement was assigned a question mark, indicating an area of uncertainty.

sets out the key clinical consensus statements providing screening advice for paediatric athletes, indicating the strength of advice. Dissenting votes for statements that reached agreement are provided in Supplement 1. All advice in this document applies to paediatric athletes <16 years, including those younger than 12 years of age. While in many healthcare systems and jurisdictions the paediatric age is defined as below the age of 18 years, based on evidence of cardiac adaptation to exercise, but also historical concepts and consensus of other recommendation and guideline papers on athlete screening, for athletes over the age of 16 years, adult documents should be used. and the present a list of normal, borderline and abnormal ECG findings in paediatric athletes <16 years, including those younger than 12 years of age.

Establishing a habit of physical activity in childhood and adolescence has numerous health benefits, including improved cognitive function, bone and cardiometabolic health. The World Health Organisation recommends children aged 5–17 years undertake an average of 60 min/day of moderate to vigorous physical activity. While 81% of adolescents fail to meet the guidelines, 40–43% of children and adolescents worldwide participate in organised sport. This percentage is as high as 90% in Denmark, and around 60% in the USA. Where available, data show that 64% of participants in organised sports are under the age of 20 years, with 28% aged 10–14 years. Though conversion rates from youth to professional/elite sport are low (0.04% in football), there has been a continued drive towards early specialisation and professionalisation, with significant resources invested in identifying and developing future talented athletes. The increase in competitiveness, training loads, and competitive volumes without adequate time for recovery leads to concerns of an increased prevalence of injuries and health problems.

The International Olympic Committee and the American Academy of Paediatrics have cautioned against early sports specialisation and the year-round focus on one sport. Nevertheless, in the United Kingdom, the football performance pathway starts at the age of 8, with those at 13 years of age undertaking 10–12 h of weekly training. In traditional early specialisation sports such as gymnastics and swimming, paediatric athletes regularly undertake 15 + hours of training per week. A study of elite college athletes showed that although early sport specialisation did confer increased risk of injury, such athletes were more likely to gain a scholarship, further driving early childhood talent identification and professionalisation.

In addition to traditional sports, a new category of electronic sport (known as e-sports, esports, or exergames) is gaining momentum. Professional gamers often practice for many hours per day and participate in dedicated international competitions. Participants demonstrate increases in metabolic rate, energy expenditure and cardiopulmonary function, although the exercise physiology and cardiovascular function of e-athletes remains poorly studied. Emerging adverse events related to e-sports include internet gaming disorders, mental health and emotional impairments, long-lasting screen vision, parasympathetic inhibition, increased food intake, sleep deprivation, impairment in heart rate variability and potential cardiovascular risks. No specific requirements or a formal pre-participation screening for e-sport players have been proposed by scientific societies, and the research in this emerging area is still very limited. In a recently published proposal, the preparticipation screening should include not only cardiovascular assessment for the prevention of exercise-induced cardiac death, but also ophthalmologic, neurologic and psychological assessment and a correct training plan and an injury prevention strategy should be included. Paediatric e-sport players may be at a higher risk of exposure to inappropriate content, including violence, bullying, internet addiction, isolation, exposure to unhealthy lifestyle habits, and sleep deprivation, compared to adult e-sport players, a more comprehensive evaluation may be appropriate, and we wish to raise awareness on this emerging area.

Diagnosis of cardiomyopathies and arrhythmias can be very challenging due to differences in their phenotypic expression in childhood. Inherited cardiomyopathies often remain asymptomatic and subclinical in childhood, showing a rapid increase in phenotypic presentation in the second decade of life. However, many inherited or acquired paediatric arrhythmic diseases can be successfully diagnosed by screening, including electrocardiogram (ECG) and family history, especially if performed by professionals with paediatric cardiology expertise.

Physiological remodelling of the paediatric athlete’s heart resembles the physiological adaptation in adults, with harmonious enlargement of all four cardiac chambers, it is quantitatively less prominent than in adults. While pre-pubertal children generally exhibit less significant cardiac remodelling, ,, factors such as maturation, growth and widely varying training volumes and intensities can hinder a clear differentiation between physiology and pathology. Conversely, adolescents in the peri-pubertal or post-pubertal stages may already show features of the athlete’s heart, especially if engaged in high-intensity sports activity with a pronounced aerobic component (e.g. running or swimming). While it is true that training modalities influence the type of cardiac remodelling, with more pronounced eccentric hypertrophy in endurance sports, recent data have questioned the validity of the classic Morganroth hypothesis in adult athletes. Therefore, while an understanding of this concept can aid in the cardiac assessment of an athlete, it is less useful to strictly categorise cardiac adaptation in athletes by sporting discipline, especially in paediatric athletes, where adaptation is present, but often less pronounced. ,

Several consensus documents and reviews aid in differentiating between an athlete's heart and cardiomyopathies, but the distinction between these conditions remains challenging. ,, A cardiomyopathy may be suggested by a positive family history, symptoms reported by the athlete, abnormalities on physical examination, or alterations in the ECG. In children, these changes can be subtle and knowledge of the nuances in cardiac adaptation to exercise in different age groups and the distinct presentations of early cardiomyopathies can enhance diagnostic accuracy. Absolute values of left ventricular (LV) or right ventricular (RV) thickness and size are rarely helpful in detecting pathology. Z-scores employing an algorithm that accounts for height and weight and normative population data can be discriminative, as can modern functional echocardiography tools such as 2D strain, for both RV , and LV cardiomyopathies. Consequently, in a young athlete with a positive family or past medical history or ECG repolarisation abnormalities, even a borderline-enlarged left ventricle may be indicative of a developing pathology. This underscores the importance of careful and longitudinal evaluation and a high index of suspicion when screening paediatric athletes, while avoiding false positive results. When in doubt, consultation with experts in paediatric cardiomyopathies is crucial.

SCA/D in children is rare, but accounts for up to 10% of mortality after the first year of life. In the US general population, the incidence of sudden cardiac death is the lowest in children aged 1–10 years (0.42/100 000), with a slight increase in those aged 11–18 years (0.52/100 000), and further increases up to the age of 34 years (2.76/100 000). Therefore, adolescence, particularly the pubertal growth spurt, is an important phase of rapid change that can facilitate the transition from conceived to overt clinical phenotypes of genetic diseases such as cardiomyopathies and channelopathies. This is also an age group where the intensity of sport and training requirements increases significantly. The reported incidence of SCA/D in young athletes aged 8–15 years is 0.7/100 000/year. These tragic events are rarer in individuals aged 8–11 years, with the incidence rising in those aged 12–15 years (1.2/100 000/year). Often, there are no warning signs, with only a minority experiencing symptoms prior to death. An estimated 1 in 300 children engaged in competitive sport has a cardiac condition at risk of SCA/D.

Sudden arrhythmic death syndrome (SADS), myocardial diseases and coronary artery anomalies are the most common aetiologies of SCA/D in adolescents. Children who suffer sudden death are more likely than adults to have a structurally normal heart at the post-mortem examination. In 52% of cases of sudden death in children aged <18 years, the post-mortem examination was consistent with SADS with a structurally normal heart, suggesting a possible underlying primary arrhythmia syndrome. In contrast, SADS occurred in 42% of adult athletes aged 18–35 and in 26% of adults >35 years. Coronary artery anomalies were the second most common cause of sudden death (17% of cases) in a large cohort of young American athletes.

Cardiac conditions associated with SCA/D are often identified through screening with a personal/family history assessment and resting 12-lead ECG. The yield of screening is lower in younger children (0.05%), increasing to 0.1–0.3% in early adolescence. , Serial screening appears to improve the diagnostic yield. ,, For example, in an 11-year study of 22 324 children aged 7–18 years who underwent serial cardiac screening, 69 cases (0.3%) of conditions associated with SCA/D were identified, but 91% of these were identified in children ≥12 years, and 64% were identified only on repeat evaluation. The rise in SCA/D during adolescence is an argument in favour of screening in peri-pubertal individuals. In addition, recent studies have shown that young individuals with cardiomyopathies (10–15 years of age) are at higher risk of SCA/D during exercise compared to adults with the disease. ,

However, there are some caveats which must be taken into account when screening this age group. First, accurate interpretation requires specific expertise in paediatric athlete ECGs. For example, anterior T-wave inversion (TWI) beyond V2, which is currently regarded as an abnormal feature in most adult athletes, is a common peri-pubertal physiological phenomenon, especially before the pubertal growth spurt. Secondly, screening in adolescents has a lower diagnostic yield compared to older athletes, where the phenotypic expression of heritable cardiac disease may be clearer and more overt. Finally, screening in this age group leads to a greater number of ‘grey’ cases compared to older athletes. ‘Grey cases’, and all abnormal results (including false positives), require further evaluation, which has implications in terms of cost, time and potential anxiety for the athlete and their family. Strategies to reduce the burden of false positive results include: accurate interpretation of ECGs in accordance with paediatric-specific athlete criteria, providing a clear pathway for those requiring further evaluation, and ensuring all follow-up tests are completed and communicated in a timely manner. Conversely, even a best practice programme will miss some cases, as not all conditions are visible on an ECG, or may vary over time. It is important to inform athletes (and their parents) of the limitations of screening and to report any future symptoms.

Marked heterogeneity exists across different countries in paediatric cardiac screening practices and protocols, as there are insufficient data to support a particular strategy. Some countries conduct broad, general screening examinations of all children, commencing at the age of 6 years, and repeated at age 12. These examinations may or may not include an ECG. Italy introduced a programme of ECG screening of newborns in the 4th week of life for long QT syndrome, which causes approximately 10% of sudden infant deaths. Several countries have implemented systematic screening of community-level athletes, often commencing in early adolescence. In Italy, this mandatory screening includes an ECG and simplified stress ECG, with commencement age depending on the sport (usually between 8 and 12 years). In contrast, many countries have no systematic screening programmes for paediatric community athletes or the general school-aged population, meaning that the only screening programmes are conducted by sporting organisations and generally limited to elite athletes.

This document advises that cardiac screening of paediatric athletes with personal and family medical history, physical examination and 12-lead resting ECG should be performed and should start no later than the age of 12 years ( ). All advice in this document applies to paediatric athletes <16 years, including those younger than 12 years of age. The age of 12 years is a common starting age for most competitive sports, the age at which inherited cardiomyopathies may manifest structurally, and when there is a discernible increase in SCA/D in population studies. , It is noted that some countries conduct national screening programmes which start earlier than 12 years of age or between the ages of 14–16 years. Countries with these programmes can continue to follow national guidance. Implementing a screening programme requires ensuring the availability of necessary healthcare resources. One transthoracic echocardiogram may be appropriate to identify high-risk structural cardiac diseases not identifiable on ECG (e.g. congenital anatomic coronary artery anomalies, valve disease and aortic disease). If an echocardiogram is performed, it is important that the appropriate infrastructure for baseline diagnostic assessments is in place, as well as availability of specific paediatric expertise and resources for appropriate follow-up.

In healthy athletes, repeat screening is advised every 2 years until the age of 16 years. After this, advice for adult athletes should be followed. If definitive or suspicious pathological findings are identified on the preliminary screening tests, an echocardiogram and stress ECG are advised as first-line examinations, as clinically indicated. sets out the indications for performing an echocardiogram in paediatric athletes. Structural and functional echocardiograms should be performed in accordance with international paediatric recommendations. Performing and interpreting echocardiography in paediatric athletes requires expertise in congenital and paediatric conditions.

A structured approach to clinical cardiovascular assessment of the paediatric athlete should include an exercise and training history, personal and family medical history and physical examination. Parents and guardians should be fully informed of the screening process, and their involvement provides the opportunity to identify major issues, build rapport and provide education. However, screening with personal/family history and physical examination alone has been reported to have a sensitivity of around 20% and specificity of 68%, both of which are substantially lower than when an ECG is included. , The current International Criteria have a sensitivity of 97–99% and specificity of 86% in older adolescent soccer players aged 16.4 ± 1.2 years. In athletes aged 12–14 years, the current International Criteria have a lower sensitivity (57%), but a higher specificity (98%).

The medical history should enquire about exercise and non-exercise related cardiovascular symptoms such as chest pain, disproportionate dyspnoea on exercise, palpitations or syncope. The history should include current medications, including supplements, and details of major illnesses requiring hospital admission or surgery. Common conditions, such as asthma, should be noted, as they may overlap with symptoms of cardiac disease. Details of the athlete’s exercise history and current exercise participation should include type, frequency, intensity and duration of exercise sessions. Sleep quality and duration, as well as the amount of screen time, should be assessed.

A family history should be taken, concentrating on the presence of early onset cardiovascular disease in a first or second degree relative, including inherited cardiomyopathies and arrhythmia syndromes, ischaemic heart disease, aortic dissection, connective tissue disorders, diagnosis of a condition associated with SCA/D, exercise-related arrhythmias and syncope and SCA/D in a relative aged <40 years. Such details are important, but may not always be available. Thus, lay terms such as ‘heart attack’ may be applied to many conditions ranging from myocardial infarction to sudden arrhythmic death. The implantation of a pacemaker may actually refer to an implantable defibrillator. Similarly, unexplained car accidents or deaths while swimming can be due to an arrhythmic cause. If the athlete has a first-degree relative affected by an inherited cardiac condition with a pathogenic/likely pathogenic variant identified, specific guidelines for pre-test genetic counselling should be followed. , A cardiovascular examination should be conducted, including measuring blood pressure, palpation of dorsal pedis pulses to exclude aortic coarctation and a general examination for signs of a syndromal anomaly that might have cardiovascular implications, e.g. Noonan or Marfan’s syndrome ( ).

ECGs in paediatric athletes demonstrate both physiological adaptation of the heart to regular exercise and growth and maturation. , This is reflected in parameters such as lower resting heart rate, longer PR interval and QRS duration, and changes in repolarisation. Several common ECG findings in adult athletes are also present in paediatric athletes, such as sinus bradycardia, incomplete right bundle branch block (RBBB), anterior TWI, first-degree heart block and early repolarisation. , Normative values and expression of ECG variables by z-scoring have been proposed for children and may help in high-volume screening. A detailed understanding of these changes is critical for distinguishing between benign training-induced remodelling and potentially life-threatening cardiac conditions. However, while the International Criteria for Athlete ECG Interpretation have been validated in adults, they have a lower sensitivity in paediatric athletes. A revision of the International Criteria was recently proposed and adapted for paediatric athletes, although it requires validation and refinement. A list of suggested ECG recommendations for paediatric athletes is presented in .

provides proposed definitions of normal ECG findings in paediatric athletes. In the absence of symptoms or relevant family history, the following ECG parameters are regarded as normal in paediatric athletes and do not require any further evaluation. sets out borderline ECG findings in paediatric athletes. Further evaluation is determined on a case-by-case basis if one or more borderline findings are present. This recognises that not all borderline findings definitely require further evaluation and allows individual discretion and judgement, reflecting current clinical practice. The ECG parameters in are regarded as abnormal in paediatric athletes and further evaluation is advised ( ).

The cut-off for marked bradycardia differs between paediatric and adult athletes. For paediatric athletes, a threshold of 40 bpm is proposed. Therefore, heart rates >40 bpm are regarded as normal in paediatric athletes, if in sinus rhythm. Beyond bradycardia, respiratory sinus arrhythmia, junctional escape rhythm, and isorhythmic dissociation may be found in paediatric athletes due to increased vagal tone. These are normal variants in the absence of symptoms such as dizziness, syncope, or fatigue. In borderline cases, mild aerobic activity at the bedside or formal exercise testing can be useful to demonstrate normal sinus node activity with restoration of sinus rhythm and a normal chronotropic competence.

Early repolarisation is common in paediatric athletes. Although it is more prevalent in athletes (and particularly in those engaged in endurance sports), it is also found in sedentary children due to age-related enhanced vagal tone. All patterns of early repolarisation are regarded as normal, and no further investigations are needed in the absence of symptoms or family history.