Atrial chamber remodelling in healthy pre-adolescent athletes engaged in endurance sports: A study with a longitudinal design. The CHILD study

Your Heart Can't See What Sneakers You Are Wearing: Exercise Training Load in Endurance Athletes Is Inadequately Quantified in Sports Cardiology

BACKGROUND

Training load may be an important factor underlying the (patho-)physiologic cardiovascular adaptations from endurance exercise. Yet, quantifying training load remains challenging due to the complexity of its components (Frequency, Intensity, Time, and Type [FITT]). In this systematic review we evaluate how training load has been quantified in sports cardiology studies and provide recommendations for how this can be improved.

METHODS

A comprehensive search was conducted across PubMed and EMBASE up to October 2024. Studies involving "sports cardiology," "training load," and "endurance sport" were included. Data extraction included study characteristics, training load assessment methods, cardiovascular outcomes, and athlete profiles.

RESULTS

A total of 62 studies with 1,060,700 participants were included in our review. The majority of studies (59.7%) focused on exercise-induced cardiac remodelling, with other topics being cardiac arrhythmias (12.9%), cardiac autonomic adaptation (3.2%), exercise dose-response (6.5%), and coronary heart disease (17.7%). Training load was primarily quantified by questionnaires (58.1%), whereas heart rate monitoring, a more objective measure, was used in only 1.6% of the studies. All studies reported exercise type, but only 19.4% measured all FITT components.

CONCLUSIONS

There is a lack of uniformity in the assessment of key FITT variables to quantify training load within the field of sports cardiology, with many studies relying on subjective or incomplete methods. As cardiology moves into the precision medicine era, researchers and clinicians should seek to obtain objective training load information from their athletes according to the FITT framework, and data from use of objective wearable devices represent the optimal way to do this.

The MuCAYAplus Study-Influence of Physical Activity and Metabolic Parameters on the Structure and Function of the Cardiovascular System in Young Athletes

Exercise has a significant impact on the cardiovascular (CV) health of children and adolescents, with resultant alterations in CV structure and function being evident, even at an early age. Engagement in regular, moderate physical activity (PA) is associated with long-term CV health benefits and a reduced risk of CV disease and mortality later in life. However, competitive sports often involve PA training intensities that are beyond recommended levels for young athletes, potentially leading to adverse CV outcomes. This situation emphasizes the importance of early monitoring of CV status, to prevent detrimental adaptations to intense physical exercise. The Munich Cardiovascular Adaptations in Young Athletes Study (MuCAYAplus; NCT06259617) aims to investigate the as-yet-unclear adaptations to intense exercise that occur in young athletes. The study focuses on various factors, including CV health, PA, cardiopulmonary performance, body composition, eating habits, and biochemical markers. In this longitudinal, prospective study, a sample of 250 young competitive athletes (aged 10-17 years) will undergo yearly examinations at the Institute of Preventive Pediatrics at the Technical University of Munich (TUM), over the span of 3 years. The testing protocol includes the following: anthropometric measurements; basic medical examinations; electrocardiography, with blood-pressure and pulse-wave analysis; echocardiography; sonography of the carotid artery; blood sampling for laboratory analysis; cardiopulmonary exercise testing on a bicycle ergometer; and participant completion of questionnaires regarding PA (the Motorik-Modul Longitudinal Study PA Questionnaire [MoMo-PAQ]) and nutrition. Areas that are not yet fully understood are how exercise influences cardiac and vascular remodeling during long-term exercise, and how different biochemical and metabolic parameters, body composition, and nutrition impact such adaptations. The MuCAYAplus study seeks to address these gaps in knowledge and provide comprehensive evidence on the longitudinal effects of exercise on the CV system of young athletes.

Normal ranges of left atrial phasic strains and strain rates by 2D speckle-tracking echocardiography in pediatrics: a systematic review and meta-analysis

Establishing normal values of left atrial (LA) phasic strains and strain rates is essential for distinguishing between normal and abnormal functions, determining the degree of abnormality, and understanding the clinical significance of reported values in pediatrics. This meta-analysis aimed to establish normal values of two-dimensional speckle-tracking echocardiography (2DSTE)-derived LA phasic strains and strain rates in the pediatric population and identify the sources of inter-study heterogeneity for these values. A comprehensive search of PubMed, Scopus, and Embase databases was conducted using keywords such as "left atrial/left atrium," "strain/speckle/deformation," and "echocardiography" combined with pediatric age categories. Inclusion criteria comprised English-language human studies involving healthy subjects under 18 years of age. Subjects were categorized as neonates (up to 1 month), infants (1-12 months), and children (1-18 years). A random-effects model was applied to determine 2DSTE-derived LA strains and strain rates, and a meta-regression analysis was performed to investigate inter-study heterogeneity. Our analysis included 17 studies involving 1448 healthy subjects. For children, the mean values of LA strains during the reservoir, conduit, and contraction phases were 47.3% (95% CI 42.5-52.1%), 32.8% (95% CI 27.8-37.8%), and 12% (95% CI 10.0-14.1%), respectively. The mean values for LA strain rates were 2.4 s-1 (95% CI 1.1-3.8 s-1), 4.3 s-1 (95% CI 0.6-8.0 s-1), and 2.4 s-1 (95% CI 0.4-4.5 s-1), respectively. Inter-study heterogeneity for 2DSTE-derived LA phasic strains and strain rates was attributed to factors such as the number of study participants, publication year, software utilized, gating methods, the number of analyzed segments, the geographical region of the study, and heart rate. This study established the normal range of 2DSTE-derived LA phasic strains and strain rates. Additionally, inter-study heterogeneity was found to be influenced by various demographic, physiologic, and methodological factors.

Determinants of supraventricular extra beats in elite athletes practicing different sporting disciplines

BACKGROUND

Supraventricular extra beats (SVEB) are frequently observed in athletes but data on significance, prognostic role and correlation with cardiac remodeling are contrasting. It is uncertain whether SVEB may indicate the development of more complex arrhythmias and the need for closer monitoring is undetermined. The aim was to assess the prevalence and clinical significance of BESV in Olympic athletes of different sporting disciplines, evaluating potential correlations with cardiac remodeling and clinical features.

METHODS

We enrolled athletes who participated at 2012-2022 Olympic Games, submitted to physical examination, blood tests, echocardiography and exercise tests, categorized into power, skills, endurance and mixed disciplines.

RESULTS

We studied 1492 elite athletes: 56% male individuals, mean age 25.8 ± 5.1 years; 29.5% practiced power, 12.3% skills, 21% endurance and 37.2% mixed disciplines. At exercise-stress tests, 6.2% had SVEB, mostly single beats. SVEB were not influenced by anthropometrics or blood test results. They were more common in male individuals (77.4 vs. 54.6%, P < 0.0001) and older athletes (27.1 ± 5.7 vs. 25.7 ± 5.1, P = 0.01). In male athletes with SVEB, higher left atrial volumes were observed (24.2 ± 7.3 vs. 22.2 ± 7.1 ml/m2, P = 0.03). No differences were found in terms of sporting discipline: despite larger left atrial dimensions in aerobic disciplines, SVEB rates were similar in different sporting disciplines (6.1% endurance, 6.3% mixed, 5.2% power and 8.7% skills; P = 0.435).

CONCLUSION

SVEB were more common in older, male athletes and associated with higher left atrial volume (especially in male individuals) regardless of sport practiced. Athletes with greater left atrial volume and SVEB are supposed to have higher risk, in middle age, of developing more complex arrhythmias.

Effects of Swimming Exercise on Early Adolescents' Physical Conditioning and Physical Health: A Systematic Review

BACKGROUND/OBJECTIVES

Swimming is a popular and cost-effective way to prevent sedentary behavior and improve physical conditioning and health during early adolescence. However, information on its impact and benefits on daily life activities is lacking. This systematic review aims to summarize the chronic effects of swimming on physical conditioning and physical health outcomes in early adolescents.

METHODS

The PRISMA 2020 guidelines were followed and PubMed, Scopus, Web of Science, and International Symposium of Biomechanics and Medicine in Swimming proceedings databases were searched. Eligibility criteria were defined on the PICOS framework (healthy adolescents in early puberty, swimming programmes or training, passive or active control groups, general effects on physical conditioning or health, longitudinal) and risk of bias was assessed using RoBANS 2.

RESULTS

From 2365 records, 20 non-randomized studies met the defined criteria. High heterogeneity in sample size and intervention was observed. While studies related to physical conditioning (n = 5) focused on physiological variables and muscular function, the evidence regarding physical health outcomes (n = 15) explored bone accrual, haemodynamics, body composition, musculoskeletal system, and lung growth. High overall risk of bias (70%) was observed due to strict criteria.

CONCLUSIONS

Swimming exercise seems to improve cardiorespiratory fitness, cardiac output, haemodynamics, heart growth, motor performance, and body composition of early adolescents. Despite clear evidence that exists on these chronic effects, research on bone health, postural deficit, motor skills, and sleep quality is still missing.

The athlete's heart: insights from echocardiography

The manifestations of the athlete's heart can create diagnostic challenges during an echocardiographic assessment. The classifications of the morphological and functional changes induced by sport participation are often beyond 'normal limits' making it imperative to identify any overlap between pathology and normal physiology. The phenotype of the athlete's heart is not exclusive to one chamber or function. Therefore, in this narrative review, we consider the effects of sporting discipline and training volume on the holistic athlete's heart, as well as demographic factors including ethnicity, body size, sex, and age.

Long-Term Sports Practice and Atrial Fibrillation: An Updated Review of a Complex Relationship

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice, and it is an enormous burden worldwide because of its high morbidity, disability and mortality. It is generally acknowledged that physical activity (PA) is strongly associated with a significant reduction in the risk of cardiovascular (CV) disease and all-cause mortality. Moreover, it has been observed that moderate and regular physical activity has the potential to reduce the risk of AF, in addition to improving overall well-being. Nevertheless, some studies have associated intense physical activity with an increased risk of AF. This paper aims to review the main related literature to investigate the association between PA and AF incidence and draw pathophysiological and epidemiological conclusions.

Training intensity influences left ventricular dimensions in young competitive athletes

Background

In young athletes, exercise causes changes in the heart that include growth in wall thickness and mass of the left ventricle and expansion of the heart’s chambers. The heart’s function is either preserved or enhanced, but this may change to the opposite over time.

Objective

This study aimed to assess structural and functional cardiac adaptations in relation to exercise training time, intensity, and performance in young competitive athletes.

Methods

A total of 404 children and adolescents (14.23 ± 2.0 years, 97 females) were enrolled in the Munich Cardiovascular Adaptations in Young Athletes Study (MuCAYA-Study). Eighty-five participants were examined two times a year. Two-dimensional echocardiography was performed to assess left ventricular structure and function. Training time and intensity was measured with the MoMo physical activity questionnaire, maximum aerobic capacity by cardiopulmonary exercise testing, and strength with the handgrip strength test.

Results

Maximum aerobic capacity significantly influenced interventricular septal thickness in diastole. Training intensity significantly influenced left ventricular internal diameter in diastole and systole, and left ventricular mass indexed to body surface area. Within one year, interventricular wall thickness, relative wall thickness and left ventricular mass, indexed to body surface area and height, increased significantly. Training intensity and aerobic capacity contributed to cardiac adaptations in young competitive athletes, as represented by altered structural parameters but preserved cardiac function. Within a year, however, structural changes and a decline in diastolic performance were observed within the longitudinal sub-sample.

Conclusion

Our results confirm the hypothesis that cardiac adaptations to exercise occur at a young age. Cardiac adaptation in our cohort was influenced by exercise intensity and maximum aerobic capacity.

Age impacts left atrial functional remodeling in athletes

Aim

Age-associated changes in cardiac filling and function are well known in the general population. Yet, the effect of aging on left atrial (LA) function, and its interaction with left ventricular (LV) adaptation, remain less described when combined with high-intensity chronic training. We aimed to analyze the effects of aging on LA and LV functions in trained athletes.

Methods and results

Ninety-five healthy highly-trained athletes referred for resting echocardiography were included. Two groups of athletes were retrospectively defined based on age: young athletes aged <35 years (n = 54), and master athletes aged ≥35 years (n = 41). All subjects were questioned about their sports practice. Echocardiographic analysis of LV systolic and diastolic functions (2D-echo, 3D-echo, and Doppler), as well as LA 2D dimensions and phasic deformations assessed by speckle tracking, were analyzed. Master athletes (mean age = 46.3 ± 8.3 years, mean duration of sustained training = 13.7 ± 8.9 years) exhibited significantly stiffer LV and LA with reduced LV early diastolic functional parameters (ratio E/A, peak e’, and ratio e’/a’), LA reservoir and conduit strain, whereas LA volume, LA contractile strain and LV peak a’ were higher, compared to young athletes. Multivariate regression analysis confirmed that age was predictive of peak e’, LA reservoir strain and LA conduit strain, independently of training variables. LA phasic strains were strongly associated with LV diastolic function.

Conclusions

Regardless of chronic sports practice, master athletes exhibited age-related changes in LA function closely coupled to LV diastolic properties, which led to LV filling shifts to late diastole.

Athlete Heart in Children and Young Athletes. Echocardiographic Findings in 331 Cases

The changes of the athlete's heart are not well defined and characterized in children. We aimed to describe the morphological changes of the heart related to sport in young athletes. We evaluated a group of 331 young athletes under 18 years (mean 11.9 ± 3.2) who practice tennis: 58 (16.52%), football: 118 (33.62%), basketball: 16 (4.56%), athletics: 40 (11.4%), and swimming: 99 (28.21%). Type of sport, years of practice, and duration of the training were collected. All children underwent echocardiography with the following M-mode parameters: left atrium diameter (LAD), interventricular septum (IVS), and left ventricle posterior Wall (LVPW), diastolic diameter of the left ventricle (LVDD), and right ventricle outflow tract (RVOT). The major finding of our study was that 20% of the children had a Z score > 2 for the IVS and that increased to 30% for the children playing tennis or swimming. Also, other changes like LA and RVOT dilatation were observed in about 10 and 14% of the cases, respectively. Taken together, these figures indicate that cardiac remodeling is frequent in children. Further studies are needed to establish consensus-based criteria of athlete's heart in young children.

The effects of activity, body weight, sex and age on echocardiographic values in English setter dogs

BACKGROUND

Breed-specific reference intervals improve echocardiographic interpretation and thereby reduce misdiagnoses, especially in athletic breeds.

OBJECTIVES

The objectives of the study were to examine transthoracic echocardiographic values in healthy adult English setter dogs and determine the effects of activity, body weight, sex and age on these values.

ANIMALS, MATERIALS AND METHODS

One hundred and one adult English setter dogs, recruited from local veterinary clinics and from the Norwegian English setter club, underwent routine transthoracic echocardiography. The population was stratified into two groups based on the reported level of activity. The effects of activity level, body weight, sex and age on echocardiographic variables were examined. Results were compared with published data from other breeds and from a pre-existing species-wide allometric model.

RESULTS

Of the 100 dogs between 19 months and 10 years of age included in the study, 72 were reported as very active and 28 as less active. Echocardiographic intervals were calculated for body size-independent echocardiographic variables. The upper limits of the intervals for left-atrial-to-aortic ratios and normalised left ventricular volumes exceeded those of various, previously published studies of other breeds. Normalised left ventricular dimensions exceeded published allometric 95^th percentile upper reference values in 13% of dogs in diastole and 32% of dogs in systole. More active dogs had larger cardiac dimensions than less active dogs; however, the activity level did not predict echocardiographic variables when included in a multiple regression model.

CONCLUSIONS

The study provides breed specific transthoracic echocardiographic values for English setter dogs, thereby contributing to improve diagnostic assessment of cardiac health in this breed.

Potential role of an athlete-focused echocardiogram in sports eligibility

Sudden cardiac death (SCD) of an athlete is a rare but tragic event and sport activity might play a trigger role in athletes with underlying structural or electrical heart diseases. Preparticipation screenings (PPs) have been conceived for the potential to prevent SCD in young athletes by early identification of cardiac diseases. The European Society of Cardiology protocol for PPs includes history collection, physical examination and baseline electrocardiogram, while further examinations are reserved to individuals with abnormalities at first-line evaluation. Nevertheless, transthoracic echocardiography has been hypothesized to have a primary role in the PPs. This review aims to describe how to approach an athlete-focused echocardiogram, highlighting what is crucial to focus on for the different diseases (cardiomyopathies, valvulopathies, congenital heart disease, myocarditis and pericarditis) and when is needed to pay attention to overlap diagnostic zone ("grey zone") with the athlete's heart. Once properly tested, focused echocardiography by sports medicine physicians may become standard practice in larger screening practices, potentially available during first-line evaluation.

Influencing Factors of Cardiac Adaptation in Adolescent Athletes

Endurance training-induced changes in left ventricular diastolic function and right ventricular parameters have been investigated extensively in adolescent athletes. Our aim was to examine the parameters for adolescent athletes (n=121, 15.1±1.6 years) compared to adult athletes and age-matched non-athletes. We explored the effects of influencing factors on the echocardiographic parameters. Significantly higher E/A (p<0.05) and e' values (p<0.001) were detected in adolescent athletes compared to age-matched non-athletes' and also adult athletes' parameters. Significantly lower structural and functional right ventricular parameters (p<0.05) were detected in adult athletes. In adolescent athletes significantly higher right ventricular diameters, tricuspid S wave, right ventricular end-diastolic and end-systolic area values (p<0.05) were found compared to the matching parameters of non-athletes. We found significantly higher corrected tricuspid annular plane systolic excursion values (p<0.001) in athletes compared to the non-athletes. Based on multivariate analysis lean body mass, body surface area, age and cumulative training time were proved as strong predictive factors of both left ventricular diastolic and right ventricular parameters. Supernormal left ventricular diastolic function and significantly higher right ventricular parameters are indicative of cardiac adaptation. Well-defined cut-off values should be applied to discriminate pathological conditions in the relation of the influencing factors.

When should cardiovascular prevention begin? The importance of antenatal, perinatal and primordial prevention

Cardiovascular diseases represent a major health problem, being one of the leading causes of morbidity and mortality worldwide. Therefore, in this scenario, cardiovascular prevention plays an essential role although it is difficult to establish when promoting and implementing preventive strategies. However, there is growing evidence that prevention should start even before birth, during pregnancy, aiming to avoid the onset of cardiovascular risk factors, since events that occur early in life have a great impact on the cardiovascular risk profile of an adult. The two pillars of this early preventive strategy are nutrition and physical exercise, together with prevention of cardio-metabolic diseases during pregnancy. This review attempts to gather the growing evidence of the benefits of antenatal, perinatal and primordial prevention, discussing also the possibility to reverse or to mitigate the cardiovascular profile developed in the initial stages of life. This could pave the way for future research, investigating the optimal time and duration of these preventing measures, their duration and maintenance in adulthood, and the most effective interventions according to the different age and guiding in the next years, the best clinical practice and the political strategies to cope with cardiovascular disease.

Impact of early sports specialisation on paediatric ECG

Athletes of pediatric age are growing in number. They are subject to a number of risks, among them sudden cardiac death (SCD). This study aimed to characterize the pediatric athlete population in Switzerland, to evaluate electrocardiographic findings based on the International Criteria for electrocardiography (ECG) Interpretation in Athletes, and to analyze the association between demographic data, sport type, and ECG changes. Retrospective, observational study of pediatric athletes (less than 18 years old) including medical history, physical examination, and a 12-lead resting ECG. The primary focus was on identification of normal, borderline, and abnormal ECG findings. The secondary observation was the relation between ECG and demographic, anthropometric, sport-related, and clinical data. The 891 athletes (mean 14.8 years, 35% girls) practiced 45 different sports on three different levels, representing all types of static and dynamic composition of the Classification of Sports by Mitchell. There were 75.4% of normal ECG findings, among them most commonly early repolarization, sinus bradycardia, and left ventricular hypertrophy; 4.3% had a borderline finding; 2.1% were abnormal and required further investigations, without SCD-related diagnosis. While the normal ECG findings were related to sex, age, and endurance sports, no such observation was found for borderline or abnormal criteria. Our results in an entirely pediatric population of athletes demonstrate that sex, age, and type of sports correlate with normal ECG findings. Abnormal ECG findings in pediatric athletes are rare. The International Criteria for ECG Interpretation in Athletes are appropriate for this age group.

Transcriptomic Bioinformatic Analyses of Atria Uncover Involvement of Pathways Related to Strain and Post-translational Modification of Collagen in Increased Atrial Fibrillation Vulnerability in Intensely Exercised Mice

Atrial Fibrillation (AF) is the most common supraventricular tachyarrhythmia that is typically associated with cardiovascular disease (CVD) and poor cardiovascular health. Paradoxically, endurance athletes are also at risk for AF. While it is well-established that persistent AF is associated with atrial fibrosis, hypertrophy and inflammation, intensely exercised mice showed similar adverse atrial changes and increased AF vulnerability, which required tumor necrosis factor (TNF) signaling, even though ventricular structure and function improved. To identify some of the molecular factors underlying the chamber-specific and TNF-dependent atrial changes induced by exercise, we performed transcriptome analyses of hearts from wild-type and TNF-knockout mice following exercise for 2 days, 2 or 6 weeks of exercise. Consistent with the central role of atrial stretch arising from elevated venous pressure in AF promotion, all 3 time points were associated with differential regulation of genes in atria linked to mechanosensing (focal adhesion kinase, integrins and cell-cell communications), extracellular matrix (ECM) and TNF pathways, with TNF appearing to play a permissive, rather than causal, role in gene changes. Importantly, mechanosensing/ECM genes were only enriched, along with tubulin- and hypertrophy-related genes after 2 days of exercise while being downregulated at 2 and 6 weeks, suggesting that early reactive strain-dependent remodeling with exercise yields to compensatory adjustments. Moreover, at the later time points, there was also downregulation of both collagen genes and genes involved in collagen turnover, a pattern mirroring aging-related fibrosis. By comparison, twofold fewer genes were differentially regulated in ventricles vs. atria, independently of TNF. Our findings reveal that exercise promotes TNF-dependent atrial transcriptome remodeling of ECM/mechanosensing pathways, consistent with increased preload and atrial stretch seen with exercise. We propose that similar preload-dependent mechanisms are responsible for atrial changes and AF in both CVD patients and athletes.

The determinants of positivisation of anterior T-wave inversion in children

BACKGROUND

Anterior T-wave inversion (aTWI) can be a common electrical sign in cardiomyopathies but also a benign feature regressing with age in healthy children. Unfortunately, little is known about the age of positivisation of aTWI and its determinants in children and longitudinal data are not available. The aim of this longitudinal study was to identify the age and determinants of positivisation of aTWI in healthy children.

METHODS

ATWI was observed in 331 healthy children. They were evaluated yearly until positivisation for a maximum period of 4 years. Positivisation of aTWI was observed in 312 children (94%). The weight, height/length and their respective percentiles at birth and at the time of positivisation of aTWI and weeks of gestation at birth were collected.

RESULTS

Positivisation of aTWI occurred at a mean age of 13.0±2.0 years. When aTWI became positive, the majority of children had a height between 51° and 75° or over the 75° percentile. At the multivariate logistic regression analysis height, weight, percentiles of height and weight at the time of positivisation were identified as the strongest independent predictors of the positivisation of aTWI. No correlation was found for prematurity and anthropometrics characteristics at birth.

CONCLUSIONS

ATWI is a common feature of pediatric ECG, usually regressing with age. Height, weight, percentiles of height and weight at the time of positivisation were identified as determinants of TWI positivisation. These simple anthropometric characteristics should be used in addition to chronological age in order to interpret aTWI in children.

Atrial size and sports. A great training for a greater left atrium: how much is too much?

Athlete's heart results from physiological adaptations to the increased demands of exercise, and left atrial (LA) enlargement (LAE) is a fundamental component. However, LAE occurs in certain pathological conditions and it might represent a diagnostic challenge in athletes. LA volume index (LAVi) by echo is a convenient diagnostic tool for LAE identification. We hypothesized that accumulated lifetime training thousand hours (LTH) would have a main role in LAE. Therefore, our aim was to assess the association between LTH, LAVi and LAE in athletes. Young and middle-aged males with different training levels were included and grouped as recreational (REa, n = 30), competitive (COa, n = 169) and elite (ELa, n = 80) athletes for LTH calculation and echo assessment. LA dimensions resulted greater in ELa when compared to other groups (p < 0.001). LAVi correlated stronger with LTH than with age (p < 0.001). Polynomial regression analysis showed a non-linear, almost triphasic, effect of cumulative training on LA size (p < 0.02). Multivariate logistic regression, including LTH, age, body surface area, systolic blood pressure and other explanatory variables to predict LAE, showed LTH as the sole significant factor [OR 1.45 (CI 1.1-1.92), p < 0.008]. ROC analysis found an optimal cut off point of 3.6 LTH for LAE identification (AUC = 0.84, p < 0.001. RR = 5.65, p < 0.001). We conclude that LAE associates with LTH more than with other clinical parameters, and with less impact at higher amounts of LTH. Lifetime training greater than 3600 hours increases the probability of finding LAE in athletes. Future research should provide more insights and implications of these findings.

The beneficial effect of low-intensity exercise on cardiac performance assessed by two-dimensional speckle tracking echocardiography

BACKGROUND

Regular physical activity is associated with cardiovascular health; however, intensive exercise can have harmful effects on the heart. Two-dimensional (2D) speckle tracking echocardiography (STE) is a well-established diagnostic tool to evaluate subclinical myocardial dysfunction and has been widely used in athletes in recent years. This study is designed to evaluate whether low-intensity exercise has beneficial effects on myocardial performance. We aimed to evaluate systolic and diastolic functions of myocardium derived from STE in sports practitioners in a low-intensity exercise training program.

METHOD

Eighty-four sports practitioners and eighty-two sedentary healthy controls were prospectively included in our study. In addition to standard 2D echocardiographic measurements, left ventricular (LV) global longitudinal strain (GLS), right ventricular (RV) GLS, RV-free wall strain (FWS), left atrium (LA) strain, and strain rate were analyzed.

RESULTS

Mean LV GLS was significantly higher in sports practitioners compared with sedentary population (-19.21 ± 2.61% vs -18.37 ± 2.75%, P = .044). RV GLS was significantly higher in sports practitioners than sedentary population (-21.82 ± 4.86% vs -20.04 ± 4.62%, P = .016). Longitudinal strain and strain rate of LA conduit phase were significantly higher in sports practitioners than sedentary participants (-23.60 ± 6.83% vs -20.20 ± 6.64%, P = .001; -2.45 ± 0.81 L/s vs -2.10 ± 0.89 L/s, P = .010; respectively). Also, LA conduit phase strain/contraction phase strain and conduit phase strain rate/contraction phase strain rate ratios were higher in sports practitioners (1.88 ± 0.93 vs 1.48 ± 0.63, P = .001; 1.42 ± 0.65 vs 1.16 ± 0.53, P = .005; respectively).

CONCLUSION

The findings in the current study suggest that regular low-intensity exercise may have a beneficial effect on both systolic and diastolic functions of the myocardium.

The adolescent athlete's heart; A miniature adult or grown-up child?

The systematic development of early age talent in sports academies has led to the professionalization of pediatric sport and the sports physician need to be aware of pediatric cardiological problems. Research into the medical cardiac care and assessment of the pediatric athlete are accumulating, but specific pediatric international guidelines are not available yet and reference data for ECG and echocardiography are incomplete, in particular for the age group <12 years of age. This article is an introduction to the physiological and diagnostics specifics of the pediatric athlete. The focus lies in the differences in presentation and diagnosis between pediatric and adult athletes for the most common pathologies. Reference data for electrical and structural adaptations to intensive exercise are sparse particularly in athletes aged below 12 years old. Training related changes include decrease of resting heart rate, increase of cardiac output, ventricular cavity size, and wall thickness. Cardiac hypertrophy is less pronounced in pediatric athletes, as HR mediated cardiac output increase to endurance exercise is the dominant mechanism in peripubertal children. As in adults, the most pronounced cardiovascular adaptations appear in classical endurance sports like rowing, triathlon, and swimming, but the specifics of pediatric ECG and echocardiographic changes need to be considered.

The use of cardiac imaging in the evaluation of athletes in the clinical practice: A survey by the Sports Cardiology and Exercise Section of the European Association of Preventive Cardiology and University of Siena, in collaboration with the European Association of Cardiovascular Imaging, the European Heart Rhythm Association and the ESC Working Group on Myocardial and Pericardial Diseases

AIMS

Pre-participation evaluation (PPE) is recommended to prevent sudden cardiac death in athletes. Although imaging is not advocated as a first-line screening tool, there is a growing interest in the use of echocardiography in PPE of athletes. This survey aimed to map the use of imaging in the setting of PPE and explore physician beliefs and potential barriers that may influence individual practices.

METHODS

An international survey of healthcare professionals was performed across ESC Member Countries. Percentages were reported based on the number of respondents per question.

RESULTS

In total, 603 individuals from 97 countries participated in the survey. Two-thirds (65%) of respondents use echocardiography always or often as part of PPE of competitive athletes and this practice is not influenced by the professional or amateur status of the athlete. The majority (81%) of respondents who use echocardiography as a first-line screening tool perform the first echocardiogram during adolescence or at the first clinical evaluation, and 72% repeat it at least once in the athletes' career, at 1-5 yearly intervals. In contrast, cardiac magnetic resonance is reserved as a second-line investigation of symptomatic athletes. The majority of the respondents did not report any barriers to echocardiography, while several barriers were identified for cardiac magnetic resonance.

CONCLUSIONS

Echocardiography is frequently used as a first-line screening tool of athletes. In the absence of scientific evidence, before such practice is recommended, large studies using echocardiography in the PPE setting are necessary.

The impact of demographic, anthropometric and athletic characteristics on left atrial size in athletes

The structural adaptations of the “athlete's heart” include left atrial (LA) enlargement. A literature search was performed based on PubMed listings up to November 2, 2019 using “athletes AND left atrium,” “athletes AND LA,” “sports AND left atrium,” “sports AND LA,” “exercise AND left atrium,” and “exercise AND LA” as the search terms. Eligible studies included those reporting the influence of demographic, anthropometric and athletic characteristics on LA size in athletes. A total of 58 studies were included in this review article. Although LA volume has been reported to be greater in males compared to females when indexed for body surface area (BSA), there was no difference between sexes. The positive association between LA size and age in athletes may reflect the increase in body size with maturation in nonadult athletes and the training age of endurance athletic activity in adult athletes. Caucasian and black athletes have been demonstrated to exhibit similar LA enlargement. The positive association of LA size with lean body mass (LBM) possibly accounts for the relationship of LA size with BSA. LA enlargement has been reported only in endurance‐trained, but not in strength‐trained athletes. LA size appears to increase with an increase in both the volume and intensity of endurance training. LA size correlates independently with the training age of endurance athletes. The athlete's characteristics that independently determine LA size include LBM, endurance training, and training age.

Left ventricular hypertrophy in athletes: How to differentiate between hypertensive heart disease and athlete’s heart

Athlete’s heart is typically accompanied by a remodelling of the cardiac chambers induced by exercise. However, although competitive athletes are commonly considered healthy, they can be affected by cardiac disorders characterised by an increase in left ventricular mass and wall thickness, such as hypertension. Unfortunately, training-induced increase in left ventricular mass, wall thickness, and atrial and ventricular dilatation observed in competitive athletes may mimic the pathological remodelling of pathological hypertrophy. As a consequence, distinguishing between athlete’s heart and hypertension can sometimes be challenging. The present review aimed to focus on the differential diagnosis between hypertensive heart disease and athlete’s heart, providing clinical information useful to distinguish between physiological and pathological remodelling.

Burden of premature atrial beats in middle-aged endurance athletes with and without lone atrial fibrillation versus sedentary controls

BACKGROUND

The burden of premature atrial beats (PABs) at 24-h electrocardiographic (ECG) monitoring correlates with the risk of atrial fibrillation. It is unknown whether prolonged and intense exercise increases the burden of PABs, thus contributing to the higher prevalence of atrial fibrillation observed in middle-aged athletes.

METHODS

We compared the burden of PABs at 24-h ECG monitoring off therapy in 134 healthy middle-aged (30-60-year-old) competitive athletes who had practised 9 (7-11) h of endurance sports for 8 (4-15) consecutive years, 134 age- and gender-matched healthy sedentary individuals, and 66 middle-aged patients (20 athletes and 46 non-athletes) with 'lone' paroxysmal atrial fibrillation.

RESULTS

More than 50 PABs/24 h or ≥1 run of ≥3 PABs were recorded in 23/134 (17%) healthy athletes and in 29/134 (22%) sedentary controls (p = 0.61). Healthy athletes with frequent or repetitive PABs were older (median 50 years vs. 43 years, p < 0.01) and had practised sport for a longer time (median 10 years vs. 6 years, p = 0.03). At multivariable analysis only age (odds ratio 1.11, 95% confidence interval 1.04-1.20, p < 0.01) remained an independent predictor of a higher burden of PABs. Also among patients with 'lone' paroxysmal atrial fibrillation, there was no difference in the prevalence of >50 PABs/24 h or ≥1 run of ≥3 PABs between athletes (40%) and controls (48%, p = 0.74).

CONCLUSIONS

Middle-aged endurance athletes, with or without paroxysmal atrial fibrillation, did not show a higher burden of PABs at 24-h ECG monitoring than sedentary controls. Age, but not intensity and duration of sports activity, predicted a higher burden of PABs among healthy athletes.

Cardiac remodeling after six weeks of high-intensity interval training to exhaustion in endurance-trained men

High-intensity interval training (HIIT) improves physical performance of endurance athletes, although studies examining its cardiovascular effects are sparse. We evaluated the impact of HIIT on blood pressure, heart rate, and cardiac cavities' size and function in endurance-trained adults. Seventeen endurance-trained men underwent 24-h ambulatory blood pressure monitoring and Doppler echocardiography at baseline and after 6 wk of HIIT. Participants were divided into 2 groups [85% maximal aerobic power (HIIT₈₅), n = 8 and 115% maximal aerobic power (HIIT₁₁₅), n = 9] to compare the impact of different HIIT intensities. Ambulatory blood pressure monitoring and cardiac chambers' size and function were similar between groups at baseline. HIIT reduced heart rate (55 ± 8 vs. 51 ± 7 beats/min; P = 0.003), systolic blood pressure (121 ± 11 vs. 118 ± 9 mmHg; P = 0.01), mean arterial pressure (90 ± 8 vs. 89 ± 6 mmHg; P = 0.03), and pulse pressure (52 ± 6 vs. 49 ± 5 mmHg; P = 0.01) irrespective of training intensity. Left atrium volumes increased after HIIT (maximal: 50 ± 14 vs. 54 ± 14 mL; P = 0.02; minimal: 15 ± 5 vs. 20 ± 8 mL; P = 0.01) in both groups. Right ventricle global longitudinal strain lowered after training in the HIIT₈₅ group only (20 ± 4 vs. 17 ± 3%, P = 0.04). In endurance-trained men, 6 wk of HIIT reduced systolic blood pressure and mean arterial pressure and increased left atrium volumes irrespective of training intensity, whereas submaximal HIIT deteriorated right ventricle systolic function.NEW & NOTEWORTHY The novel findings of this study are that 6 wk of high-intensity interval training increases left atrial volumes irrespective of training intensity (85 or 115% maximal aerobic power), whereas the submaximal training decreases right ventricular systolic function in endurance-trained men. These results may help identify the exercise threshold for potential toxicity of intense exercise training for at-risk individuals and ideal exercise training regimens conferring optimal cardiovascular protection and adapted endurance training for athletes.

Left atrial function in elite athletes: A meta-analysis of two-dimensional speckle tracking echocardiographic studies

BACKGROUND

We sought to investigate left atrial (LA) volume, function, and strain in elite athletes by a meta-analysis including echocardiographic studies that provided volumetric and strain analysis of LA phasic function.

METHODS

The OVID-MEDLINE, PubMed, and Cochrane CENTRAL databases were searched for English-language articles without time restriction up to February 2018 through focused and high sensitive search strategies. Studies were identified by crossing the following search terms: "athletes," "left atrial size," "left atrial volume," "atrial function," "atrial strain," "atrial strain rate," "echocardiography," "2D speckle echocardiography."

RESULTS

Meta-analysis included 403 athletes and 314 active but not trained healthy controls from 9 studies. Pooled data showed that average LA volume index was higher in athletes than in healthy controls (28.0 ± 1.0 vs 20.7 ± 0.8 mL/m2 , P < 0.001). Global LA longitudinal strain, showing LA reservoir function, was lower in the athletes than in healthy controls with borderline significance (37.0 ± 1.2 vs 38.3 ± 1.5%, P = 0.044). Late diastolic LA strain rate, resembling LA contractile function, was also lower in elite athletes than in control group (-1.56 ± 0.08 vs -1.74 ± 0.09 seconds -1, P = 0.007).

CONCLUSIONS

Our meta-analysis shows that LA volume is higher, while LA reservoir and contractile functions are impaired in elite athletes during active training compared to untrained controls. Whether these changes persist during deconditioning periods remains to be determined. These alterations may be related to the higher risk of arrhythmias, in particular atrial fibrillation, reported among middle/old aged athletes.

Comparison of echocardiographic linear dimensions for male and female child and adolescent athletes with published pediatric normative data

Background

Application of normative data for echocardiographic measurements to children practicing sports may lead to false positive findings. The aim of the study was to define the normative data of basic echocardiographic measurements for this group and to compare them to the previously published normative data for the pediatric population.

Methods

Parasternal long-axis 2D-guided echocardiographic measurements were obtained from a group of 791 child athletes (ages 5–18 years). According to the methodology presented previously by Pettersen et al. (2008), the regression equations for basic cardiac dimensions against body surface area were derived and individual Z-scores values were computed, using both Pettersen’s equations and newly derived ones.

Results

Z-scores computed based on Pettersen’s equations were found to differ significantly from those based on the new equations, for all the analyzed parameters (p<0.001). In agreement analysis, the most pronounced differences were found for the left atrium, interventricular septum and the left ventricular posterior wall. However, in most cases, the indications of abnormality were concordant (91.8%–97.6%); except for the left atrium, where there were 30.8% discordant results.

Conclusion

The study presents normative data for basic echocardiographic cardiac measurements for children of both sexes practicing varying sporting disciplines and compares them with general pediatric population. Mean values of cardiac dimensions are higher in young athletes, particularly in relation to the left atrium and left ventricular muscle thickness. In most cases, the upper limit of normality observed in the young athletes is confined within the upper limit of the general pediatric population.

Left ventricular function during exercise in trained pre-adolescent soccer players

It is unclear, what the underlying cardiovascular mechanisms are that give rise to the high level of aerobic fitness seen in youth soccer players. The aim of the study was to evaluate global and regional markers of systolic and diastolic function in a group of pre-adolescent soccer players during an incremental exercise test. Twenty-two, male soccer players (SP) from two professional soccer clubs (age: 12.0 ± 0.3 years) volunteered for the study. Fifteen recreationally active boys (CON), of similar age (age: 11.7 ± 0.2 years) were also recruited. All boys underwent a cycle ergometer test to exhaustion. Cardiac dimensions were determined using M-mode echocardiography. During submaximal and maximal exercise, continuous-wave Doppler ultrasound techniques were used to derive stroke volume (SVIndex). Tissue-Doppler imaging was used to quantify systolic (S'adj) and diastolic function (E; E'adj and E/E') at rest and both submaximal and maximal exercise intensities. Speckle tracking echocardiography was used to determine peak longitudinal ε at submaximal exercise intensities. SP demonstrated significantly (P ≤ 0.05) greater peak VO₂ values than CON (SP: 48.0 ± 5.0 vs CON: 40.1 ± 7.5 mL/kg/min). Allometrically scaled to body surface area left ventricular end-diastolic volume (LVEDV) was larger (P ≤ 0.05) in the SP (51.3 ± 9.0) compared to CON (44.6 ± 5.8 mL·BSA^1.5 ). At the same relative, submaximal exercise intensities, the SP demonstrated greater SVIndex, cardiac output (QIndex), and E. No differences were noted for peak longitudinal ε during submaximal exercise. Factors that augment pre-load and LV volume appear to determine the superior aerobic fitness seen in the soccer players.

Reference values of left heart echocardiographic dimensions and mass in male peri-pubertal athletes

Background

Several articles have proposed reference values in healthy paediatric subjects, but none of them has evaluated a large population of healthy trained adolescents.

Design

The study purpose was to establish normal echocardiographic measurements of left heart (aortic root, left atrium and left ventricular dimensions and mass) in relation to age, weight, height, body mass index, body surface area and training hours in this specific population.

Methods

We retrospectively evaluated 2151 consecutive, healthy, peri-pubertal athletes (100% male, mean age 12.4 ± 1.4 years, range 8–18) referred to a single centre for pre-participation screening. All participants were young soccer athletes who trained for a mean of 7.2 ± 1.1 h per week.

Results

Left ventricular internal diameters, wall thickness, left ventricular mass, aortic root and left atrium diameters were significantly correlated to age, body surface area, height and weight ( p < 0.01). Age, height, weight and body surface area were found associated with chamber size, while body mass index and training hours were not. Inclusion of both age and body size parameters in the statistical models resulted in improved overall explained variance for diameters and left ventricular mass.

Conclusion

Equations, mean values and percentile charts for the different age groups may be useful as reference data in efficiently assessing left ventricular parameters in young athletes.

Cardiac Magnetic Resonance Assessment of the Structural and Functional Cardiac Adaptations to Soccer Training in School-Aged Male Children

Physical training is associated with changes in cardiac morphology called the "athlete's heart", which has not been sufficiently studied in children. The aim of the study was to analyze cardiac adaptation to exercise in pre-adolescent soccer players. Thirty-six soccer players (mean age 10.1 ± 1.4 years) and 24 non-athlete male controls (10.4 ± 1.7 years) underwent cardiac magnetic resonance. Measurements of myocardial mass, end-diastolic and end-systolic volume, stroke volume and ejection fraction for left and right ventricle (LV, RV) were performed. Additionally, left and right atrial (LA, RA) areas and volumes were analysed. Relative wall thickness (RWT) was calculated to describe the pattern of cardiac remodeling. Interventricular wall thickness and LV mass were significantly higher in athletes, but remained within the reference (6.9 ± 0.8 vs. 6.2 ± 0.9 mm/√m², p = 0.003 and 57.1 ± 7.4 vs. 50.0 ± 7.1 g/m², p = 0.0006, respectively) with no changes in LV size and function between groups. The RWT tended to be higher among athletes (p = 0.09) indicating LV concentric remodeling geometry. Soccer players had significantly larger RV size (p < 0.04) with similar function and mass. Also, the LA volume (p = 0.01), LA area (p = 0.03) and LA diameter (p = 0.009) were significantly greater in players than in controls. Cardiac adaptations in pre-adolescent soccer players are characterized by an increased LV mass without any changes in LV size and systolic function, which is typical of resistance training with tendency to concentric remodeling. This is accompanied by increase of LA and RV size. It should be taken into account during annual pre-participation evaluation.

Cardiac damage in athlete's heart: When the "supernormal" heart fails!

Intense exercise may cause heart remodeling to compensate increases in blood pressure or volume by increasing muscle mass. Cardiac changes do not involve only the left ventricle, but all heart chambers. Physiological cardiac modeling in athletes is associated with normal or enhanced cardiac function, but recent studies have documented decrements in left ventricular function during intense exercise and the release of cardiac markers of necrosis in athlete's blood of uncertain significance. Furthermore, cardiac remodeling may predispose athletes to heart disease and result in electrical remodeling, responsible for arrhythmias. Athlete's heart is a physiological condition and does not require a specific treatment. In some conditions, it is important to differentiate the physiological adaptations from pathological conditions, such as hypertrophic cardiomyopathy, arrhythmogenic dysplasia of the right ventricle, and non-compaction myocardium, for the greater risk of sudden cardiac death of these conditions. Moreover, some drugs and performance-enhancing drugs can cause structural alterations and arrhythmias, therefore, their use should be excluded.

Electrocardiographic Changes Induced by Endurance Training and Pubertal Development in Male Children

Training-induced electrocardiographic changes are common in adult athletes. However, a few data are available on electrocardiogram (ECG) in preadolescent athletes and little is known about the potential changes induced by training on 12-lead electrocardiogram (ECG) at rest. Twelve-lead ECGs at rest and complete echocardiographic examinations were performed in 94 children (57 endurance athletes, 37 sedentary controls; mean age 10.8 ± 0.2 and 10.2 ± 0.2 years, respectively) at baseline and after 5 months of growth and training in athletes and of natural growth in controls. At baseline, athletes had lower heart rate at rest compared with controls (p = 0.046) and a further decrease was observed after training (p <0.0001). An incomplete right bundle branch block was found in 19% of athletes and 15% of controls (p = 0.69) with no changes after training. Although none of the athletes showed negative T waves from V1 to V3, 6% of controls at baseline had T-wave inversion V1 to V3 with a decrease to 3% after 5 months (p = 0.16). The early repolarization pattern did not differ between athletes and controls and was correlated with Tanner's scale score in the overall population both at first and second evaluation (R = 0.30, R = 0.27, p = 0.005, p = 0.012, respectively). No correlations were found between ECG and echocardiographic data. In conclusion, 12-lead ECG at rest is not substantially affected by training in children, despite a physiological increase in cavity size. Thus, in preadolescent athletes, 12-lead ECG at rest does not reflect exercise-induced morphologic remodeling and seems to be influenced more by sexual maturation than by training.