The athlete's heart: allometric considerations on published papers and relation to cardiovascular variables

To evaluate the morphology of the "athlete's heart", left ventricular (LV) wall thickness (WT) and end-diastolic internal diameter (LVIDd) at rest were addressed in publications on skiers, rowers, swimmers, cyclists, runners, weightlifters (n = 927), and untrained controls (n = 173) and related to the acute and maximal cardiovascular response to their respective disciplines. Dimensions of the heart at rest and functional variables established during the various sport disciplines were scaled to body weight for comparison among athletes independent of body mass. The two measures of LV were related (r = 0.8; P = 0.04) across athletic disciplines. With allometric scaling to body weight, LVIDd was similar between weightlifters and controls but 7%-15% larger in the other athletic groups, while WT was 9%-24% enlarged in all athletes. The LVIDd was related to stroke volume, oxygen pulse, maximal oxygen uptake, cardiac output, and blood volume (r =  ~ 0.9, P < 0.05), while there was no relationship between WT and these variables (P > 0.05). In conclusion, while cardiac enlargement is, in part, essential for the generation of the cardiac output and thus stroke volume needed for competitive endurance exercise, an enlarged WT seems important for the development of the wall tension required for establishing normal arterial pressure in the enlarged LVIDd.

Unlocking the potential of artificial intelligence in sports cardiology: does it have a role in evaluating athlete's heart?

The integration of artificial intelligence (AI) technologies is evolving in different fields of cardiology and in particular in sports cardiology. Artificial intelligence offers significant opportunities to enhance risk assessment, diagnosis, treatment planning, and monitoring of athletes. This article explores the application of AI in various aspects of sports cardiology, including imaging techniques, genetic testing, and wearable devices. The use of machine learning and deep neural networks enables improved analysis and interpretation of complex datasets. However, ethical and legal dilemmas must be addressed, including informed consent, algorithmic fairness, data privacy, and intellectual property issues. The integration of AI technologies should complement the expertise of physicians, allowing for a balanced approach that optimizes patient care and outcomes. Ongoing research and collaborations are vital to harness the full potential of AI in sports cardiology and advance our management of cardiovascular health in athletes.

The Fragmented QRS Complex in Lead V1: Time for an Update of the Athlete's ECG?

Differentiating between ECG patterns related to athletes' heart remodeling and pathological findings is a challenge in sports cardiology. As the significance of fragmented complex in athletes remains uncertain, this study aimed to assess the presence of fragmented QRS in lead V1 (fQRSV1) among young athletes and its association with heart adaptations and arrhythmias. Young athletes referred for annual pre-participation screening receiving a maximal exercise testing and transthoracic echocardiography from January 2015 to March 2021 were included. The study included 684 young athletes. The prevalence of fQRSV1 was 33%. Subjects with fQRSV1 had higher exercise capacity and indexes of right ventricular function and remodeling. Among highly trained athletes, the fQRSV1 group demonstrated also increased left ventricular wall thickness. No significant association existed between fQRSV1 and exercise-induced arrhythmias, even in highly trained athletes. The high prevalence of fQRSV1 in young athletes is associated with training-induced heart adaptations but not exercise-induced ventricular arrhythmias.

Cardiac imaging in athlete's heart: current status and future prospects

BACKGROUND

Physical activity contributes to changes in cardiac morphology, which are known as "athlete's heart". Therefore, these modifications can be characterized using different imaging modalities such as echocardiography, including Doppler (flow Doppler and Doppler myocardial imaging) and speckle-tracking, along with cardiac magnetic resonance, and cardiac computed tomography.

MAIN TEXT

Echocardiography is the most common method for assessing cardiac structure and function in athletes due to its availability, repeatability, versatility, and low cost. It allows the measurement of parameters like left ventricular wall thickness, cavity dimensions, and mass. Left ventricular myocardial strain can be measured by tissue Doppler (using the pulse wave Doppler principle) or speckle tracking echocardiography (using the two-dimensional grayscale B-mode images), which provide information on the deformation of the myocardium. Cardiac magnetic resonance provides a comprehensive evaluation of cardiac morphology and function with superior accuracy compared to echocardiography. With the addition of contrast agents, myocardial state can be characterized. Thus, it is particularly effective in differentiating an athlete's heart from pathological conditions, however, is less accessible and more expensive compared to other techniques. Coronary computed tomography is used to assess coronary artery anatomy and identify anomalies or diseases, but its use is limited due to radiation exposure and cost, making it less suitable for young athletes. A novel approach, hemodynamic forces analysis, uses feature tracking to quantify intraventricular pressure gradients responsible for blood flow. Hemodynamic forces analysis has the potential for studying blood flow within the heart and assessing cardiac function.

CONCLUSIONS

In conclusion, each diagnostic technique has its own advantages and limitations for assessing cardiac adaptations in athletes. Examining and comparing the cardiac adaptations resulting from physical activity with the structural cardiac changes identified through different diagnostic modalities is a pivotal focus in the field of sports medicine.

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.

Seasonal variation of cardiac structure and function in the elite rugby football league athlete

BACKGROUND

Pre-participation cardiac screening (PCS) of "Super-League" rugby football league (RFL) athletes is mandatory but may be completed at any time point. The aim of this study was to assess cardiac electrical, structural and functional variation across the competitive season.

METHODS

Elite, male, RFL athletes from a single Super-League club underwent cardiac evaluation using electrocardiography (ECG), 2D echocardiography and speckle tracking echocardiography (STE) at four time points across the RFL season; (1) End pre-season (ENDPRE), (2) mid-season (MIDCOMP), (3) end-season (ENDCOMP) and (4) End off-season (ENDOFF). Training loads for each time point were also determined. One-way ANOVA with post-hoc Bonferroni were used for statistical analyses.

RESULTS

Total workload undertaken by athletes was lower at both MIDCOMP and ENDCOMP compared to ENDPRE (P < 0.001). ECG patterns were normal with training-related changes that were largely consistent across assessments. Structural data did not vary across assessment points. Standard functional data was not different across assessment points but apical rotation and twist were higher at ENDPRE (9.83˚ and 16.55˚, respectively compared to all other time points (MIDCOMP, 6.13˚ and 12.62˚; ENDCOMP, 5.84˚ and 12.12˚; ENDOFF 6.60˚ and 12.35˚).

CONCLUSIONS

Despite some seasonal variation in training load, the athletes' ECG and cardiac structure were stable across a competitive season. Seasonal variation in left ventricular (LV) apical rotation and twist, associated with higher training loads, should be noted in the context of PCS.

Normative values of non-invasively assessed RV function and pulmonary circulation coupling for pre-participation screening derived from 497 male elite athletes

BACKGROUND

Reference values for right ventricular function and pulmonary circulation coupling were recently established for the general population. However, normative values for elite athletes are missing, even though exercise-related right ventricular enlargement is frequent in competitive athletes.

METHODS

We examined 497 healthy male elite athletes (age 26.1 ± 5.2 years) of mixed sports with a standardized transthoracic echocardiographic examination. Tricuspid annular plane excursion (TAPSE) and systolic pulmonary artery pressure (SPAP) were measured. Pulmonary circulation coupling was calculated as TAPSE/SPAP ratio. Two age groups were defined (18-29 years and 30-39 years) and associations of clinical parameters with the TAPSE/SPAP ratio were determined and compared for each group.

RESULTS

Athletes aged 18-29 (n = 349, 23.8 ± 3.5 years) displayed a significantly lower TAPSE/SPAP ratio (1.23 ± 0.3 vs. 1.31 ± 0.33 mm/mmHg, p = 0.039), TAPSE/SPAP to body surface area (BSA) ratio (0.56 ± 0.14 vs. 0.6 ± 0.16 mm*m2/mmHg, p = 0.017), diastolic blood pressure (75.6 ± 7.9 vs. 78.8 ± 10.7 mmHg, p < 0.001), septal wall thickness (10.2 ± 1.1 vs. 10.7 ± 1.1 mm, p = 0.013) and left atrial volume index (27.5 ± 4.5 vs. 30.8 ± 4.1 ml/m2, p < 0.001), but a higher SPAP (24.2 ± 4.5 vs. 23.2 ± 4.4 mmHg, p = 0.035) compared to athletes aged 30-39 (n = 148, 33.1 ± 3.4 years). TAPSE was not different between the age groups. The TAPSE/SPAP ratio was positively correlated with left ventricular stroke volume (r = 0.133, p = 0.018) and training amount per week (r = 0.154, p = 0.001) and negatively correlated with E/E' lat. (r = -0.152, p = 0.005).

CONCLUSION

The reference values for pulmonary circulation coupling determined in this study could be used to interpret and distinguish physiological from pathological cardiac remodeling in male elite athletes.

Long-Term Training Increases Atrial Fibrillation Sustainability in Standardbred Racehorses

Atrial fibrillation (AF) is more prevalent in athletes, and currently, the mechanisms are not fully understood. Atrial fibrillation inducibility and stability was investigated in trained and untrained Standardbred racehorses. The horses underwent echocardiography for evaluation of atrial size. High-density mapping during AF was performed, and the presence of structural remodeling, as well as the expression of inflammatory and pro-inflammatory markers in the atria, was studied. Atrial fibrillation sustained significantly longer after tachypacing in the trained horses, whereas no difference in AF inducibility was found. The untrained horses displayed a significant difference in the AF complexity when comparing right and left atria, whereas such difference was not observed in the trained animals. No evidence of increased structural remodeling or inflammation could be identified. Left atrial dimensions were not significantly increased. The increased AF sustainability in trained horses was not related to fibrosis or inflammation as seen in other animal exercise models.

Lifelong endurance exercise and its relation with coronary atherosclerosis

AIMS

The impact of long-term endurance sport participation (on top of a healthy lifestyle) on coronary atherosclerosis and acute cardiac events remains controversial.

METHODS AND RESULTS

The Master@Heart study is a well-balanced prospective observational cohort study. Overall, 191 lifelong master endurance athletes, 191 late-onset athletes (endurance sports initiation after 30 years of age), and 176 healthy non-athletes, all male with a low cardiovascular risk profile, were included. Peak oxygen uptake quantified fitness. The primary endpoint was the prevalence of coronary plaques (calcified, mixed, and non-calcified) on computed tomography coronary angiography. Analyses were corrected for multiple cardiovascular risk factors. The median age was 55 (50-60) years in all groups. Lifelong and late-onset athletes had higher peak oxygen uptake than non-athletes [159 (143-177) vs. 155 (138-169) vs. 122 (108-138) % predicted]. Lifelong endurance sports was associated with having ≥1 coronary plaque [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.17-2.94], ≥ 1 proximal plaque (OR 1.96, 95% CI 1.24-3.11), ≥ 1 calcified plaques (OR 1.58, 95% CI 1.01-2.49), ≥ 1 calcified proximal plaque (OR 2.07, 95% CI 1.28-3.35), ≥ 1 non-calcified plaque (OR 1.95, 95% CI 1.12-3.40), ≥ 1 non-calcified proximal plaque (OR 2.80, 95% CI 1.39-5.65), and ≥1 mixed plaque (OR 1.78, 95% CI 1.06-2.99) as compared to a healthy non-athletic lifestyle.

CONCLUSION

Lifelong endurance sport participation is not associated with a more favourable coronary plaque composition compared to a healthy lifestyle. Lifelong endurance athletes had more coronary plaques, including more non-calcified plaques in proximal segments, than fit and healthy individuals with a similarly low cardiovascular risk profile. Longitudinal research is needed to reconcile these findings with the risk of cardiovascular events at the higher end of the endurance exercise spectrum.

Three-dimensional echocardiography of the athlete's heart: a comparison with cardiac magnetic resonance imaging

Three-dimensional echocardiography (3DE) is the most accurate cardiac ultrasound technique to assess cardiac structure. 3DE has shown close correlation with cardiac magnetic resonance imaging (CMR) in various populations. There is limited data on the accuracy of 3DE in athletes and its value in detecting alterations during follow-up. Indexed left and right ventricular end-diastolic volume (LVEDVi, RVEDVi), end-systolic volume, ejection fraction (LVEF, RVEF) and left ventricular mass (LVMi) were assessed by 3DE and CMR in two-hundred and one competitive endurance athletes (79% male) from the Pro@Heart trial. Sixty-four athletes were assessed at 2 year follow-up. Linear regression and Bland-Altman analyses compared 3DE and CMR at baseline and follow-up. Interquartile analysis evaluated the agreement as cardiac volumes and mass increase. 3DE showed strong correlation with CMR (LVEDVi r = 0.91, LVEF r = 0.85, LVMi r = 0.84, RVEDVi r = 0.84, RVEF r = 0.86 p < 0.001). At follow up, the percentage change by 3DE and CMR were similar (∆LVEDVi r = 0.96 bias - 0.3%, ∆LVEF r = 0.94, bias 0.7%, ∆LVMi r = 0.94 bias 0.8%, ∆RVESVi r = 0.93, bias 1.2%, ∆RVEF r = 0.87 bias 0.4%). 3DE underestimated volumes (LVEDVi bias - 18.5 mL/m², RVEDVi bias - 25.5 mL/m²) and the degree of underestimation increased with larger dimensions (Q1vsQ4 LVEDVi relative bias - 14.5 versus - 17.4%, p = 0.016; Q1vsQ4 RVEDVi relative bias - 17 versus - 21.9%, p = 0.005). Measurements of cardiac volumes, mass and function by 3DE correlate well with CMR and 3DE accurately detects changes over time. 3DE underestimates volumes and the relative bias increases with larger cardiac size.

[The athlete's ECG : What is normal or abnormal?]

BACKGROUND

The electrocardiogram (ECG) has become a mobile and cost-effective routine assessment tool to risk stratify leisure-time and professional athletes during preparticipation screening. A central goal is the reduction of sudden cardiac death in sports through early recognition of the most prevalent underlying cardiac pathologies, e.g., hereditary cardiomyopathies or primary arrhythmias.

METHODS

Continuous evolution of the first ECG criteria for athletes, presented in 2010 by the European Society of Cardiology (ESC), has helped to improve the specificity of the criteria to both detect cardiac pathologies in early stages and differentiate from physiologic adaptation of the athlete's heart. Thus, the risk of false-positive findings and erroneous stigmatizations of athletes has been successfully reduced.

CONCLUSION

This review article intends to trace back the changes of the ECG criteria in the light of a growing body of scientific evidence over the last 15 years, to present the key messages of the current International ECG criteria from 2017 and to identify some of the remaining challenges that wait to be answered by physicians in the field of sports medicine and sports cardiology.

Echocardiographic Evaluation of the Athlete's Heart: Focused Review and Update

PURPOSE OF REVIEW

The athlete's heart exhibits unique structural and functional adaptations in the setting of strenuous and repetitive athletic training which may be similarly found in pathologic states. The purpose of this review is to highlight the morphologic and functional changes associated with the athlete's heart, with a focus upon the insights that echocardiography provides into exercise-induced cardiac remodeling.

RECENT FINDINGS

Recent studies are aiming to investigate the long-term effects and clinical consequences of an athlete's heart. The "gray-zone" continues to pose a clinical challenge and may indicate scenarios where additional imaging modalities, or longitudinal follow-up, provide a definitive answer. Echocardiography is likely to remain the first-line imaging modality for the cardiac evaluation of elite athletes. Multimodality imaging combined with outcome and long-term follow-up studies both during training and after retirement in both men and women may help further clarify the remaining mysteries in the coming years.

Cardiac screening prior to return to play after SARS-CoV-2 infection: focus on the child and adolescent athlete: A Clinical Consensus Statement of the Task Force for Childhood Health of the European Association of Preventive Cardiology

Cardiac sequelae after COVID-19 have been described in athletes, prompting the need to establish a return-to-play (RTP) protocol to guarantee a safe return to sports practice. Sports participation is strongly associated with multiple short- and long-term health benefits in children and adolescents and plays a crucial role in counteracting the psychological and physical effects of the current pandemic. Therefore, RTP protocols should be balanced to promote safe sports practice, particularly after an asymptomatic SARS-CoV-2 infection that represents the common manifestation in children. The present consensus document aims to summarize the current evidence on the cardiac sequelae of COVID-19 in children and young athletes, providing key messages for conducting the RTP protocol in paediatric athletes to promote a safe sports practice during the COVID-19 era.

Updated Blood Pressure Guidelines: Implications for Athletes

PURPOSE OF REVIEW

To review the prevalence, short- and long-term impact of exercise on blood pressure, and the evaluation and treatment of hypertension in competitive athletes.

RECENT FINDINGS

Due, in part, to inconsistencies in measurement and the definitions used, the true prevalence of hypertension is unknown as reports range from 0 to 83%. With recent changes in the blood pressure guidelines, the proportion of athletes that meet criteria for elevated blood pressure or stage 1 hypertension has increased dramatically with over one-third of collegiate and professional athletes meeting criteria for hypertension. Data consistently show that American-style football players, particularly linemen, display the highest rates of hypertension. These athletes typically have a larger body mass index, higher body fat percentage, and weight gain in serial follow-up. Many athletes with hypertension have traditional risk factors, and, to date, there is no evidence of a causal relationship between long-term sport participation and increased risk of developing hypertension. Many more athletes now meet criteria for hypertension, given the updated blood pressure guidelines. This should be taken as an opportunity for early intervention, as athletes are not immune to the development of cardiovascular risk factors and disease.

Differentiating Physiology from Pathology: The Gray Zones of the Athlete's Heart

Routine vigorous exercise can lead to electrical, structural, and functional adaptations that can enhance exercise performance. There are several factors that determine the type and magnitude of exercise-induced cardiac remodeling (EICR) in trained athletes. In some athletes with pronounced cardiac remodeling, there can be an overlap in morphologic features with mild forms of cardiomyopathy creating gray zone scenarios whereby distinguishing health from disease can be difficult. An integrated clinical approach that factors athlete-specific characteristics (sex, size, sport, ethnicity, and training history) and findings from multimodality imaging are essential to help make this distinction.

Exercise Stress Testing in Athletes

Exercise stress testing (EST) is indicated for diagnostic and prognostic purposes in the general population. In athletes, stress tests can also be useful to inform the risk of high-intensity training and competition, to assess athletic conditioning, and to refine training regimens. Many specific indications for EST are unique to athletes. Treadmill and cycle ergometer protocols each have their strengths and disadvantages; extensive protocol customization may be necessary to answer the clinical question at hand. A comprehensive understanding of the available tools for exercise testing, their strengths, and their limitations is crucial to providing cardiovascular care to athletic individuals.

Role of cardiac magnetic resonance imaging in troponinemia syndromes

Cardiac magnetic resonance imaging (MRI) is an evolving technology, proving to be a highly accurate tool for quantitative assessment. Most recently, it has been increasingly used in the diagnostic and prognostic evaluation of conditions involving an elevation in troponin or troponinemia. Although an elevation in troponin is a nonspecific marker of myocardial tissue damage, it is a frequently ordered investigation leaving many patients without a specific diagnosis. Fortunately, the advent of newer cardiac MRI protocols can provide additional information. In this review, we discuss several conditions associated with an elevation in troponin such as myocardial infarction, myocarditis, Takotsubo cardiomyopathy, coronavirus disease 2019 related cardiac dysfunction and athlete’s heart syndrome.

Difference in cardiac remodeling between female athletes and pregnant women: a case control study

Objectives

The aim of this study was to detect possible differences in reversible cardiac remodeling occurring in sport training and twin pregnancy. Background: cardiac remodeling occurs in athletes and pregnant women due to training and fetal requirements, respectively. These changes could be apparently similar.

Methods

21 female elite athletes (23.2 ± 5.3 years), 25 women with twin pregnancies (35.4 ± 5.7 years) and 25 healthy competitive female athletes (controls), age-matched with pregnant women (34.9 ± 7.9 years), were enrolled. This latter group was included to minimize the effect of age on cardiac remodeling. All women evaluated through anamnestic collection, physical examination, 12 leads ECG, standard echocardiogram and strain analysis. Sphericity (SI) and apical conicity (ACI) indexes were also calculated.

Results

Pregnant women showed higher LA dimension (p < 0.001) compared to both groups of athletes. LV e RV GLS were significantly different in pregnant women compared to female athletes (p = 0.02 and 0.03, respectively). RV GLS was also different between pregnant women and controls (p = 0.02). Pregnant women showed significantly higher S′ wave compared to female athletes (p = 0.02) but not controls. Parameters of diastolic function were significantly higher in athletes (p = 0.08 for IVRT and p < 0.001 for E/A,). SI was lower in athletes in both diastole (p = 0.01) and systole (p < 0.001), while ACIs was lower in pregnant women (p = 0.04).

Conclusions

Cardiac remodeling of athletes and pregnant women could be similar at first sight but different in LV shape and in GLS, highlighting a profound difference in longitudinal deformation between athletes and pregnant women. This difference seems not to be related with age. These findings suggest that an initial maternal cardiovascular maladaptation could occur in the third trimester of twin pregnancies.

Exercise-induced alterations of myocardial sarcomere dynamics are associated with hypophosphorylation of cardiac troponin I

Although the knowledge of sports cardiology advanced significantly in the recent years, the molecular mechanisms by which exercise training augments cardiac performance is poorly understood. Here we aimed at determining left ventricular (LV) myocardial sarcomeric protein modifications in a rat model of exercise training and detraining. Young male Wistar rats were divided into exercised (Ex) and control (Co) groups. Trained rats swam 200 min/day for 12 weeks. Detrained (DEx) and control (DCo) rats remained sedentary for 8 weeks after completion of the 12-week-long protocol. Ca²⁺-regulated active force production (F_{a⁢c⁢t⁢i⁢v⁢e}), its Ca²⁺-sensitivity (pCa₅₀) and Ca²⁺-independent passive tension (F_{p⁢a⁢s⁢s⁢i⁢v⁢e}) were determined in isolated permeabilized cardiomyocytes and phosphorylation levels of sarcomeric proteins were assayed by biochemical methods. Means of maximal Ca²⁺-activated isometric force (F_m⁢a⁢x) and pCa50 values were higher (p < 0.05) in the Ex group (28.0 ± 1.4 kN/m² and 5.91 ± 0.03, respectively, mean ± SEM) than those in the Co group (15.8 ± 0.8 kN/m² and 5.81 ± 0.03, respectively). F_{p⁢a⁢s⁢s⁢i⁢v⁢e} did not differ between these two groups. The level of cardiac troponin I (cTnI) phosphorylation decreased upon exercise (from 1.00 ± 0.02 to 0.66 ± 0.06, p < 0.05; in relative units). Site specific phosphorylation assays revealed cTnI hypophosphorylations at the protein kinase A (PKA)-specific Ser-22/23 sites and at the protein kinase C (PKC)-specific Thr-143 site. Mechanical and biochemical parameters of the DEx and DCo groups did not differ from each other following the detraining period. Exercise-induced hypertrophy is associated with reversible increases in Ca²⁺-dependent force production and its Ca²⁺-sensitivity in LV cardiomyocytes, which can be associated with changes in cTnI phosphorylation.

COVID-19: the Risk to Athletes

Purpose of Review

The COVID-19 pandemic has had a profound impact on athletics, and the question of safely resuming competitive sports at all levels has been a source of significant debate. Concerns regarding myocarditis and the risk of arrhythmias and sudden death in athletes have prompted heightened attention to the role of cardiovascular screening. In this review, we aim to comprehensively outline the cardiovascular manifestations associated with COVID-19 infection, to discuss screening, diagnosis, and treatment strategies, and to evaluate the current literature on the risk to athletes and recommendations regarding return-to-play.

Recent Findings

COVID-19 is known to cause myocarditis, with presentations ranging from subclinical current or prior infection detected on cardiac MRI imaging, to fulminant heart failure and shock. While initial data early in the pandemic suggested that the risk of myocarditis could be significant even in patients with nonsevere COVID-19 infection, recent studies suggest a very low prevalence of clinically significant disease in young athletes.

Summary

While COVID-19 can have significant cardiovascular manifestations, recent data demonstrate that a screening approach guided by severity of COVID-19 infection and cardiovascular symptoms allows the majority of athletes to safely return to play in a timely manner. We must continue to tailor our approach to screening athletes as knowledge grows, and further research on the longitudinal cardiovascular effects of COVID-19 is needed.

Advanced cardiac imaging in athlete's heart: unravelling the grey zone between physiologic adaptation and pathology

Over the last decades, interest toward athlete’s heart has progressively increased, leading to improve the knowledge on exercise-induced heart modifications. Sport may act as a trigger for life-threatening arrhythmias in patients with structural or electrical abnormalities, hence requiring to improve the diagnostic capability to differentiate physiological from pathological remodeling. Pathological alterations are often subtle at the initial stages; therefore, the challenge is to promptly identify athletes at risk of sudden cardiac death during the pre-participation screening protocols. Advanced imaging modalities such as coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) can non-invasively depict coronary vessels and provide a deep morpho-functional and structural characterization of the myocardium, in order to rule out pathological life threatening alterations, which may overlap with athletes’ heart remodeling. The purpose of the present narrative review is to provide an overview of most frequent diagnostic challenges, defining the boundaries between athlete's heart remodeling and pathological structural alteration with a focus on the role and importance of CCTA and CMR.

Benefits and limitations of electrocardiographic and echocardiographic screening in top level endurance athletes

The study was designed to assess the usefulness of routine electrocardiography (ECG) as well as transthoracic echocardiography (TTE) in screening top level endurance athletes. An additional goal was to attempt to identify factors determining occurrence of adaptive and abnormal changes in ECG and TTE. The retrospective analysis included basic medical data, ECG and TTE results of 262 athletes (123 rowers, 32 canoeists and 107 cyclists), members of the Polish National Team. The athletes were divided into two age groups: young (≤ 18 years; n = 177) and elite (> 18 years; n = 85). ECG and TTE measurements were analysed according to the International Recommendations from 2017 and 2015, respectively. Adaptive ECG changes were found in 165 (63%) athletes. Abnormal ECG changes were identified in 10 (3.8%) athletes. 98% of athletes exceeded TTE norms for the general population and 26% exceeded norms for athletes. The occurrence of both adaptive ECG findings and abnormalities in the TTE (in norms for athletes) was strongly associated with the years of training, hours of training per week and the age of the athlete. Male gender and the years of training were independent predictors of the ECG and TTE findings. Abnormal ECG changes were not related to the time of sport. Among 10 athletes with ECG changes, only 3 had changes in TTE and no relationship was found between abnormal finding in ECG and TTE (p = 0.45). ECG and TTE screening complement each other in identifying endurance athletes requiring treatment or verification. Unlike abnormal ECG changes, adaptive ECG changes and TTE abnormalities are strongly related to the training duration, which reflects physiological adaptation of the heart to physical exertion in high endurance athletes.

The heart of the ageing endurance athlete: the role of chronic coronary stress

Moderate physical exercise is associated with an irrefutable reduction in cardiac morbidity and mortality. The current guidelines recommend at least 150 min of moderate exercise or 75 min of vigorous exercise per week. Endurance athletes perform exercise at a level that is 10- to 20-fold greater than these recommendations. These athletes reveal several structural and functional cardiac adaptations including increased cardiac size, enhanced ventricular filling, and augmentation of stroke volume even at the highest heart rates. The long-term effects of endurance exercise on the heart are unknown. Endurance exercise is associated with a transient increase in serum concentrations of biomarkers of cardiac damage and ventricular dysfunction which improves within 72 h. Over the past decade, there have been emerging studies reporting attenuated mortality benefit amongst individuals who perform the highest volume of exercise. Studies in lifelong male athletes aged above 40 years old show a higher prevalence of high coronary artery calcium scores (>300 Agatston units), a higher coronary plaque burden, and myocardial fibrosis compatible with subclinical myocardial infarction compared with relatively sedentary healthy controls, raising speculation that lifelong intense exercise imposes chronic coronary stress on the heart. This review article will provide a critical analysis of the existing data.

A comprehensive electrocardiographic analysis for young athletes

ECG-based differences between athletes and sedentary adolescents are a frequently investigated subject in sports medicine. Especially, training-induced ECG variations are common in adult athletes and sustained training often leads to anatomical changes in the heart that can yield abnormalities in ECG. Therefore, ECG screening in athletes is important in diagnosis of cardiac problems of young athletes. The present work investigated the ECG characteristics of young athletes in terms of both gender and sedentary healthy young control group differences. Besides comparison between groups, analysis parameters were also investigated within the groups using correlation analysis. ECG characteristics were extracted using wavelet transform-based adaptive algorithms. Results showed that ECGs of athletes demonstrate differences related to gender and compared to young sedentary. Athletes had significantly lower heart rate; higher QTc, P, and T amplitudes; ST segment; and ST, QT, and RR intervals compared to control group (p < 0.05). Proposed new parameter, namely "scalogram" of each wave, was lower in male athletes compared to other groups (p < 0.05). Negative correlation between T wave amplitude and RR interval could be an indicator of long QT syndrome for male athletes. Furthermore, prolongation of QRS interval in athletes could be the underlying reason of changes in T wave amplitude. Findings of this study can propose indicators for understanding the possible diseases as well as help evaluate the sudden changes in athlete's heart.

Biventricular dysfunction and lung congestion in athletes on anabolic androgenic steroids: a speckle tracking and stress lung echocardiography analysis

AIMS

The real effects of the chronic consumption of anabolic-androgenic steroids (AASs) on cardiovascular structures are subjects of intense debate. The aim of the study was to detect by speckle tracking echocardiography (STE) right ventricular (RV) and left ventricular (LV) dysfunction at rest and during exercise stress echocardiography (ESE) in athletes abusing AAS.

METHODS AND RESULTS

One hundred and fifteen top-level competitive bodybuilders were selected (70 males), including 65 athletes misusing AAS for at least 5 years (users), 50 anabolic-free bodybuilders (non-users), compared to 50 age- and sex-matched healthy sedentary controls. Standard Doppler echocardiography, STE analysis, and lung ultrasound at rest and at peak supine-bicycle ESE were performed. Athletes showed increased LV mass index, wall thickness, and RV diameters compared with controls, whereas LV ejection fraction was comparable within the groups. left atrial volume index, LV and RV strain, and LV E/Em were significantly higher in AAS users. Users showed more B-lines during stress (median 4.4 vs. 1.25 in controls and 1.3 in non-users, P < 0.01 vs. users). By multivariable analyses, LV E/Ea (beta coefficient = 0.35, P < 0.01), pulmonary artery systolic pressure (beta = 0.43, P < 0.001) at peak effort and number of weeks of AAS use per year (beta = 0.45, P < 0.001) emerged as the only independent determinants of resting RV lateral wall peak systolic two-dimensional strain. In addition, a close association between resting RV myocardial function and VO2 peak during ESE was evidenced (P < 0.001), with a powerful incremental value with respect to clinical and standard echocardiographic data.

CONCLUSIONS

In athletes abusing steroids, STE analysis showed an impaired RV systolic deformation, closely associated with reduced functional capacity during physical effort, and-during exercise-more pulmonary congestion.

Impact of a 246 Km ultra-marathon running race on heart: Insights from advanced deformation analysis

Although previous studies suggest that prolonged intense exercise such as marathon running transitorily alters cardiac function, there is little information regarding ultramarathon races. Aim of this study was to investigate the acute impact of ultra-endurance exercise (UEE) on heart, applying advanced strain imaging. Echocardiographic assessment was performed the day before and at the finish line of "Spartathlon": A 246 Km ultra-marathon running race. 2D speckle-tracking echocardiography was performed in all four chambers, evaluating longitudinal strain (LS) for both ventricles and atria. Peak strain values and temporal parameters adjusted for heart rate were extracted from the derived curves. Out of 60 participants initially screened, 27 athletes (19 male, age 45 ± 7 years) finished the race in 33:34:27(28:50:38-35:07:07) hours. Absolute values of right (RV) and left ventricular (LV) LS (RVLS -22.9 ± 3.6 pre- to -21.2 ± 3.0% post-, p=0.04 and LVLS -20.9 ± 2.3 pre- to -18.8 ± 2.0 post-, p=0.009) slightly decreased post-race, whereas atrial strain did not change. RV and LV LS decrease was caused mainly by strain impairment of basal regions with apical preservation. Inter-chamber relationships assessed through RV/LV, LV/LA, RV/RA and RA/LA peak values' ratios remained unchanged from pre to post-race. Finally, UEE caused an extension of the systolic phase of cardiac cycle with concomitant diastole reduction (p<0.001 for all strain curves). Conclusively, ventricular LS strain as well as effective diastolic period slightly decreased, whereas atrial strain and inter-chamber relationships remained unchanged after running a 246-km-ultra-marathon race. These changes may be attributed to concomitant pre- and afterload alterations following UEE.

Cardiac MRI findings to differentiate athlete's heart from hypertrophic (HCM), arrhythmogenic right ventricular (ARVC) and dilated (DCM) cardiomyopathy

To provide clinically relevant criteria for differentiation between the athlete’s heart and similar appearing hypertrophic (HCM), dilated (DCM), and arrhythmogenic right-ventricular cardiomyopathy (ARVC) in MRI. 40 top-level athletes were prospectively examined with cardiac MR (CMR) in two university centres and compared to retrospectively recruited patients diagnosed with HCM (n = 14), ARVC (n = 18), and DCM (n = 48). Analysed MR imaging parameters in the whole study cohort included morphology, functional parameters and late gadolinium enhancement (LGE). Mean left-ventricular enddiastolic volume index (LVEDVI) was high in athletes (105 ml/m²) but significantly lower compared to DCM (132 ml/m²; p = 0.001). Mean LV ejection fraction (EF) was 61% in athletes, below normal in 7 (18%) athletes vs. EF 29% in DCM, below normal in 46 (96%) patients (p < 0.0001). Mean RV-EF was 54% in athletes vs. 60% in HCM, 46% in ARVC, and 41% in DCM (p < 0.0001). Mean interventricular myocardial thickness was 10 mm in athletes vs. 12 mm in HCM (p = 0.0005), 9 mm in ARVC, and 9 mm in DCM. LGE was present in 1 (5%) athlete, 8 (57%) HCM, 10 (56%) ARVC, and 21 (44%) DCM patients (p < 0.0001). Healthy athletes’ hearts are characterized by both hypertrophy and dilation, low EF of both ventricles at rest, and increased interventricular septal thickness with a low prevalence of LGE. Differentiation of athlete’s heart from other non-ischemic cardiomyopathies in MRI can be challenging due to a significant overlap of characteristics also seen in HCM, ARVC, and DCM.

Role of Exercise as a Modulating Factor in Arrhythmogenic Cardiomyopathy

PURPOSE OF REVIEW

The review addresses the role of exercise in triggering ventricular arrhythmias and promoting disease progression in arrhythmogenic cardiomyopathy (AC) patients and gene-mutation carriers, the differential diagnosis between AC and athlete's heart and current recommendations on exercise activity in AC.

RECENT FINDINGS

AC is an inherited heart muscle disease caused by genetically defective cell-to-cell adhesion structures (mainly desmosomes). The pathophysiological hallmark of the disease is progressive myocyte loss and replacement by fibro-fatty tissue, which creates the substrates for ventricular arrhythmias. Animal and human studies demonstrated that intense exercise, but not moderate physical activity, may increase disease penetrance, worsen the phenotype, and favor life-threatening ventricular arrhythmias. It has been proposed that in some individuals prolonged endurance sports activity may in itself cause AC (so-called exercise-induced AC). The studies agree that intense physical activity should be avoided in patients with AC and healthy gene-mutation carriers. However, low-to-moderate intensity exercise does not appear detrimental and these patients should not be entirely deprived from the many health benefits of physical activity.

Echocardiographic Screening of Anomalous Origin of Coronary Arteries in Athletes with a Focus on High Take-Off

Anomalous aortic origin of coronary arteries (AAOCA) represents a rare congenital heart disease. However, this disease is the second most common cause of sudden cardiac death in apparently healthy athletes. The aim of this systematic review is to analyze the feasibility and the detection rate of AAOCA by echocardiography in children and adults. A literature search was performed within the National Library of Medicine using the following keywords: coronary artery origin anomalies and echocardiography; then, the search was redefined by adding the keywords: athletes, children, and high take-off. Nine echocardiographic studies investigating AAOCA and a total of 33,592 children and adults (age range: 12–49 years) were included in this review. Of these, 6599 were athletes (12–49 years). All studies demonstrated a high feasibility and accuracy of echocardiography for the evaluation of coronary arteries origin as well as their proximal tracts. However, some limitations exist: the incidence of AAOCA varied from 0.09% to 0.39% (up to 0.76%) and was lower than described in computed tomography series (0.3–1.8%). Furthermore, echocardiographic views for the evaluation of AAOCA and the definition of “minor” defects (e.g., high take-off coronary arteries) have not been standardized. An echocardiographic protocol to diagnose the high take-off of coronary arteries is proposed in this article. In conclusion, the screening of AAOCA by echocardiography is feasible and accurate when appropriate examinations are performed; however, specific acoustic windows and definitions of defects other than AAOCA need to be standardized to improve sensitivity and specificity.

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 Impact of Ethnicity on Cardiac Adaptation

Regular intensive exercise is associated with a plethora of electrical, structural and functional adaptations within the heart to promote a prolonged and sustained increase in cardiac output. Bradycardia, increased cardiac dimensions, enhanced ventricular filling, augmentation of stroke volume and high peak oxygen consumption are recognised features of the athlete's heart. The type and magnitude of these adaptations to physical exercise are governed by age, sex, ethnicity, sporting discipline and intensity of sport. Some athletes, particularly those of African or Afro-Caribbean (black) origin reveal changes that overlap with diseases implicated in sudden cardiac death. In such instances, erroneous interpretation has potentially serious consequences ranging from unfair disqualification to false reassurance. This article focuses on ethnic variation in the physiological cardiac adaption to exercise.

Cardiovascular Magnetic Resonance and Sport Cardiology: a Growing Role in Clinical Dilemmas

Exercise training induces morphological and functional cardiovascular adaptation known as the "athlete's heart" with changes including dilatation, hypertrophy, and increased stroke volume. These changes may overlap with pathological appearances. Distinguishing athletic cardiac remodelling from cardiomyopathy is important and is a frequent medical dilemma. Cardiac magnetic resonance (CMR) has a role in clinical care as it can refine discrimination of health from a disease where ECG and echocardiography alone have left or generated uncertainty. CMR can more precisely assess cardiac structure and function as well as characterise the myocardium detecting key changes including myocardial scar and diffuse fibrosis. In this review, we will review the role of CMR in sports cardiology.

Cardiac adaptations in elite female football- and volleyball-athletes do not impact left ventricular global strain values: a speckle tracking echocardiography study

Cardiac adaptations to exercise on an elite level have been well studied. Strain analysis by speckle tracking echocardiography has emerged as a tool for sports cardiologists to assess the nature of hypertrophy in athletes' hearts. In prior studies, strain values generally did not change in physiological adaptations to exercise but were reduced in pathological hypertrophy. However, research in this field has focused almost solely on male athletes. Purpose of the present study is to investigate strain values in the hearts of female elite athletes in football and volleyball. In this cross-sectional study echocardiography was performed on 19 female elite football-players, 16 female elite volleyball-players and 16 physically inactive controls. Conventional echocardiographic data was documented as well as left ventricular longitudinal, radial and circumferential strain values gained by speckle tracking echocardiography. The hearts of the female athletes had a thicker septal wall, a larger overall mass and larger atria than the hearts in the control group. Global longitudinal, radial and circumferential strain values did not differ between the athletes and controls or between sporting disciplines. No correlation between septal wall thickness and global strain values could be documented. Cardiac adaptations to elite level exercise in female volleyball and football players do not influence global strain values. This has been documented for male athletes of several disciplines. The present study adds to the very limited control-group comparisons of left ventricular strain values in elite female athletes. The findings indicate that global strain values can be used when assessing the cardiac health in female athletes.

Three-dimensional regional bi-ventricular shape remodeling is associated with exercise capacity in endurance athletes

AIMS

Endurance athletes develop cardiac remodeling to cope with increased cardiac output during exercise. This remodeling is both anatomical and functional and shows large interindividual variability. In this study, we quantify local geometric ventricular remodeling related to long-standing endurance training and assess its relationship with cardiovascular performance during exercise.

METHODS

We extracted 3D models of the biventricular shape from end-diastolic cine magnetic resonance images acquired from a cohort of 89 triathlon athletes and 77 healthy sedentary subjects. Additionally, the athletes underwent cardio-pulmonary exercise testing, together with an echocardiographic study at baseline and few minutes after maximal exercise. We used statistical shape analysis to identify regional bi-ventricular shape differences between athletes and non-athletes.

RESULTS

The ventricular shape was significantly different between athletes and controls (p < 1e-6). The observed regional remodeling in the right heart was mainly a shift of the right ventricle (RV) volume distribution towards the right ventricular infundibulum, increasing the overall right ventricular volume. In the left heart, there was an increment of left ventricular mass and a dilation of the left ventricle. Within athletes, the amount of such remodeling was independently associated to higher peak oxygen pulse (p < 0.001) and weakly with greater post-exercise RV free wall longitudinal strain (p = 0.03).

CONCLUSIONS

We were able to identify specific bi-ventricular regional remodeling induced by long-lasting endurance training. The amount of remodeling was associated with better cardiopulmonary performance during an exercise test.

Cardiac Imaging in the Athlete: Shrinking the "Gray Zone"

PURPOSE OF THE REVIEW

This review will explore frequently encountered diagnostic challenges and summarize the role cardiac imaging plays in defining the boundaries of what constitutes the athlete's heart syndrome versus pathology.

RECENT FINDINGS

Investigations have predominantly focused on differentiating the athlete's heart from potentially lethal pathological conditions that may produce a similar cardiac morphology. Guidelines have identified criteria for identifying definitive pathology, but difficulty arises when individuals fall in the gray zone of expected athletic remodeling and pathology. Transthoracic echo has traditionally been the imaging modality of choice utilizing parameters such as wall thickness, wall:volume ratio, and certain diastolic parameters. Newer echocardiogram techniques such as strain imaging and speckle tracking have potential additive utility but still need further investigation. Cardiac magnetic resonance (CMR) imaging has emerged as an additive technique to help differentiate the phenotypic overlap between these groups. Utilizing gadolinium enhancement and T1 mapping along with its excellent spatial resolution can help distinguish pathology from physiology. Both established and novel cardiac imaging modalities have been used for uncovering the at risk athletes with cardiomyopathies. The issue is of practical importance because athletes are frequently referred to the cardiologist with symptoms of fatigue, palpitations, presyncope, and/or syncope concerned about the safety of their future participation. Imaging is a key component of risk stratification and identifying normal findings of the developed athlete and those "at-risk" athletes.

Limitations of Electrocardiography for Detecting Left Ventricular Hypertrophy or Concentric Remodeling in Athletes

BACKGROUND

Electrocardiography (ECG) is used to screen for left ventricular hypertrophy (LVH), but common ECG-LVH criteria have been found less effective in athletes. The purpose of this study was to comprehensively evaluate the value of ECG for identifying athletes with LVH or a concentric cardiac phenotype.

METHODS

A retrospective analysis of 196 male Division I college athletes routinely screened with ECG and echocardiography within the Stanford Athletic Cardiovascular Screening Program was performed. Left-ventricular mass and volume were determined using echocardiography. LVH was defined as left ventricular mass (LVM) >102 g/m²; a concentric cardiac phenotype as LVM-to-volume (M/V) ≥1.05 g/mL. Twelve-lead electrocardiograms including high-resolution time intervals and QRS voltages were obtained. Thirty-seven previously published ECG-LVH criteria were applied, of which the majority have never been evaluated in athletes. C-statistics, including area under the receiver operating curve (AUC) and likelihood ratios were calculated.

RESULTS

ECG lead voltages were poorly associated with LVM (r = 0.18-0.30) and M/V (r = 0.15-0.25). The proportion of athletes with ECG-LVH was 0%-74% across criteria, with sensitivity and specificity ranging between 0% and 91% and 27% and 99.5%, respectively. The average AUC of the criteria in identifying the 11 athletes with LVH was 0.57 (95% confidence interval [CI] 0.56-0.59), and the average AUC for identifying the 8 athletes with a concentric phenotype was 0.59 (95% CI 0.56-0.62).

CONCLUSION

The diagnostic capacity of all ECG-LVH criteria were inadequate and, therefore, not clinically useful in screening for LVH or a concentric phenotype in athletes. This is probably due to the weak association between LVM and ECG voltage.

Detection and Management of Heart Disease in Athletes

Primary care clinicians fulfill critical roles of screening for, diagnosing, and managing cardiovascular disease. In young athletes, primary structural and electrical diseases are the focus. Coronary artery disease is the chief concern in older athletes. Sudden cardiac arrest may be the initial presentation of disease and is more common in young athletes than historically appreciated. The traditional preparticipation evaluation, or sports physical, is limited in its ability to accurately raise suspicion of underlying disease. The 12-lead electrocardiogram is a more accurate screening tool. Contemporary risk stratification and treatment protocols may allow for safe return to sport on a case-by-case basis.

Echocardiographic assessment of children participating in regular sports training

OBJECTIVE:

The aim of the present study was to determine the effects of a well-controlled endurance training program on cardiac functions and structures in healthy children and to define whether training hours per week and type of sports affect the training-induced cardiovascular response.

METHODS:

Echocardiographic recordings were obtained in 126 children who systematically participated in sports training for at least 1 year (study group), and the results were compared with the values obtained in 62 normal children who did not actively engage in any sports activity (control group). The two groups were comparable for age, sex, and body mass index. Study group participants were divided into two groups according to the duration of physical activity (training hours per week, <8 h and >8 h) and five groups according to the cardiovascular demand of sports type. Clinical examination, resting electrocardiogram, two-dimensional, M-mode, and Doppler echocardiography were obtained in all participants.

RESULTS:

Left ventricle wall dimensions, left atrial diameters, and aortic measurements were significantly higher in the study group. The mean mitral E/A ratio was also significantly higher in the training group than in untrained subjects (p<0.001). Echocardiographic measurements were similar between different sports type participants in the study group. However, aortic root diameter, left atrial diameter, and left ventricle posterior wall diastolic thickness were higher in children training >8 h/week than in children training <8 h/week in the study group.

CONCLUSION:

The present study showed that the echocardiographic parameters of children participating in regular sports training activities statistically significantly exceeded the parameters of untrained controls. These parameters were mostly dependent on the duration of training hours per week.

Asymptomatic bradycardia amongst endurance athletes

It is established that an intensive training results in a lower average resting heart rate. Management of bradycardia in an athlete can be difficult given the underlying mechanisms are not clearly understood. The authors reviewed the different mechanisms described in the literature, including recent advances in physiology regarding remodeling of ion channels, which may partially explain bradycardia in athletes. Sinus bradycardia amongst athletes, especially endurance focused athletes, is common but difficult to apprehend. The underlying mechanisms are observably of multifactorial origin and likely incompletely elucidated by the current body of knowledge.

Cardiac magnetic resonance based deformation imaging: role of feature tracking in athletes with suspected arrhythmogenic right ventricular cardiomyopathy

Both, arrhythmogenic right ventricular cardiomyopathy (ARVC) and regular training are associated with right ventricular (RV) remodelling. Cardiac magnetic resonance (CMR) is given an important role in the diagnosis of ARVC in current task force criteria (TFC), however, they contain no cut-off values for athletes. We aimed to confirm the added value of feature tracking and to provide new cut-off values to differentiate between ARVC and athlete's heart. Healthy athletes with training of minimal 15 h/week (n = 34), patients with definite ARVC (n = 34) and highly trained athletes with ARVC (n = 8) were examined by CMR. Left and right ventricular volumes and masses were determined. Global right and left ventricular, and regional strain analysis for the RV free wall was performed using feature tracking on balanced steady-state free precession cine images. 94% of healthy athletes showed RV dilatation of the proposed TFC, 14.7% showed RV ejection fraction (RVEF) between 45-50%, none of them had RVEF < 45%. Although RVEF showed the highest accuracy in differentiating between athlete's heart and ARVC, only 37.5% of athletes with ARVC showed RVEF < 45%. The only parameters falling in the pathological range (based on our established cut-off values: > - 25.6 and > - 1.4, respectively) in all athletes with ARVC were the strain and strain rate of the midventricular RV free wall. Establishing RVEF and RV strain analysis provides an important tool to distinguish ARVC from athlete's heart. CMR based regional strain and strain rate values may help to identify ARVC even in highly trained athletes with preserved RVEF.

Left Ventricular Trabeculations in Athletes: Epiphenomenon or Phenotype of Disease?

PURPOSE OF REVIEW

Excessive trabeculation attracting a diagnosis of left ventricular noncompaction cardiomyopathy (LVNC) has been reported in ostensibly healthy athletes. This review aims to explain why this occurs and whether this represents a spectrum of athletic physiological remodelling or unmasking of occult cardiomyopathy.

RECENT FINDINGS

Genetic studies have yet to identify a dominant mutation associated with the LVNC phenotype and reported gene mutations overlap with many distinct cardiomyopathies and ion channel disorders, implying that the phenotype is shared across different genetic conditions. Large contemporary cohort studies indicate that current LVNC imaging criteria are oversensitive and not predictive of adverse clinical outcomes. The majority of excessive LV trabeculation, as assessed by current quantification methods, is not due to cardiomyopathy but forms part of the normal continuum in health with potential contributions from cardiac remodelling processes. The study of rare, severe LVNC phenotypes may yield insights into an underlying molecular pathogenesis but in the absence of a universally accepted definition, contamination with aetiologically distinct conditions expressing a similar phenotype will remain an issue. Automated, objective quantification of trabeculation will help to define the normal distribution using big data without the constraint of wide interobserver variation.

Left Ventricular Hypertrophy in Athletes: Differentiating Physiology From Pathology

PURPOSE OF REVIEW

The changes that occur in athlete's heart are influenced by a number of factors including age, gender, ethnicity and the type of cardiovascular training. It is therefore important that the clinician is able to integrate all of these factors when assessing athletes to be able to guide investigations appropriately and to distinguish pathology from physiology. This review discusses the potential diagnostic conundrums when trying to differentiate physiological left ventricular hypertrophy from pathological hypertrophic cardiomyopathy in athletes. The mechanism of physiological and pathological hypertrophy is discussed together with history, clinical and investigational findings that can help to identify pathology.

RECENT FINDINGS

Athletes with hypertrophic cardiomyopathy are more likely to have non-concentric left ventricular hypertrophy (LVH), an elevated relative wall thickness, lateral ECG changes and a smaller LV cavity than athletes with physiological LVH. Certain diastolic echocardiographic parameters when used as part of an algorithm (e'; E/E'; E/A) can help to distinguish physiology from pathology, and there is evidence that assessment of global longitudinal strain during exercise echocardiography may be of use in the future. Cardiac MRI is an important imaging modality that can have an additive effect over echocardiography in the diagnosis of cardiomyopathy. Late gadolinium enhancement is a recognised advantage for cardiac magnetic resonance to allow detection of fibrosis in hypertrophic cardiomyopathy. T1 mapping and extracellular volume quantification may be a tool for the future to help distinguish athlete's heart from HCM. Cardiac adaptation to exercise and training in athletes, the athlete's heart causes electrophysiological and geometric changes that may mimic mild phenotypes of a pathological cardiomyopathy. This review article summarises a systematic approach to the assessment of left ventricular hypertrophy in athletes and describes pertinent clinical and investigation findings that can help to differentiate physiology from pathology.

Athlete's Heart and Left Heart Disease

Physical activity comprises all muscular activities that require energy expenditure. Regular sequence of structured and organized exercise with the specific purpose of improving wellness and athletic performance is defined as a sports activity.Exercise can be performed at various levels of intensity and duration. According to the social context and pathways, it can be recreational, occupational, and competitive. Therefore, the training burden varies inherently and the heart adaptation is challenging.Although a general agreement on the fact that sports practice leads to metabolic, functional and physical benefits, there is evidence that some athletes may be subjected to adverse outcomes. Sudden cardiac death can occur in apparently healthy individuals with unrecognized cardiovascular disease.Thus, panels of experts in sports medicine have promoted important pre-participation screening programmes aimed at determining sports eligibility and differentiating between physiological remodeling and cardiac disease.In this review, the most important pathophysiological and diagnostic issues are discussed.

What May the Future Hold for Sports Cardiology?

The field of sports cardiology has advanced significantly over recent times. It has incorporated clinical and research advances in cardiac imaging, electrophysiology and exercise physiology to enable better diagnostic and therapeutic management of our patients. One important endeavour has been to try and better differentiate athletic cardiac remodelling from inherited cardiomyopathies and other pathologies. Whilst our diagnostic tools have improved, there have also been errors resulting from assumptions that the pathological traits observed in the general population would be generalisable to athletic populations. However, we have learnt that athletes with hypertrophic cardiomyopathy, for example, have many unique features when compared with non-athletic patients with hypertrophic cardiomyopathy. We are learning the limitations of cross-sectional observations and a greater number of prospective studies have been initiated which should enable us to more confidently interrogate the associations between exercise, cardiac remodelling and clinical outcomes. This review of the field enables some of the world's experts in sports cardiology to reflect on where there is a need for research focus to advance knowledge and clinical care in sports cardiology.

Preparticipation Screening of Young Athletes: Identifying Cardiovascular Disease

The most common cause of sudden cardiac death (SCD) in young athletes in the United States is "autopsy-negative sudden unexplained death." This makes it extremely difficult to screen for and diagnose predisposing cardiovascular conditions before athletic participation. The goal of the preparticipation physical examination is to detect risk factors for SCD, make risk-based decisions regarding the need for further workup, and ultimately recommend for or against participation. Current evidence recommends universal screening of young athletes using the 14-point American Heart Association preparticipation cardiovascular checklist. Electrocardiograms and echocardiograms are not currently recommended in the United States to screen 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.

Sudden improvement in ventricular repolarization abnormality after a short detraining period in an athlete

We describe the case of a 17-year-old male soccer player with T-wave inversion in precordial leads in resting electrocardiography, which also disclosed sinus bradycardia, early repolarization, and increased QRS voltage. These findings strongly suggested cardiomyopathy. The patient's T-wave inversion disappeared during only 2 weeks of detraining, and it re-appeared 2 weeks after resumption of intensive training. This sudden change in electrocardiographic parameters over a short period helped in identifying the adolescent as having athlete's heart.

Athletes and the Aorta: Normal Adaptations and the Diagnosis and Management of Pathology

OPINION STATEMENT

Over a hundred years ago, physicians first recognized that participation in regular, vigorous training resulted in enlargement of the heart. Since that time, the term "athlete's heart" has entered the medical lexicon as a global expression encompassing the electrical, functional, and morphological adaptations that develop in response to physical training. Exercise-induced adaptations of the aorta, which is also exposed to large hemodynamic stresses during prolonged endurance exercise or resistance training, are less well recognized. Young athletes tend to have slightly larger aortas than their sedentary counterparts; however, this rarely exceeds normal ranges for the general population. A systematic approach is advised when presented with an athlete with aortic enlargement. The size of the aorta needs to be first put in the context of the athlete's age, sex, size, and sporting endeavors; however, even in the largest young athletes, the aortic root rarely exceeds 4 cm in men or 3.4 cm in women. A comprehensive evaluation is advised which includes a detailed family history and a thorough physical examination evaluating for signs of any defined connective tissue disorder associated with aortopathy. Downstream testing is then tailored for the individual and may include further tomographic imaging, opthalmology review, and genetic testing. This should ideally be performed at a specialist center. Management of athletes with an aortopathy includes tailoring athletic activity, medical management with strict impulse control, and, in some cases, prophylactic surgery. The issue of sporting eligibility should be individualized and if disqualification is necessary, this should be undertaken by a sports cardiologist or an expert in aortic disease with experience in dealing with an athletic population.

Myocardial performance index in female athletes

BACKGROUND

Long-term intensive training leads to morphological and mechanical changes in the heart generally known as "athlete's heart". Previous studies have suggested that the diastolic and systolic function of the ventricles is unaltered in athletes compared to sedentary. The purpose of this study was to investigate myocardial performance index (MPI) by pulsed wave Doppler (PWD) and by tissue Doppler imaging (TDI) in female elite athletes compared to sedentary controls.

METHODS

The study consisted of 32 athletes (mean age 20 ± 2 years) and 34 sedentary controls (mean age 23 ± 2 years). MPI by PWD and TDI were measured in the left (LV) and right ventricle (RV) in both groups. Moreover, comparisons of MPI by the two methods and between the LV and RV within the two groups were made.

RESULTS

There were no significant differences in MPI between athletes and controls (p > 0.05), whereas the LV had significantly higher MPI compared to RV (p < 0.001, in athletes and controls). The agreement and the correlation between the two methods measuring MPI showed low agreement and no correlation (athletes RV r = -0.027, LV r = 0.12; controls RV r = 0.20, LV r = 0.30).

CONCLUSION

The global function of the LV and RV measured by MPI with PWD and TDI is similar in female athletes compared to sedentary controls. Conversely, both MPI by PWD and by TDI shows a significant difference between the LV and RV. However, the agreement and correlation between conventional methods of measuring MPI by PWD compared to MPI by TDI is very poor in both these populations.