Cardiac Imaging and Stress Testing Asymptomatic Athletes to Identify Those at Risk of Sudden Cardiac Death

The role of coronary CT angiography in athletes

The sudden death of a young or high-level athlete or adolescent during recreational sports is one of the events with the greatest impact on public opinion in modern society. Sudden cardiac death (SCD) is the principal medical cause of death in athletes and can be the first and last clinical presentation of underlying disease. To prevent such episodes, pre-participation screening has been introduced in many countries to guarantee cardiovascular safety during sports and has become a common target among medical sports/governing organizations. Different cardiac conditions may cause SCD, with incidence depending on definition, evaluation methods, and studied populations, and a prevalence and etiology changing according to the age of athletes, with CAD most frequent in master athletes, while coronary anomalies and non-ischemic causes prevalent in young. To detect silent underlying causes early would be of considerable clinical value. This review summarizes the pre-participation screening in athletes, the specialist agonistic suitability visit performed in Italy, the anatomical characteristics of malignant coronary anomalies, and finally, the role of coronary CT angiography in such arena. In particular, the anatomical conditions suggesting potential disqualification from sport, the post-treatment follow-up to reintegrate young athletes, the diagnostic workflow to rule-out CAD in master athletes, and their clinical management are analyzed.

What is the most appropriate age for the first cardiac screening of athletes?

For sporting organisations that conduct screening of athletes, there are very few consistent guidelines on the age at which to start. Our review found the total rate of sudden cardiac arrest or death is very low between the ages of 8-11 years (less than 1/100,000/year), increasing to 1-2/100,000/year in both elite athletes and community athletes aged 12-15 years and then steadily increases with age. The conditions associated with sudden cardiac death in paediatric athletes and young adult athletes are very similar with some evidence that death from coronary artery abnormalities occurs more frequently in athletes 10-14 years old. The decision when to begin a screening program involves a complex interplay between requirements and usual practices in a country, the rules of different leagues and programs, the age of entry into an elite program, the underlying risk of the population and the resources available. Given the incidence of sudden cardiac arrest or death in young people, we recommend beginning cardiac screening no earlier than 12 years (not later than 16 years). The risk increases with age, therefore, starting a program at any point after age 12 has added value. Importantly, anyone with concerning symptoms (e.g. collapse on exercise) or family history of an inherited cardiac condition should see a physician irrespective of age. Finally, no screening program can capture all abnormalities, and it is essential for organisations to implement a cardiac emergency plan including training on recognition and response to sudden cardiac arrest and prompt access to resuscitation, including defibrillators.

Low rates of myocardial fibrosis and ventricular arrhythmias in recreational athletes after SARS-CoV-2 infection

Introduction

High rates of cardiac involvement were reported in the beginning of the coronavirus disease 2019 (COVID-19) pandemic. This led to anxiety in the athletic population. The current study was set up to assess the prevalence of myocardial fibrosis and ventricular arrhythmias in recreational athletes with the recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Methods

Consecutive adult recreational athletes (≥18 years old, ≥4 h of mixed type or endurance sports/week) underwent systematic cardiac evaluation after a prior confirmed COVID-19 infection. Evaluation included clinical history, electrocardiogram (ECG), 5-day Holter monitoring, and cardiac magnetic resonance (CMR) imaging with simultaneous measurement of high-sensitive cardiac Troponin I. Data from asymptomatic or mildly symptomatic athletes (Group 1) were compared with those with moderate to severe symptoms (Groups 2-3). Furthermore, a comparison with a historical control group of athletes without COVID-19 (Master@Heart) was made.

Results

In total, 35 athletes (18 Group 1, 10 female, 36.9 ± 2.2 years, mean 143 ± 20 days following diagnosis) were evaluated. The baseline characteristics for the Group 1 and Groups 2-3 athletes were similar. None of the athletes showed overt myocarditis on CMR based on the updated Lake Louise criteria for diagnosis of myocarditis. The prevalence of non-ischemic late gadolinium enhancement [1 (6%) Group 1 vs. 2 (12%) Groups 2-3; p = 0.603] or ventricular arrhythmias [1 Group 1 athlete showed non-sustained ventricular tachycardia (vs. 0 in Groups 2-3: p = 1.000)] were not statistically different between the groups. When the male athletes were compared with the Master@Heart athletes, again no differences regarding these criteria were found.

Conclusion

In our series of recreational athletes with prior confirmed COVID-19, we found no evidence of ongoing myocarditis, and no more detection of fibrosis or ventricular arrhythmias than in a comparable athletic pre-COVID cohort. This points to a much lower cardiac involvement of COVID-19 in athletes than originally suggested.

No adverse association between exercise exposure and diffuse myocardial fibrosis in male endurance athletes

The potential association between endurance exercise and myocardial fibrosis is controversial. Data on exercise exposure and diffuse myocardial fibrosis in endurance athletes are scarce and conflicting. We aimed to investigate the association between exercise exposure and markers of diffuse myocardial fibrosis by cardiovascular magnetic resonance imaging (CMR) in endurance athletes. We examined 27 healthy adult male competitive endurance athletes aged 41 ± 9 years and 16 healthy controls in a cross sectional study using 3 Tesla CMR including late gadolinium enhancement and T1 mapping. Athletes reported detailed exercise history from 12 years of age. Left ventricular total mass, cellular mass and extracellular mass were higher in athletes than controls (86 vs. 58 g/m2, 67 vs. 44 g/m2 and 19 vs. 13 g/m2, all p < 0.01). Extracellular volume (ECV) was lower (21.5% vs. 23.8%, p = 0.03) and native T1 time was shorter (1214 ms vs. 1268 ms, p < 0.01) in the athletes. Increasing exercise dose was independently associated with shorter native T1 time (regression coefficient - 24.1, p < 0.05), but expressed no association with ECV. Our results indicate that diffuse myocardial fibrosis has a low prevalence in healthy male endurance athletes and do not indicate an adverse dose-response relationship between exercise and diffuse myocardial fibrosis in healthy athletes.

Left Ventricular Responses during Exercise in Highly Trained Youth Athletes: Echocardiographic Insights on Function and Adaptation

There is an increase in the prevalence of elite youth sports academies, whose sole aim is to develop future elite athletes. This involves the exposure of the child and adolescent athlete to high-volume training during a period of volatile growth. The large amount of data in this area has been garnered from the resting echocardiographic left ventricular (LV) evaluation of the youth athlete; while this can provide some insight on the functional adaptations to training, it is unable to elucidate a comprehensive overview of the function of the youth athletes' LV during exercise. Consequently, there is a need to interrogate the LV responses in-exercise. This review outlines the feasibility and functional insight of capturing global indices of LV function (Stroke Index-SVIndex and Cardiac Index-QIndex), systolic and diastolic markers, and cardiac strain during submaximal and maximal exercise. Larger SVI and QI were noted in these highly trained young athletes compared to recreationally active peers during submaximal and maximal exercise. The mechanistic insights suggest that there are minimal functional systolic adaptions during exercise compared to their recreationally active peers. Diastolic function was superior during exercise in these young athletes, and this appears to be underpinned by enhanced determinants of pre-load.

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.

The role of cardiac computed tomography in sports cardiology: back to the future!

In recent years, the role of pre-participation evaluation (PPE) in the prevention of sudden cardiac death in competitive athletes has become evident. Most physicians routinely supplement assessment by resting electrocardiogram with imaging techniques, such as echocardiography. The primary goal of imaging in the clinical assessment of competitive athletes is to exclude cardiovascular conditions associated with adverse outcomes. Cardiac computed tomography is emerging as an important technique for stratifying cardiovascular risk and assessing coronary artery disease (CAD), particularly in master athletes. Conversely, in young athletes, this technique has the best non-invasive coronary artery resolution and provides valuable details on coronary artery anatomy. Recent technical developments have brought about a dramatic reduction in radiation exposure, a major drawback of this diagnostic method; nowadays cardiac computed tomography may be performed at a dose of barely one millisievert. The present review provides a practical guide for the use of cardiac computed tomography in the PPE of competitive athletes, with a specific focus on its value for detecting congenital coronary anomalies and CAD in young and master athletes, respectively.

Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) encompasses a group of conditions characterized by right ventricular fibrofatty infiltration, with a predominant arrhythmic presentation. First described in the late 1970s and early 1980s, it is now frequently recognized to have biventricular involvement. The prevalence is ∼1:2,000 to 1:5,000, depending on geographic location, and it has a slight male predominance. The diagnosis of ARVC is determined on the basis of fulfillment of task force criteria incorporating electrophysiological parameters, cardiac imaging findings, genetic factors, and histopathologic features. Risk stratification of patients with ARVC aims to identify those who are at increased risk of sudden cardiac death or sustained ventricular tachycardia. Factors including age, sex, electrophysiological features, and cardiac imaging investigations all contribute to risk stratification. The current management of ARVC includes exercise restriction, β-blocker therapy, consideration for implantable cardioverter-defibrillator insertion, and catheter ablation. This review summarizes our current understanding of ARVC and provides clinicians with a practical approach to diagnosis and management.

Sudden cardiac death in sports: could we save Pheidippides?

Hereditary diseases under the age of 35 are the most common underlying heart disease, leading to sudden cardiac death (SCD) in competitive sports, while in older people, atherosclerotic coronary artery disease (CAD) is the main cause. The following preventive measures are recommended: (a) The pre-participation cardiovascular screening, (b) the genetic testing, (c) the use of implantable cardioverter-defibrillator (ICD), (d) the prohibition of doping in sports, (e) the prevention of 'exercise-induced' cardiac complications, (f) the reduction of high-risk factors for CAD, and (g) the use of cardiopulmonary resuscitation. The cost-effectiveness of the electrocardiograms in the pre-participation screening programs remains questionable. Genetic testing is recommended in borderline cases and positive family history. Athletes with ICD can, under certain conditions, participate in competitive sports. Excessive endurance exercise appears to harm the endothelium, promotes inflammatory processes and leads to fibrosis in the myocardium, and calcium deposition in the coronary vessels. Cardiac arrest may be reversed if cardiopulmonary resuscitation is performed and a defibrillator is immediately used. Thus, equipping all fields with automatic external defibrillators are recommended.

Normative cardiopulmonary exercise data for endurance athletes: the Cardiopulmonary Health and Endurance Exercise Registry (CHEER)

AIMS

Accurate interpretation of cardiopulmonary exercise testing (CPET) relies on age, gender, and exercise modality-specific reference values. To date, clinically applicable CPET reference values derived from a source population of endurance athletes (EAs) have been lacking. The purpose of this study was to generate CPET reference values for use in the clinical assessment of EA.

METHODS AND RESULTS

Prospective data accrued during the clinical care of healthy EA were used to derive CPET reference values and to develop novel equations for V˙O2peak. The performance of these equations was compared to the contemporary standard of care equations and assessed in a discrete EA validation cohort. A total of 272 EA (age = 42 ± 15 years, female = 31%, V˙O2peak = 3.6 ± 0.83 L/min) met inclusion criteria and comprised the derivation cohort. V˙O2peak prediction equations derived from general population cohorts described a modest amount of V˙O2peak variability [R2 = 0.58-0.70, root mean square error (RMSE) = 0.46-0.54 L/min] but were mis-calibrated (calibration-in-the-large = 0.45-1.18 L/min) among EA leading to significant V˙O2peak underestimation. Newly derived, externally validated V˙O2peak prediction equations for EA that included age, sex, and height for both treadmill (R2 = 0.74, RMSE = 0.42 L/min) and cycle ergometer CPET (Cycle: R2 = 0.69, RMSE = 0.42 L/min) demonstrated improved accuracy.

CONCLUSION

Commonly used V˙O2peak prediction equations derived from general population cohorts perform poorly among competitive EA. Newly derived CPET reference values including novel V˙O2peak prediction equations may improve the clinical utility of CPET in this rapidly growing patient population.

Sink or swim: innovations in aquatic health

Since the first modern Olympic Games in 1896, the aquatic sports have expanded both in participation and innovation over the last century. Beginning with swimming, diving, water polo, and later additions of artistic swimming, open water swimming and high diving, the aquatics sports represent a core pillar of Olympic disciplines. The rapid expansion of aquatic disciplines necessitated the foundation of the Fédération Internationale de Natation (FINA) in 1908, to govern the development of aquatic sports. The amateur spectacle has been slowly replaced with an increased focus on health and performance by dedicated professional athletes and support teams, resulting in the development of new innovations. In the early years, innovations largely centered on technical equipment such as bathing suit and springboard design. In more recent years, research and innovation have shifted focus to health and its impact on performance, including but not limited to changes in training methods, nutrition, injury and illness reduction through surveillance and access to education for athletes, coaches, and support personnel. An increased awareness on factors that affect athlete health have also driven safety innovations including the development of Nutrition and Relative Energy Deficiency in Sport Clinical Assessment Tool, the Sport Mental Health Assessment and Recognition Tools and safeguarding from harassment and abuse through embedding athletes' right to safe sport in underpinning statutory documents. While the future of aquatic health innovations remains undefined, there are many potential opportunities for research and knowledge translation as the aquatic sports continue to evolve and adapt over time.

High Prevalence of Pericardial Involvement in College Student Athletes Recovering From COVID-19

OBJECTIVES

This study sought to explore the spectrum of cardiac abnormalities in student athletes who returned to university campus in July 2020 with uncomplicated coronavirus disease 2019 (COVID-19).

BACKGROUND

There is limited information on cardiovascular involvement in young individuals with mild or asymptomatic COVID-19.

METHODS

Screening echocardiograms were performed in 54 consecutive student athletes (mean age 19 years; 85% male) who had positive results of reverse transcription polymerase chain reaction nasal swab testing of the upper respiratory tract or immunoglobulin G antibodies against severe acute respiratory syndrome coronavirus type 2. Sequential cardiac magnetic resonance imaging was performed in 48 (89%) subjects.

RESULTS

A total of 16 (30%) athletes were asymptomatic, whereas 36 (66%) and 2 (4%) athletes reported mild and moderate COVID-19 related symptoms, respectively. For the 48 athletes completing both imaging studies, abnormal findings were identified in 27 (56.3%) individuals. This included 19 (39.5%) athletes with pericardial late enhancements with associated pericardial effusion. Of the individuals with pericardial enhancements, 6 (12.5%) had reduced global longitudinal strain and/or an increased native T1. One patient showed myocardial enhancement, and reduced left ventricular ejection fraction or reduced global longitudinal strain with or without increased native T1 values was also identified in an additional 7 (14.6%) individuals. Native T2 findings were normal in all subjects, and no specific imaging features of myocardial inflammation were identified. Hierarchical clustering of left ventricular regional strain identified 3 unique myopericardial phenotypes that showed significant association with the cardiac magnetic resonance findings (p = 0.03).

CONCLUSIONS

More than 1 in 3 previously healthy college athletes recovering from COVID-19 infection showed imaging features of a resolving pericardial inflammation. Although subtle changes in myocardial structure and function were identified, no athlete showed specific imaging features to suggest an ongoing myocarditis. Further studies are needed to understand the clinical implications and long-term evolution of these abnormalities in uncomplicated COVID-19.

Routine pre-employment echocardiography assessment in young adults: cost and benefits

BACKGROUND

Conventional echocardiography is a safe, available, and accurate tool for cardiac structural and functional evaluation, but it should not cancel clinical assessment and history tacking, and indeed both are complementary. A pre-employment assessment is important for employees and community safety and suitability for a specific work requirement.

RESULTS

Aiming to assess the value of routine pre-employment echocardiography for the detection of cardiac abnormalities, we examined seven hundred ninety-five persons who were routinely referred to us for pre-employment conventional echocardiography. Only 9 persons had structural cardiac abnormalities (1.3%) and distributed as follows: two had bicuspid aortic valve with isolated aortic regurgitation, one of them had mild AR, and the other had moderate AR. Two cases had mitral valve prolapse, one of them had trivial MR, while the other had a flail anterior leaflet with severe MR. One patient had atrial septal defect 1.5 cm with mild pulmonary hypertension and right-sided chambers dilatation. One patient had dextrocardia (situs inversus totalis) without other cardiac problems. One had moderate pulmonary hypertension and modest right-sided chambers dilation. Two patients had left ventricular hypertrophy. Surprisingly, we did not detect rheumatic valvular heart disease. The money cost of echocardiography tests for those 795 persons was 198,750 Egyptian pounds (LE); their transportation cost was about 19.800LE. The total group time cost of the tests was 265 h, total time lost at the waiting room was 1590 h, total transportation time lose was 2385 h, so the total time cost was about 4000 h. Using psychological stress questionnaire, 33 participants (4.2%) had results suggestive of a low sense of psychological pressure due to echocardiography examination, 221 participants (27.8%) had results suggestive of a moderate feeling of stress, while 541 participants (68%) had results suggestive of a high sense of stress.

CONCLUSION

We recommend against routine echocardiography for cardiac assessment in pre-employment assessment and to do it only for persons with abnormal clinical or ECG findings.

Assessment of Structure, Function, and Rhythm of the Heart with Echocardiography and Electrocardiography in Adolescent Swimmers

The aim of this study was to evaluate the cardiac parameters by using electrocardiography and echocardiography in adolescent swimmers. Twenty-two adolescent swimmers and 22 gender- and age-matched sedentary controls admitted to our center between November 2018 and May 2019 were included in this study. In addition to demographical characteristics, participants were assessed via a 12-lead electrocardiography and two-dimensional echocardiography for cardiac function. On the echocardiography, end-systolic and end-diastolic interventricular septum, end-systolic and end-diastolic left ventricular posterior wall thicknesses, left atrial width, Tricuspid E, left ventricular mass and left ventricular mass index were higher in the swimmers when compared to the sedentary controls (P < 0.05). On the electrocardiography, Tp-e duration which reflects ventricular transmural repolarization, and Tp-e/QT and Tp-e/corrected QT ratios were higher in the swimmers than the sedentary controls (P < 0.05). In conclusion, swimming exercise in children leads to concentric thickening of left ventricle and induces an increase in Tp-e duration, and Tp-e/QT and Tp-e/corrected QT ratios, which are the novel markers for risk of ventricular arrhythmias.

Bicuspid aortic valve and sports: From the echocardiographic evaluation to the eligibility for sports competition

Bicuspid aortic valve (BAV) is the most common congenital heart defect in adults. Although a BAV may remain without clinical consequences for a lifetime, it can deteriorate in aortic valve stenosis and regurgitation and aortic dilatation. Unfortunately, the impact of regular training on patients with BAV and its natural course is not fully understood, although preliminary evidence suggests that the progression of valvular disease occurs primarily in an independent manner from sports practice. The current review aims to report how to perform a comprehensive echocardiographic examination in athletes with BAV and analyze the current literature on the influence of sports practice and how it impacts the aortic valve in athletes with BAV. The article also summarizes the current recommendations on sports eligibility and disqualification for competitive athletes with BAV.

Diagnostic and prognostic value of low QRS voltages in cardiomyopathies: old but gold

The interpretation of 12-lead resting electrocardiogram (ECG) in patients with a definitive diagnosis or with the suspicion of a cardiomyopathy represents a cornerstone for the diagnostic work up and management of patients. Although low electrocardiographic QRS voltages (LQRSV) detected by 12-lead resting ECG have historically been acknowledged by physicians, in view of recent evidence on the demonstration of myocardial scar by cardiac magnetic resonance and its relevance as a cause of sudden cardiac death even in young individuals, a new interest has been raised about the utility of LQRSV in the clinical practice. Beyond their diagnostic value, LQRSV have also demonstrated a prognostic role in different cardiomyopathies. The present review summarizes the diagnostic and prognostic value of LQRSV in cardiomyopathies, reporting the new evidence, primarily based on advanced imaging studies, supporting the clinical utility of this parameter.

Shock to the Heart: Psychosocial Implications and Applications of Sudden Cardiac Death in the Young

PURPOSE OF REVIEW

Although rare, sudden cardiac death (SCD) in the young is a tragic event, having a dramatic impact upon all involved. The psychosocial burden associated with SCD can leave friends, families, and entire communities bereft. With only limited evidence to describe the volatile emotional reactions associated with a young SCD, there is an urgent need for care providers to better understand the psychological complexities and impacts faced by both at-risk individuals and those directly affected by these tragic events.

RECENT FINDINGS

Current knowledge of the psychosocial implications associated with SCD in the young has recently generated interest in the cardiovascular community, with the goal of addressing prevention strategies (screening), family bereavement, and the psychological impact of at-risk or surviving individuals. With the emergence of novel strategies aimed at reducing the public health impact of SCD in the young, further discussion regarding the psychosocial impact of SCD, encompassing prevention, survivorship, and the downstream communal effects of a young death is required. Support systems and intervention could assist in the management of the associated psychosocial burden, yet there is a lack of clinical guidelines to direct this form of care. There is an important need for multidisciplinary collaboration across subspecialties to provide support to grieving individuals and manage patient well-being throughout the screening process for SCD. This collaborative approach requires the integration of cardiovascular and psychological expertise where relevant.

Characterisation of LV myocardial exercise function by 2-D strain deformation imaging in elite adolescent footballers

Purpose

Few data exist on the descriptions of LV myocardial mechanics and reserve during dynamic exercise of adolescent athletes. The aim of this study was to describe the LV myocardial and cardiopulmonary changes during exercise using 2-D strain deformation imaging.

Methods

Elite adolescent male football players (n = 42) completed simultaneous cardiopulmonary exercise testing (CPET) and exercise echocardiography measurement of LV myocardial deformation by 2-D strain imaging. LV longitudinal and circumferential 2-D strain and strain rates were analyzed at each stage during incremental exercise to a work rate of 150 W. Additionally, exercise LV myocardial deformation and its relation to metabolic exercise parameters were evaluated at each exercise stage and in recovery using repeated measures ANOVA, linear regression and paired t tests.

Results

LV peak systolic baseline 2-D strain (longitudinal: − 15.4 ± 2.5%, circumferential: − 22.5 ± 3.1%) increased with each exercise stage, but longitudinal strain plateaued at 50 W (mean strain reserve − 7.8 ± 3.0) and did not significantly increase compared to subsequent exercise stages (P > 0.05), whilst circumferential strain (mean strain reserve − 11.6 ± 3.3) significantly increased (P < 0.05) throughout exercise up to 150 W as the dominant mechanism of exercise LV contractility increase. Regression analyses showed LV myocardial strain increased linearly relative to HR, VO₂ and O₂ pulse (P < 0.05) for circumferential deformation, but showed attenuation for longitudinal deformation.

Conclusion

This study describes LV myocardial deformation dynamics by 2-D strain and provides reference values for LV myocardial strain and strain rate during exercise in adolescent footballers. It found important differences between LV longitudinal and circumferential myocardial mechanics during exercise and introduces a methodology that can be used to quantify LV function and cardiac reserve during exercise in adolescent athletes.

Cardiac magnetic resonance in arrhythmogenic cardiomyopathies

Over the past few years, the approach to the 'arrhythmic patient' has profoundly changed. An early clinical presentation of arrhythmia is often accompanied by non-specific symptoms and followed by inconclusive electrocardiographic findings. In this scenario, cardiac magnetic resonance (CMR) has been established as a clinical tool of fundamental importance for a correct prognostic stratification of the arrhythmic patient. This technique provides a high-spatial-resolution tomographic evaluation of the heart, which allows studying accurately the ventricular volumes, identifying even segmental kinetic anomalies and properly detecting diffuse or focal tissue alterations through an excellent tissue characterization, while depicting different patterns of fibrosis distribution, myocardial edema or fatty substitution. Through these capabilities, CMR has a pivotal role for the adequate management of the arrhythmic patient, allowing the identification of those phenotypic manifestations characteristic of structural heart diseases. Therefore, CMR provides valuable information to reclassify the patient within the wide spectrum of potentially arrhythmogenic heart diseases, the definition of which remains the major determinants for both an adequate treatment and a poor prognosis. The purpose of this review study was to focus on the role of CMR in the evaluation of the main cardiac clinical entities associated with arrhythmogenic phenomena and to present a brief debate on the main pathophysiological mechanisms involved in the arrhythmogenesis process.

Prevalence and pattern of cardiovascular magnetic resonance late gadolinium enhancement in highly trained endurance athletes

BACKGROUND

Intensive endurance exercise may induce a broad spectrum of right ventricular (RV) adaptation/remodelling patterns. Late gadolinium enhancement (LGE) has also been described in cardiovascular magnetic resonance (CMR) of some endurance athletes and its clinical meaning remains controversial. Our aim was to characterize the features of contrast CMR and the observed patterns of the LGE distribution in a cohort of highly trained endurance athletes.

METHODS

Ninety-three highly trained endurance athletes (> 12 h training/week at least during the last 5 years; 36 ± 6 years old; 53% male) and 72 age and gender-matched controls underwent a resting contrast CMR. In a subgroup of 28 athletes, T1 mapping was also performed.

RESULTS

High endurance training load was associated with larger bi-ventricular and bi-atrial sizes and a slight reduction of biventricular ejection fraction, as compared to controls in both genders (p < 0.05). Focal LGE was significantly more prevalent in athletes than in healthy subjects (37.6% vs 2.8%; p < 0.001), with a typical pattern in the RV insertion points. In T1 mapping, those athletes who had focal LGE had higher extracellular volume (ECV) at the remote myocardium than those without (27 ± 2.2% vs 25.2 ± 2.1%; p < 0.05).

CONCLUSIONS

Highly trained endurance athletes showed a ten-fold increase in the prevalence of focal LGE as compared to control subjects, always confined to the hinge points. Additionally, those athletes with focal LGE demonstrated globally higher myocardial ECV values. This matrix remodelling and potential presence of myocardial fibrosis may be another feature of the athlete's heart, of which the clinical and prognostic significance remains to be determined.

Differentiation between athlete’s heart and dilated cardiomyopathy in athletic individuals

Objective

Distinguishing early dilated cardiomyopathy (DCM) from physiological left ventricular (LV) dilatation with LV ejection fraction <55% in athletes (grey zone) is challenging. We evaluated the role of a cascade of investigations to differentiate these two entities.

Methods

Thirty-five asymptomatic active males with DCM, 25 male athletes in the ‘grey zone’ and 24 male athletes with normal LV ejection fraction underwent N-terminal pro-brain natriuretic peptide (NT-proBNP) measurement, ECG and exercise echocardiography. Grey-zone athletes and patients with DCM underwent cardiovascular magnetic resonance (CMR) and Holter monitoring.

Results

Larger LV cavity dimensions and lower LV ejection fraction were the only differences between grey-zone and control athletes. None of the grey-zone athletes had abnormal NT-proBNP, increased ectopic burden/complex arrhythmias or pathological late gadolinium enhancement on CMR. These features were also absent in 71%, 71% and 50% of patients with DCM, respectively. 95% of grey-zone athletes and 60% of patients with DCM had normal ECG. During exercise echocardiography, 96% grey-zone athletes increased LV ejection fraction by >11% from baseline to peak exercise compared with 23% of patients with DCM (p<0.0001). Peak LV ejection fraction was >63% in 92% grey-zone athletes compared with 17% patients with DCM (p<0.0001). Failure to increase LV ejection fraction >11% from baseline to peak exercise or achieve a peak LV ejection fraction >63% had sensitivity of 77% and 83%, respectively, and specificity of 96% and 92%, respectively, for predicting DCM.

Conclusion

Comprehensive assessment using a cascade of routine investigations revealed that exercise stress echocardiography has the greatest discriminatory value in differentiating between grey-zone athletes and asymptomatic patients with DCM. Our findings require validation in larger studies.

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.

Echocardiographic Pulmonary to Left Atrial Ratio (ePLAR): A Comparison Study between Ironman Athletes, Age Matched Controls and A General Community Cohort

Background: During exercise there is a proportionally lower rise in systemic and pulmonary pressures compared to cardiac output due to reduced vascular resistance. Invasive exercise data suggest that systemic vascular resistance reduces more than pulmonary vascular resistance. The aim of this study was the non-invasive assessment of exercise hemodynamics in ironman athletes, compared with an age matched control group and a larger general community cohort. Methods: 20 ironman athletes (40 ± 11 years, 17 male) were compared with 20 age matched non-athlete controls (43 ± 7 years, 10 male) and a general community cohort of 230 non-athletes individuals (66 ± 11 years, 155 male), at rest and after maximal-symptom limited treadmill exercise stress echocardiography. Left heart parameters (mitral E-wave, e’-wave and E/e’) and right heart parameters (tricuspid regurgitation maximum velocity and right ventricular systolic pressure), were used to calculate the echocardiographic Pulmonary to Left Atrial Ratio (ePLAR) value of the three groups. Results: Athletes exercised for 12.2 ± 0.53 min, age matched controls for 10.1 ± 2.8 min and general community cohort for 8.3 ± 2.6 min. Mitral E/e’ rose slightly for athletes (0.9 ± 1.8), age matched controls (0.6 ± 3.0) and non-athletes (0.4 ± 3.2). Right ventricular systolic pressure increased significantly more in athletes than in both non-athlete cohorts (35.6 ± 17 mmHg vs. 20.4 ± 10.8 mmHg and 18 ± 9.6 mmHg). The marker of trans-pulmonary gradient, ePLAR, rose significantly more in athletes than in both non-athlete groups (0.15 ± 0.1 m/s vs. 0.07 ± 0.1 m/s). Conclusions: Pulmonary pressures increased proportionally four-fold compared with systemic pressures in ironman athletes. This increase in pulmonary vascular resistance corresponded with a two-fold increase in ePLAR. These changes were exaggerated compared with both non-ironman cohorts. Such changes have been previously suggested to lead to right ventricle dysfunction, arrhythmias and sudden cardiac death.

Cardiac MRI improves cardiovascular risk stratification in hazardous occupations

BACKGROUND

The benefit of cardiovascular magnetic resonance Imaging (CMR) in assessing occupational risk is unknown. Pilots undergo frequent medical assessment for occult disease, which threatens incapacitation or distraction during flight. ECG and examination anomalies often lead to lengthy restriction, pending full investigation. CMR provides a sensitive, specific assessment of cardiac anatomy, tissue characterisation, perfusion defects and myocardial viability. We sought to determine if CMR, when added to standard care, would alter occupational outcome.

METHODS

A retrospective review was conducted of all personnel attending the RAF Aviation Medicine Consultation Service (AMCS) for assessment of a cardiac anomaly, over a 2-year period. Those undergoing standard of care (history, examination, exercise ECG, 24 h-Holter and transthoracic echocardiography), and those undergoing a CMR in addition, were identified. The influence of CMR upon the final decision regarding flying restriction was determined by comparing the diagnosis reached with standard of care plus CMR vs. standard of care alone.

RESULTS

Of the ~ 8000 UK military aircrew, 558 personnel were seen for cardiovascular assessment. Fifty-two underwent CMR. A normal TTE did not reliably exclude abnormalities subsequently detected by CMR. Addition of CMR resulted in an upgraded occupational status in 62% of those investigated, with 37% returning to unrestricted duties. Only 8% of referrals were undiagnosed following CMR. All these were cases of borderline chamber dilatation and reduction in systolic function in whom diagnostic uncertainty remained between physiological exercise adaptation and early cardiomyopathy.

CONCLUSIONS

CMR increases the likelihood of a definitive diagnosis and of return to flying. This study supports early use of CMR in occupational assessment for high-hazard occupations.

Acute impact of an endurance race on cardiac function and biomarkers of myocardial injury in triathletes with and without myocardial fibrosis

AIMS

The aim of this study was to investigate the occurrence of myocardial injury and cardiac dysfunction after an endurance race by biomarkers and cardiac magnetic resonance in triathletes with and without myocardial fibrosis.

METHODS AND RESULTS

Thirty asymptomatic male triathletes (45 ± 10 years) with over 10 training hours per week and 55 ± 8 ml/kg per minute maximal oxygen uptake during exercise testing were studied before (baseline) and 2.4 ± 1.1 hours post-race. Baseline cardiac magnetic resonance included cine, T1/T2, late gadolinium enhancement (LGE) and extracellular volume imaging. Post-race non-contrast cardiac magnetic resonance included cine and T1/T2 mapping. Non-ischaemic myocardial fibrosis was present in 10 triathletes (LGE+) whereas 20 had no fibrosis (LGE-). At baseline, LGE + triathletes had higher peak exercise systolic blood pressure with 222 ± 21 mmHg compared to LGE- triathletes (192 ± 30 mmHg, P < 0.01). Post-race troponin T and creatine kinase MB were similarly increased in both groups, but there was no change in T2 and T1 from baseline to post-race with 54 ± 3 ms versus 53 ± 3 ms (P = 0.797) and 989 ± 21 ms versus 989 ± 28 ms (P = 0.926), respectively. However, post-race left atrial ejection fraction was significantly lower in LGE + triathletes compared to LGE- triathletes (53 ± 6% vs. 59 ± 6%, P < 0.05). Furthermore, baseline atrial peak filling rates were lower in LGE -  triathletes (121 ± 30 ml/s/m²) compared to LGE + triathletes (161 ± 34 ml/s/m², P < 0.01). Post-race atrial peak filling rates increased in LGE- triathletes to 163 ± 46 ml/s/m², P < 0.001), but not in LGE + triathletes (169 ± 50ml/s/m², P = 0.747).

CONCLUSION

Despite post-race troponin T release, we did not find detectable myocardial oedema by cardiac magnetic resonance. However, the unfavourable blood pressure response during exercise testing seemed to be associated with post-race cardiac dysfunction, which could explain the occurrence of myocardial fibrosis in triathletes.

Echocardiographic measurements of left ventricular end-diastolic diameter and interventricular septal diameter in collegiate football athletes at preparticipation evaluation referenced to body surface area

Background

Are borderline echocardiogram structural measurements due to physiological adaptation or pathology in college football players? The normal reference data are very limited in this population. We report left ventricular end-diastolic diameter (LVEDD) and interventricular septal diameter (IVSD) echocardiogram findings in college football athletes.

Methods and results

A retrospective cohort review of preparticipation examination transthoracic echocardiogram measurements of LVEDD and IVSD from 375 American collegiate football athletes cleared for participation from the University of Florida in 2012–2017 and University of Georgia in 2010–2015 was performed.

LVEDD and IVSD were analysed by field position (lineman, n=137; non-lineman, n=238), race (black, n=216; white, n=158) and body surface area (BSA) for associations. Values were compared with non-athlete norms, and collegiate football athlete-specific reference norm tables were created.

Twenty-one (5.6%) athletes had LVEDD and 116 (31%) had IVSD measurements above the reference normal non-athlete values. Univariate analyses indicated that the lineman position and increasing BSA were associated with larger values for LVEDD and IVSD. Black race was associated with larger IVSD values, and white race was associated with larger LVEDD values. Player position correlated strongly with BSA (r>0.7); we created normal reference tables for LVEDD and IVSD, stratified by BSA group classification (low, average and high BSA). Proposed clinical cut-offs for normal and abnormal values are reported for raw echocardiograph metrics and BSA-indexed scores.

Conclusions

A significant number of collegiate football athletes had LVEDD and IVSD values above non-athlete norms. BSA-specific normal values help clinicians interpret results for football athletes.

Cardiac Magnetic Resonance Normal Reference Values of Biventricular Size and Function in Male Athlete's Heart

OBJECTIVES

The aim of this meta-analysis was to derive normal reference values of biventricular size and function estimated by cardiac magnetic resonance (CMR) in competitive athletes.

BACKGROUND

Exercise-induced enlargement of cardiac chambers is commonly observed in competitive athletes. However, ventricular dilatation is also a common phenotypic expression of life-threatening cardiomyopathies. The use of CMR for the exclusion of pathology is growing. However, normal reference values have not been established for athletes.

METHODS

The authors conducted a systematic review of English-language studies in the MEDLINE, Scopus, and Cochrane databases investigating biventricular size and function by CMR in athletes. Athletes were divided into endurance, combined, and mixed groups according to the sport practiced. The potential impact of training volume was also evaluated.

RESULTS

Twenty-seven studies and 983 competitive athletes were included for CMR quantification of biventricular size and function. In this review, normal reference values are presented for biventricular size and function to be applied to male competitive athletes according to the disciplines practiced. A significant impact of training volume was demonstrated for the right ventricle: athletes practicing the largest number of training hours per week were those exhibiting the greatest degree of right ventricular remodeling. Notably, biventricular function was not significantly affected by training volume.

CONCLUSIONS

The present meta-analysis defines the normal limits of biventricular size and function estimated by CMR in competitive athletes. The authors suggest using these normal reference values as an alternative to standard upper limits derived from the general population when interpreting CMR images in athletes.

[Place of the exercise stress test at the sportsman]

Is the stress test still part of the useful examinations in the detection of risk heart disease in sports subjects? Should we continue to use it as a surveillance examination in coronary sports patients? Meta-analysis, considering a ST subshift of more than 1mm as a criterion for positivity, underline the low prevalence of abnormal examinations and a significant rate of false-positives. But for the diagnosis of coronary artery disease, it is mainly the evolution of the ST segment to effort or recovery and the occurrence of stress arrhythmias that detect true positivity. When coronary risk is more important (presence of risk factors, resumption of sport, intense and prolonged efforts), it seems lawful to recommend such a review on a regular basis among men over 40 years of age with two risk factors but Also among veterans taking up sport after a period of prolonged inactivity. For the asymptomatic coronary athlete the stress test remains at the centre of the final decision for the resumption of a sport in competition irrespective of the method of revascularization. Of course the stress test, even inevitable, remains flawed in the detection of coronary artery disease in the asymptomatic athlete. However, it provides additional information on the condition of being maximal, and attaching importance to arrhythmias, the tensional profile and the maximum power developed in addition to the ST segment's only study.

Sudden Death and Ventricular Arrhythmias in Athletes: Screening, De-Training and the Role of Catheter Ablation

Athletes enjoy excellent health outcomes including greater longevity relative to non-athletic counterparts. Paradoxically, however, endurance athletic conditioning is associated with an increase in some arrhythmias. This review discusses the potential mechanisms for this paradox and strategies enabling early identification of potentially serious pathologies. Screening remains contentious due to the challenges of identifying relatively rare entities amongst a healthy cohort. The imperfect diagnostic accuracy of all current tests means that screening strategies have potential for harm through incorrect diagnoses as well as the potential for identification of important sub-clinical pathologies. Management of athletes at risk of ventricular arrhythmias and sudden cardiac death is similarly complex. There is much yet to learn about the specific patterns of ventricular arrhythmias in athletes, and the separation of benign from potentially life-threatening remains imperfect. There are some promising advances, however, such as specialised imaging modalities combined with improved electrophysiological diagnostics and therapeutics. Some unique clinical patterns are emerging to advance our understanding and management of athletes with ventricular arrhythmias, requiring specialised skillsets for evaluation and management.

Premature ventricular beats in the athlete: management considerations

INTRODUCTION

Premature ventricular beats (PVBs) in competitive athletes are incidentally found during pre-participation ECG screening. Their clinical significance remains debatable with several studies suggesting they are a benign reflection of athlete's heart, and others proposing they may indicate underlying structural heart disease and heightened risk for sudden cardiac death (SCD). Areas covered: Effective management of athletes with PVBs may best be accomplished using an algorithmic approach for risk stratification with a goal of differentiating benign PVBs from those reflective of underlying cardiomyopathies. Current AHA/ACC consensus recommendations provide a platform for determining optimal medical and invasive therapeutic strategies for symptom control and management of long-term complications without erroneously restricting an athlete's ability to play. Utilizing a shared decision-making model is an optimal method for managing expectations and guiding exercise recommendations. Expert commentary: Though pre-participation ECG screening as the standard of care for competitive athletes remains controversial in the United States, a 12-lead ECG is often the first indication of underlying structural heart disease in athletes with PVBs and can therefore identify athletes at greater risk of SCD. Advancements in non-invasive imaging continue to improve in diagnostic potential and prognostication. Invasive therapies provide a curative strategy for refractory PVBs and PVB-induced cardiomyopathy.

Myocardial Fibrosis in Competitive Triathletes Detected by Contrast-Enhanced CMR Correlates With Exercise-Induced Hypertension and Competition History

OBJECTIVES

This study analyzed the presence of myocardial fibrosis detected by late gadolinium-enhancement (LGE) cardiac magnetic resonance (CMR) in correlation with the performance of competitive triathletes objectified by an exercise test and individual competition history.

BACKGROUND

Myocardial fibrosis detected by LGE CMR has been reported to occur in 0% to 50% of asymptomatic athletes. However, the cause and mechanisms of myocardial fibrosis are unclear.

METHODS

Eighty-three asymptomatic triathletes undergoing >10 training h per week (43 ± 10 years of age; 65% male) and 36 sedentary controls were studied by using LGE and extracellular volume (ECV) CMR. Parameters of physical fitness were measured by spiroergometry. Triathletes reported their lifetime competition results.

RESULTS

LGE CMR revealed focal nonischemic myocardial fibrosis in 9 of 54 (17%) male triathletes (LGE⁺) but in none of the female triathletes (p < 0.05). LGE⁺ triathletes had higher peak exercise systolic blood pressure (213 ± 24 mm Hg) than LGE^- triathletes (194 ± 26 mm Hg; p < 0.05). Furthermore, left ventricular mass index was higher in LGE⁺ triathletes (93 ± 7 g/m²) than in LGE^- triathletes (84 ± 11 g/m²; p < 0.05). ECV in LGE^- myocardium was higher in LGE⁺ triathletes (26.3 ± 1.8%) than in LGE^- triathletes (24.4 ± 2.2%; p < 0.05). LGE⁺ triathletes completed longer cumulative distances in swimming and cycling races and participated more often in middle and Iron Man distances than LGE^- triathletes. A cycling race distance of >1,880 km completed during competition had the highest accuracy to predict LGE, with an area under the curve value of 0.876 (p < 0.0001), resulting in high sensitivity (89%) and specificity (79%). Multivariate analysis identified peak exercise systolic blood pressure (p < 0.05) and the swimming race distance (p < 0.01) as independent predictors of LGE presence.

CONCLUSIONS

Myocardial fibrosis in asymptomatic triathletes seems to be associated with exercise-induced hypertension and the race distances. There appears to be a safe upper limit, beyond which exercise may result in myocardial fibrosis.

The heart remains the core: cardiac causes of poor performance in horses compared to human athletes

Cardiac remodelling occurs in response to exercise and is generally beneficial for athletic performance due to the increase in cardiac output. However, this remodelling also may lead to an increased prevalence of cardiac murmurs and arrhythmias. In most cases, these are not considered to be significant. However, in some cases, there may be potentially deleterious consequences. Whilst sudden cardiac death (SCD) is a rare occurrence, the consequences are catastrophic for both the horse and potentially the rider or driver. Furthermore, the sudden death of a horse in the public arena has negative connotations in regards to public perception of welfare during equestrian sports. Prediction of which individuals might be susceptible to potential deleterious effects of exercise is a focus of interest in both human and equine athletes but remains a challenge because many athletes experience cardiac murmurs and exercise-induced arrhythmias that are clinically irrelevant. This review summarises the effects of exercise on cardiac remodelling in the horse and the potential effects on athletic performance and SCD. The use of biomarkers and their future potential in the management of athletic horses is also reviewed.

Assessing exercise cardiac reserve using real-time cardiovascular magnetic resonance

BACKGROUND

Exercise cardiovascular magnetic resonance (ExCMR) has great potential for clinical use but its development has been limited by a lack of compatible equipment and robust real-time imaging techniques. We developed an exCMR protocol using an in-scanner cycle ergometer and assessed its performance in differentiating athletes from non-athletes.

METHODS

Free-breathing real-time CMR (1.5T Aera, Siemens) was performed in 11 athletes (5 males; median age 29 [IQR: 28-39] years) and 16 age- and sex-matched healthy volunteers (7 males; median age 26 [interquartile range (IQR): 25-33] years). All participants underwent an in-scanner exercise protocol on a CMR compatible cycle ergometer (Lode BV, the Netherlands), with an initial workload of 25W followed by 25W-increment every minute. In 20 individuals, exercise capacity was also evaluated by cardiopulmonary exercise test (CPET). Scan-rescan reproducibility was assessed in 10 individuals, at least 7 days apart.

RESULTS

The exCMR protocol demonstrated excellent scan-rescan (cardiac index (CI): 0.2 ± 0.5L/min/m²) and inter-observer (ventricular volumes: 1.2 ± 5.3mL) reproducibility. CI derived from exCMR and CPET had excellent correlation (r = 0.83, p < 0.001) and agreement (1.7 ± 1.8L/min/m²). Despite similar values at rest (P = 0.87), athletes had increased exercise CI compared to healthy individuals (at peak exercise: 12.2 [IQR: 10.2-13.5] L/min/m² versus 8.9 [IQR: 7.5-10.1] L/min/m², respectively; P < 0.001). Peak exercise CI, where image acquisition lasted 13-17 s, outperformed that at rest (c-statistics = 0.95 [95% confidence interval: 0.87-1.00] versus 0.48 [95% confidence interval: 0.23-0.72], respectively; P < 0.0001 for comparison) in differentiating athletes from healthy volunteers; and had similar performance as VO_2max (c-statistics = 0.84 [95% confidence interval = 0.62-1.00]; P = 0.29 for comparison).

CONCLUSIONS

We have developed a novel in-scanner exCMR protocol using real-time CMR that is highly reproducible. It may now be developed for clinical use for physiological studies of the heart and circulation.

Assessing exercise cardiac reserve using real-time cardiovascular magnetic resonance

BACKGROUND

Exercise cardiovascular magnetic resonance (ExCMR) has great potential for clinical use but its development has been limited by a lack of compatible equipment and robust real-time imaging techniques. We developed an exCMR protocol using an in-scanner cycle ergometer and assessed its performance in differentiating athletes from non-athletes.

METHODS

Free-breathing real-time CMR (1.5T Aera, Siemens) was performed in 11 athletes (5 males; median age 29 [IQR: 28-39] years) and 16 age- and sex-matched healthy volunteers (7 males; median age 26 [interquartile range (IQR): 25-33] years). All participants underwent an in-scanner exercise protocol on a CMR compatible cycle ergometer (Lode BV, the Netherlands), with an initial workload of 25W followed by 25W-increment every minute. In 20 individuals, exercise capacity was also evaluated by cardiopulmonary exercise test (CPET). Scan-rescan reproducibility was assessed in 10 individuals, at least 7 days apart.

RESULTS

The exCMR protocol demonstrated excellent scan-rescan (cardiac index (CI): 0.2 ± 0.5L/min/m2) and inter-observer (ventricular volumes: 1.2 ± 5.3mL) reproducibility. CI derived from exCMR and CPET had excellent correlation (r = 0.83, p < 0.001) and agreement (1.7 ± 1.8L/min/m2). Despite similar values at rest (P = 0.87), athletes had increased exercise CI compared to healthy individuals (at peak exercise: 12.2 [IQR: 10.2-13.5] L/min/m2 versus 8.9 [IQR: 7.5-10.1] L/min/m2, respectively; P < 0.001). Peak exercise CI, where image acquisition lasted 13-17 s, outperformed that at rest (c-statistics = 0.95 [95% confidence interval: 0.87-1.00] versus 0.48 [95% confidence interval: 0.23-0.72], respectively; P < 0.0001 for comparison) in differentiating athletes from healthy volunteers; and had similar performance as VO2max (c-statistics = 0.84 [95% confidence interval = 0.62-1.00]; P = 0.29 for comparison).

CONCLUSIONS

We have developed a novel in-scanner exCMR protocol using real-time CMR that is highly reproducible. It may now be developed for clinical use for physiological studies of the heart and circulation.

RV Remodeling in Olympic Athletes

OBJECTIVES

The aim of this study was to assess the impact of sex and different sports on right ventricular (RV) remodeling and compare the derived upper limits with widely used revised Task Force (TF) reference values.

BACKGROUND

Uncertainties exist regarding the extent and physiological determinants of RV remodeling in highly trained athletes. The issue is important, considering that in athletes RV size occasionally exceeds the cutoff limits proposed to diagnose arrhythmogenic RV cardiomyopathy.

METHODS

A total of 1,009 Olympic athletes (mean age 24 ± 6 years; n = 647 [64%] males) participating in skill, power, mixed, and endurance sport were evaluated by 2-dimensional echocardiography and Doppler/tissue Doppler imaging. The right ventricular outflow tract (RVOT) in parasternal long-axis (PLAX) and short-axis views, fractional area change, s' velocity, and morphological features were assessed.

RESULTS

Indexed RVOT PLAX was greater in females than in males (15.3 ± 2.2 mm/m² vs. 14.4 ± 1.9 mm/m²; p < 0.001). Both RVOT PLAX and parasternal short-axis view were significantly different among skill, power, mixed, and endurance sports: 14.3 ± 2.1 mm/m² versus 14.7 ± 1.9 mm/m² versus 14.0 ± 1.8 mm/m² versus 15.7 ± 2.2 mm/m², respectively (p < 0.001); and 15.2 ± 2.7 mm/m² versus 15.3 ± 2.4 mm/m² versus 14.8 ± 2.1 mm/m² versus 16.2 ± 2.5 mm/m², respectively (p < 0.001). The 95th percentile for indexed RVOT PLAX and parasternal short-axis view was 18 mm/m² and 20 mm/m², respectively. Fractional area change and s' velocity did not differ among the groups (p = 0.34 for both). RV enlargement compatible with major and minor TF diagnostic criteria for arrhythmogenic RV cardiomyopathy was observed in 41 (4%) and 319 (32%) athletes. A rounded apex was described in 823 (81%) athletes, prominent trabeculations in 378 (37%) athletes, and a prominent/hyperreflective moderator band in 5 (0.5%) athletes.

CONCLUSIONS

RV remodeling occurs in Olympic athletes, with male sex and endurance practice playing the major impact. A significant subset (up to 32%) of athletes exceeds the normal TF limits; therefore, we recommend referring to the 95th percentiles here reported as referral values; alternatively, only major diagnostic TF criteria for arrhythmogenic RV cardiomyopathy may be appropriate.

Right Ventricular Adaptation Is Associated with the Glu298Asp Variant of the NOS3 Gene in Elite Athletes

Nitric oxide (NO), an important endogenous pulmonary vasodilator is synthetized by the endothelial NO synthase (NOS3). Reduced NO bioavailability and thus the Glu298Asp polymorphism of NOS3 may enhance right ventricular (RV) afterload and hypertrophic remodeling and influence athletic performance. To test this hypothesis world class level athletes (water polo players, kayakers, canoeists, rowers, swimmers, n = 126) with a VO2 maximum greater than 50ml/kg/min were compared with non-athletic volunteers (n = 155). Cardiopulmonary exercise tests and cardiac magnetic resonance imaging (cMRI) were performed to determine structural or functional changes. Genotype distribution of the NOS3 Glu298Asp polymorphism was not affected by gender or physical performance. Cardiac MRI showed increased stroke volume with eccentric hypertrophy in all athletes regardless of their genotype. However, the Asp allelic variant carriers had increased RV mass index (32±6g versus 27±6g, p<0.01) and larger RV stroke volume index (71±10ml versus 64±10ml, p<0.01) than athletes with a Glu/Glu genotype. Genotype was not significantly associated with athletic performance. In the non-athletic group no genotype related differences were detected. The association between the NOS3 Glu298Asp polymorphism and RV structure and dimension in elite athletes emphasizes the importance of NOS3 gene function and NO bioavailability in sport related cardiac adaptation.