Comparison of frequency of significant electrocardiographic abnormalities in endurance versus nonendurance athletes

Electrocardiographic manifestations in female team handball players: analyzing ECG changes in athletes

Introduction

Long-term intense training leads to structural, functional, and electrical remodeling of the heart. How different sports affect the heart has not been fully investigated, particularly for female athletes. The aim of the present study was to investigate the morphology of 12-lead resting electrocardiogram (ECG) in elite female handball players compared to non-athlete female subjects. Potential changes will be explored to see if they could be explained by differences in cardiac dimensions and exercise hours.

Materials and methods

A cross-sectional study of 33 elite female team handball players compared to 33 sex and age-matched, non-athletic controls (age range 18-26 years) was performed. All participants underwent a resting 12-lead ECG and an echocardiographic examination. ECG variables for left ventricular hypertrophy and durations were evaluated and adjusted for cardiac dimensions and exercise hours using ANCOVA analysis. A linear regression analysis was used to describe relation between echocardiographic and ECG measures and exercise hours.

Results

The female handball players had larger cardiac dimensions and significantly lower heart rate and QTc duration (Bazett's formula) as well as increased QRS and QT durations compared to controls. The 12-lead sum of voltage and the 12-lead sum of voltage ∗ QRS were significantly higher among handball players. Changes in ECG variables reflecting the left ventricle could in part be explained by left ventricular size and exercise hours. Correlation with exercise hours were moderately strong in most of the echocardiographic measures reflecting left ventricular (LV), left ventricular mass (LVM), left atrium (LA) and right atrium (RA) size. Poor to fair correlations were seen in the majority of ECG measures.

Conclusions

Female team handball players had altered ECGs, longer QRS and QT durations, higher 12-lead sum of voltage and 12-lead sum of voltage ∗ QRS as well as shorter QTc (Bazett's formula) duration compared to non-athletic controls. These findings could only partly be explained by differences in left ventricular size. Despite larger atrial size in the athletes, no differences in P-wave amplitude and duration were found on ECG. This suggest that both structural, and to some degree electrical remodeling, occur in the female team handball players' heart and highlight that a normal ECG does not rule out structural adaptations. The present study adds knowledge to the field of sports cardiology regarding how the heart in female team handball players adapts to this type of sport.

ECG findings in professional rugby players using international screening recommendations

Background

While World Rugby guidelines do not mandate the inclusion of an electrocardiogram (ECG) for all players, this is required for entry into international rugby competitions. We, therefore, sought to describe sport-specific normative ECG values and evaluate the performance of contemporary athlete ECG guidelines in male and female professional rugby players.

Methods

We retrospectively analysed professional rugby players' ECGs (n=356, male 79%) obtained during preparticipation screening (2010-2022), comparing by sex and playing position (forwards vs backs). ECGs were categorised as normal 'training-related', borderline and abnormal findings, as defined by the 2017 International Recommendations.

Results

84% of players had one or more normal, 'training-related' findings, with males having a higher prevalence than females (91% vs 60%, p<0.001). Most ECG findings did not vary by position. No female player had borderline or abnormal ECG findings. Borderline findings were present in 3% (n=12/356) of players. Abnormal findings were present in 2% (n=7/356) of players. Overall, 2.2% of ECGs were 'positive' (n=8/356, including n=1 ECG with two borderline findings).

Conclusions

The application of contemporary ECG interpretation criteria resulted in a low positivity rate isolated to male players. These results help inform the logistic feasibility of ECG-inclusive screening, which is already required to enter major tournaments.

Sudden cardiac arrest in athletes and strategies to optimize preparedness

Sudden cardiac arrest (SCA) is the leading cause of death in young athletes. Despite efforts to improve preparedness for cardiac emergencies, the incidence of out-of-hospital cardiac arrests in athletes remains high, and bystander awareness and readiness for SCA support are inadequate. Initiatives such as designing an emergency action plan (EAP) and mandating training in cardiopulmonary resuscitation (CPR) and automated external defibrillator use (AED) for team members and personnel can contribute to improved survival rates in SCA cases. This review provides an overview of SCA in athletes, focusing on identifying populations at the highest risk and evaluating the effectiveness of different screening practices in detecting conditions that may lead to SCA. We summarize current practices and recommendations for improving the response to SCA events, and we highlight the need for ongoing efforts to optimize preparedness through the implementation of EAPs and the training of individuals in CPR and AED use. Additionally, we propose a call to action to increase awareness and training in EAP development, CPR, and AED use for team members and personnel. To improve outcomes of SCA cases in athletes, it is crucial to enhance bystander awareness and preparedness for cardiac emergencies. Implementing EAPs and providing training in CPR and AED use for team members and personnel are essential steps toward improving survival rates in SCA cases.

Outcomes of Investigating T Wave Inversion With Echocardiography in an Unselected Young Male Preparticipation Cohort

BACKGROUND Electrocardiography (ECG) may be performed as part of preparticipation sports screening. Recommendations on screening of athletes to identify individuals with previously unrecognized cardiac disease are robust; however, data guiding the preparticipation screening of unselected populations are scarce. T wave inversion (TWI) on ECG may suggest an undiagnosed cardiomyopathy. This study aims to describe the prevalence of abnormal TWI in an unselected young male cohort and the outcomes of an echocardiography-guided approach to investigating these individuals for structural heart diseases, focusing on the yield for cardiomyopathies. METHODS AND RESULTS Consecutive young male individuals undergoing a national preparticipation cardiac screening program for 39 months were studied. All underwent resting supine 12-lead ECG. Those manifesting abnormal TWI, defined as negatively deflected T waves of at least 0.1 mV amplitude in any 2 contiguous leads, underwent echocardiography. A total of 69 714 male individuals with a mean age of 17.9±1.1 years were studied. Of the individuals, 562 (0.8%) displayed abnormal TWI. This was most frequently observed in the anterior territory and least so in the lateral territory. A total of 12 individuals (2.1%) were diagnosed with a cardiomyopathy. Cardiomyopathy diagnoses were significantly associated with deeper maximum TWI depth and the presence of abnormal TWI in the lateral territory, but not with abnormal TWI in the anterior and inferior territories. No individual presenting with TWI restricted to solely leads V1 to V2, 2 inferior leads or both was diagnosed with a cardiomyopathy. CONCLUSIONS Cardiomyopathy diagnoses were more strongly associated with certain patterns of abnormal TWI. Our findings may support decisions to prioritize echocardiography in these individuals.

The Athlete's Heart-Challenges and Controversies: JACC Focus Seminar 4/4

Regular exercise promotes structural, functional, and electrical remodeling of the heart, often referred to as the "athlete's heart," with intense endurance sports being associated with the greatest degree of cardiac remodeling. However, the extremes of exercise-induced cardiac remodeling are potentially associated with uncommon side effects. Atrial fibrillation is more common among endurance athletes and there is speculation that other arrhythmias may also be more prevalent. It is yet to be determined whether this arrhythmic susceptibility is a result of extreme exercise remodeling, genetic predisposition, or other factors. Gender may have the greatest influence on the cardiac response to exercise, but there has been far too little research directed at understanding differences in the sportsman's vs sportswoman's heart. Here in part 4 of a 4-part seminar series, the controversies and ambiguities regarding the athlete's heart, and in particular, its arrhythmic predisposition, genetic, and gender influences are reviewed in depth.

Electrocardiographic Findings in Professional Male Athletes

OBJECTIVE

To generate granular normative electrocardiogram (ECG) data and characterize the variation by ethnicity and sport played.

DESIGN

Cross-sectional study; ECGs were collected from preseason screening programs from 2012 to 2019 and interpreted in accordance with athlete-specific guidelines.

SETTING

Of the professional athletes based in Vancouver, the North Shore Heart Centre performs the annual preparticipation ECG screening.

PARTICIPANTS

Seven hundred fifty-three professional male athletes competing in hockey, football, lacrosse, skiing, and snowboarding.

INTERVENTIONS

Independent variables include commonly transcribed electrocardiographic findings, for example, those indicating benign and pathologic findings.

MAIN OUTCOME MEASURES

Prevalence of and variance in electrocardiographic findings by sport played and ethnicity.

RESULTS

Of the 753 athletes, 171 (22.3%) were National Hockey League, 358 (47.5%) were Canadian Football League, 163 (21.6%) were Major League Soccer and/or the Canadian National Soccer team, and 61 (8%) others. The most common finding, sinus bradycardia, was more likely in both soccer (P < 0.001) and hockey (P < 0.001) versus football players. Early repolarization (ER) was more likely in soccer players versus both hockey (P < 0.001) and football players (P = 0.001). Within football, Black athletes (BA) were more likely than White athletes to display ER (P = 0.009), left ventricular hypertrophy (P = 0.004), and nonspecific ST changes (P = 0.027).

CONCLUSION

Our study contributes to the generation of normative data for ECG findings while accounting for ethnic and sport-specific variation. The expected clinical presentation of endurance athletes, including soccer players, and the possible predisposition of BA to develop distinct adaptations can augment clinical care by delineating physiology from pathologic changes.

Low Risk of Cardiac Complications in Collegiate Athletes After Asymptomatic or Mild COVID-19 Infection

OBJECTIVE

The objective of this study was to determine the utility of "standard" cardiac screening with EKG, echocardiography, and serum troponin T (hs-Tn T) testing after COVID infection in competitive college athletes.

DESIGN

Prospective cohort study.

SETTING

Tertiary cardiology clinic, university training room.

PARTICIPANTS

Sixty-five Division 1 athletes recovered from COVID-19 and 465 controls.

ASSESSMENT

All COVID-recovered athletes underwent cardiac screening on return to campus in fall 2020. Controls were screened if indicated by preparticipation examination. Students cleared for sports participation were followed for the development of cardiac complications.

MAIN OUTCOME MEASURE

Incidence of cardiac complications after COVID infection.

RESULTS

Infected athletes experienced mild (26/65), moderate (8/65), or no (31/65) COVID symptoms. No athletes had severe symptoms. Men were more likely to have been asymptomatic (20/31), and women were more likely to have had moderate (7/8) symptoms (P = 0.015). All athletes, except 2 with anosmia, were asymptomatic at the time of cardiac testing. One athlete had persistently elevated hs-Tn T but no evidence of myocarditis on cardiac MRI. All other cardiac testing was negative. No athletes were diagnosed with myocarditis (95% CI: 0%-5.5%). All athletes were cleared for athletic participation. None suffered complications over the next 9 months.

CONCLUSIONS

After COVID-19 infection, no college athletes with mild, moderate, or no symptoms had signs of myocarditis, and all returned to play without cardiac complication. These findings support consensus opinion recommendations that college-age athletes who recovered from COVID-19 and who experienced mild or no symptoms may return to play without cardiac testing.

Electrocardiographic characteristics of trained and untrained standardbred racehorses

Background

Long‐term exercise induces cardiac remodeling that potentially influences the electrical properties of the heart.

Hypothesis/objectives

We assessed whether training alters cardiac conduction in Standardbred racehorses.

Animals

Two hundred one trained and 52 untrained Standardbred horses.

Methods

Cross‐sectional study. Resting ECG recordings were analyzed to assess heart rate (HR) along with standard ECG parameters and for identification of atrial and ventricular arrhythmias. An electrophysiological study was performed in 13 horses assessing the effect of training on sinoatrial (SA) and atrioventricular (AV) nodal function by sinus node recovery time (SNRT) and His signal recordings. Age and sex adjustments were implemented in multiple and logistic regression models for comparison.

Results

Resting HR in beats per minute (bpm) was lower in trained vs untrained horses (mean, 30.8 ± 2.6 bpm vs 32.9 ± 4.2 bpm; P = .001). Trained horses more often displayed second‐degree atrioventricular block (2AVB; odds ratio, 2.59; P = .04). No difference in SNRT was found between groups (n = 13). Mean P‐A, A‐H, and H‐V intervals were 71 ± 20, 209 ± 41, and 134 ± 41 ms, respectively (n = 7). We did not detect a training effect on AV‐nodal conduction intervals. His signals were present in 1 horse during 2AVB with varying H‐V interval preceding a blocked beat.

Conclusions and Clinical Importance

We identified decreased HR and increased frequency of 2AVB in trained horses. In 5 of 7 horses, His signal recordings had variable H‐V intervals within each individual horse, providing novel insight into AV conduction in horses.

Exercise and the Female Heart

Female participation in sport has increased sharply during the last few decades, and for the third straight Olympic Games, there were more women than men on the US roster for the 2020 Tokyo Games. Given this, an understanding of the differences between men and women with respect to exercise-induced cardiac remodeling is critical for those caring for female athletes. Recent studies have provided insight into female-specific cardiac remodeling and have enhanced our understanding on the upper limits of cardiac remodeling in female athletes and how these adaptations compare with sedentary females, male athletes, and cardiomyopathies. Female athletes display fewer signs of adaptive remodeling on ECG compared with male athletes. Structurally, male athletes have larger absolute cardiac dimensions, but female athletes have similar or larger chamber size when adjusted for body size. Female athletes have a lower incidence of sudden cardiac arrest or death compared with male athletes in the early competitive years (high school, college, and professional) and in the masters athlete years. In addition, female athletes are less likely to have coronary disease and atrial fibrillation compared with male athletes. Data on longevity indicate that female athletes live longer than their sedentary counterparts. Unlike men, there has been no convincing association of extreme exercise and cardiovascular disease in longer-term endurance female athletes. The underlying mechanisms of these sex-based differences are not very well understood, and future studies are warranted to better understand the mechanisms of cardiac adaptation in female athletes.

The 12-lead electrocardiogram of the elite female footballer as defined by different interpretation criteria across the competitive season

ABSTRACTPre-participation screening (PPS), using a 12-lead electrocardiogram (ECG), is recommended to identify athletes at risk of sudden cardiac death (SCD). ECG interpretation criteria have been developed to address the concern arising from high false-positives in athletes. There are limited ECG data in elite female footballers. The aims of this study were to (1) compare the ECG outcomes using three published ECG criteria (European Society of Cardiology [ESC], Seattle, International) in elite female footballers and (2) compare ECG data at three different stages of a competitive season. Eighty-one elite female footballers (21 ± 4 yr) completed a medical assessment, anthropometrics, resting blood pressure and a resting 12-lead ECG. Each 12-lead ECG was interpreted in accordance with (1) ESC; (2) Seattle; (3) International Criteria to determine training-related and non-training-related ECG changes. A subset of thirteen (26 ± 4 yr) footballers had repeated resting ECG tests at three time points across the competitive season. Eighty percent of females had training-related ECG patterns. Sinus bradycardia (65%) and early repolarization (42%) were the most common. Using the ESC Criteria 25% (20/81) of the athletes were considered to have an abnormal ECG, compared to 0% using the Seattle and International Criteria, mainly due to alterations in QT length criteria. There were no clinically significant differences in ECG data across a competitive season. The Seattle and International ECG Criteria significantly reduced the number of ECG false-positives in elite female footballers and the time point of PPS within a competitive season is unlikely to alter the PPS outcomes.Abbreviations: AMSSM: American Medical Society for Sports Medicine; ANOVA: Analysis of Variance; BSA: Body Surface Area; ECG: Electrocardiogram; ESC: European Society of Cardiology; FA: Football Association; FIFA: The Fédération Internationale de Football Association (FIFA); F-MARC: FIFA Medical Assessment and Research Centre; LAE: Left atrial enlargement; LVH: Left ventricular hypertrophy; PPS: Pre-participation screening; SCD: Sudden cardiac death.

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.

Prevention of Pathological Atrial Remodeling and Atrial Fibrillation: JACC State-of-the-Art Review

Atrial enlargement in response to pathological stimuli (e.g., hypertension, mitral valve disease) and physiological stimuli (exercise, pregnancy) can be comparable in magnitude, but the diseased enlarged atria is associated with complications such as atrial fibrillation (AF), whereas physiological atrial enlargement is not. Pathological atrial enlargement and AF is also observed in a small percentage of athletes undergoing extreme/intense endurance sport and pregnant women with preeclampsia. Differences between physiological and pathological atrial enlargement and underlying mechanisms are poorly understood. This review describes human and animal studies characterizing atrial enlargement under physiological and pathological conditions and highlights key knowledge gaps and clinical challenges, including: 1) the limited ability of atria to reverse remodel; and 2) distinguishing physiological and pathological enlargement via imaging/biomarkers. Finally, this review discusses how targeting distinct molecular mechanisms underlying physiological and pathological atrial enlargement could provide new therapeutic and diagnostic strategies for preventing or reversing atrial enlargement and AF.

Exercise Preconditioning Promotes Autophagy to Cooperate for Cardioprotection by Increasing LC3 Lipidation-Associated Proteins

The cardioprotection of exercise preconditioning (EP) has been well documented. EP can be divided into two phases that are the induction of exercise preconditioning (IEP) and the protection of exercise preconditioning (PEP). PEP is characterized by biphasic protection, including early exercise preconditioning (EEP) and late exercise preconditioning (LEP). LC3 lipidation-mediated autophagy plays a pivotal role in cardioprotection. This study aimed to investigate the alterations of LC3 lipidation-associated proteins during EP-induced cardioprotection against myocardial injury induced by exhaustive exercise (EE) was used in a rat model of EP. These rats were subjected to an intermittent exercise consisting of four periods, with each period including 10 min of running at 30 m/min and 0% grade (approximately 75% VO_2max) followed by 10 min of intermittent rest. A model of EE-induced myocardial injury was developed by subjecting rats to a consecutive running (30 m/min, 0% grade) till exhaustion. Following EEP, the colocalization of LC3 with Atg7 was significantly increased, and LC3-I, LC3-II, LC3-II/LC3-I, Atg7, Atg4B, and Atg3 levels were significantly increased. Atg7, Atg4B, and Atg3 mRNAs were all significantly upregulated, and LC3 mRNAs tended to be higher. Following LEP, Atg4B, and Atg3 levels were significantly increased. Atg7, Atg4B, and Atg3 mRNAs were all significantly upregulated, and LC3 mRNAs tended to be higher. A group of rats were subjected to EEP followed by EE, and the co-localization of LC3 with Atg7 was significantly increased, while LC3-I, LC3-II, LC3-II/LC3-I, Atg7, Atg4B, and Atg3 levels were also significantly increased. Moreover, there was a significant increase in the co-localization of LC3 with Atg7, LC3-I, LC3-II, Atg7, and Atg4B levels during LEP followed by EE. The formation of autophagosome during LEP followed by EE may have been weaker than that during EEP followed by EE due to the lower lipidation of LC3. EP may promote autophagy to maintain cell homeostasis and survival, which cooperates for cardioprotection of alleviating exhaustive exercise-induced myocardial injury by increasing LC3 lipidation-associated proteins. There is a difference between EEP and LEP in terms of the mechanisms of cardioprotection afforded by these respective conditions. The positive regulation of transcription and translation level of LC3 lipidation-associated proteins may all be involved in the mechanism of EEP and LEP, while compared with LEP, the regulation of translation level of EEP is more positively to promote autophagy.

Impact of early sports specialisation on paediatric ECG

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

Electrocardiographic interpretation in athletes

Participation in regular exercise of moderate intensity is associated with a plethora of systemic benefits, including a reduction in risk factors for coronary atherosclerosis; however, intensive exercise may paradoxically culminate in sudden cardiac arrest among individuals harboring arrhythmogenic substrates. The precise mechanism for arrhythmogenesis is likely multifactorial, however, surges in catecholamines, electrolyte shifts, acid-base disturbances, increased core temperature and demand myocardial ischemia are potential contributors. Although most deaths occur in middle aged and older males with atherosclerotic coronary artery disease, a significant proportion also affect young athletes with inherited or congenital cardiac abnormalities. The impact of such catastrophes on society, particularly when a young high-profile athlete is affected could be considered a justified reason for identifying individuals who may be at risk. Given the rarity of deaths in young athletes, only the simplest screening test, such as the 12-lead electrocardiography (ECG) may be considered to be cost effective. The ECG is effective for detecting serious electrical diseases in young athletes such as congenital electrical accessory pathways and ion channel diseases but can also identify athletes with potential life-threatening structural diseases such as hypertrophic and arrhythmogenic cardiomyopathy. One of the concerns about ECG screening is that regular intensive exercise results in several physiological alterations in cardiac structure and function that are reflected on the athlete's ECG. Sinus bradycardia, first-degree atrioventricular block, incomplete right bundle branch block, minor J-point elevation and large QRS voltages are common. Conversely, some repolarization anomalies affecting the ST segment, T waves and QT interval may overlap with patterns observed in patients with serious cardiac diseases. The situation is complicated further because age, sex and ethnicity of the athletes also influence the ECG and there is a risk that erroneous interpretation could have serious consequences. This review will describe the normal electrical patterns of the "athlete's heart" and provide insights into differentiation physiological electrical patterns from those observed in serious cardiac disease.

Criteria for interpretation of the athlete's ECG: A critical appraisal

The electrocardiogram (ECG) is cheap and widely available but its use as a screening tool for early identification of athletes with a cardiac disease at risk of sudden cardiac death is controversial because of presumed low specificity. In the last decade, several efforts have been made to improve the distinction between physiological and pathological ECG findings in the athlete, leading to continuous evolution of the interpretation criteria. The most recent 2017 International criteria grouped ECG changes into three categories: normal, borderline, and abnormal. Borderline findings warrant further investigations only when two or more are present while abnormal changes should always be considered as the sign of a possible underlying disease. This review encompasses the evolution of the athlete's ECG interpretation criteria and highlights areas of uncertainty that will need to be addressed by further studies.

Interpretation of T-wave inversion in physiological and pathological conditions: Current state and future perspectives

The presence of T‐wave inversion (TWI) at 12‐lead electrocardiogram (ECG) in competitive athletes is one of the major diagnostic challenges for sports physicians and consulting cardiologists. Indeed, while the presence of TWI may be associated with some benign conditions and it may be occasionally seen in healthy athletes presenting signs of cardiac remodeling, it may also represent an early sign of an underlying, concealed structural heart disease or life‐threatening arrhythmogenic cardiomyopathies, which may be responsible for exercise‐related sudden cardiac death (SCD). The interpretation of TWI in athletes is complex and the inherent implications for the clinical practice represent a conundrum for physicians. Accordingly, the detection of TWI should be viewed as a potential red flag on the ECG of young and apparently healthy athletes and warrants further investigations because it may represent the initial expression of cardiomyopathies that may not be evident until many years later and that may ultimately be associated with adverse outcomes. The aim of this review is, therefore, to report an update of the literature on TWI in athletes, with a specific focus on the interpretation and management.

How to interpret right ventricular remodeling in athletes

Long-lasting athletic training induces an overload on the heart that leads to structural, functional, and electrical adaptive changes known as the "athlete's heart." The amount of this heart remodeling has been traditionally considered balanced between the left and the right heart chambers. However, during intense exercise, the right heart is exposed to a disproportional afterload and wall stress which over a long period of time could lead to more pronounced exercise-induced changes. Highly trained athletes, especially those involved in endurance sport disciplines, can develop marked right ventricular (RV) remodeling that could raise the suspicion of an underlying RV pathology including arrhythmogenic cardiomyopathy (ACM). The distinction between physiological and pathological RV remodeling is essential as ACM is a common cause of sudden cardiac death in athletes, and high-intensity exercise training has demonstrated to accelerate its phenotypic expression and worsen its prognosis. The distinction between physiological and pathological RV remodeling is essential since ACM is a common cause of sudden cardiac death in athletes, and high-intensity exercise training has demonstrated to accelerate the phenotypic expression and worsen the prognosis. This article outlines the physiological adaptation of the RV to acute exercise, the subsequent physiological structural and functional changes induced by athletic training and provides useful tips of how to differentiate between physiological RV remodeling and a cardiomyopathy phenotype.

Exercise and Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a group of cardiomyopathies associated with ventricular arrhythmias predominantly arising from the right ventricle, sudden cardiac death and right ventricular failure, caused largely due to inherited mutations in proteins of the desmosomal complex. Whilst long recognised as a cause of sudden cardiac death (SCD) during exercise, it has recently been recognised that intense and prolonged exercise can worsen the disease resulting in earlier and more severe phenotypic expression. Changes in cardiac structure and function as a result of exercise training also pose challenges with diagnosis as enlargement of the right ventricle is commonly seen in endurance athletes. Advice regarding restriction of exercise is an important part of patient management, not only of those with established disease, but also in individuals known to carry gene mutations associated with development of ARVC.

Abnormal ECG Findings in Athletes: Clinical Evaluation and Considerations

PURPOSE OF REVIEW

Pre-participation cardiovascular evaluation with electrocardiography is normal practice for most sporting bodies. Awareness about sudden cardiac death in athletes and recognizing how screening can help identify vulnerable athletes have empowered different sporting disciplines to invest in the wellbeing of their athletes.

RECENT FINDINGS

Discerning physiological electrical alterations due to athletic training from those representing cardiac pathology may be challenging. The mode of investigation of affected athletes is dependent on the electrical anomaly and the disease(s) in question. This review will highlight specific pathological ECG patterns that warrant assessment and surveillance, together with an in-depth review of the recommended algorithm for evaluation.

International recommendations for electrocardiographic interpretation in athletes

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

Interpreting the Athlete's ECG: Current State and Future Perspectives

Sudden cardiac death (SCD) is the leading cause of death in athletes. A large proportion of these deaths are associated with undiagnosed cardiovascular disease. Screening for high-risk individuals enables early detection of pathology, as well as permitting lifestyle modification or therapeutic intervention.ECG changes in athletes occur as a result of electrical and structural adaptations secondary to repeated bouts of exercise. Such changes are common and may overlap with patterns suggestive of underlying cardiovascular disease. Correct interpretation is therefore essential, in order to differentiate physiology from pathology. Erroneous interpretation may result in false reassurance or expensive investigations for further evaluation and unnecessary disqualification from competitive sports.Interpretation of the athlete's ECG has evolved over the past 12 years, beginning with the 2005 European Society of Cardiology (ESC) consensus, progressing to the ESC recommendations (2010), Seattle Criteria (2013) and the 'refined' criteria (2014). This evolution culminated in the recently published international recommendations for ECG interpretation in athletes (2017), which has led to a significant reduction in false positives and screening-associated costs. This review aims to describe the evolution of the current knowledge on ECG interpretation as well as future directions.

The early repolarization pattern: Echocardiographic characteristics in elite athletes

BACKGROUND

The electrocardiographic early repolarization (ER) pattern is associated with idiopathic ventricular fibrillation and increased long-term cardiovascular mortality. Whether structural cardiac aberrations influence the phenotype is unclear. Since ER is particularly common in athletes, we evaluated its prevalence and investigated predisposing echocardiographic characteristics and cardiopulmonary exercise capacity in a cohort of elite athletes.

METHODS

A total of 623 elite athletes (age 21 ± 5 years) were examined during annual preparticipation screening from 2006 until 2012 including electrocardiography, echocardiography, and exercise testing. ECGs were analyzed with focus on ER. All athletes participated in a clinical follow-up.

RESULTS

The prevalence of ER was 17% (108/623). ER-positive athletes were predominantly male (71%, 77/108), showed a lower heart rate (57.1 ± 9.3 bpm versus 60.0 ± 11.2 bpm; p = 0.015) and a higher lean body mass compared to ER-negative participants (88.1% ± 5.6% versus 86.5% ± 6.3%; p = 0.015). Echocardiographic measurements and cardiopulmonary exercise capacity in male and female athletes with and without ER largely showed similar results. Only the notching ER subtype (n = 15) was associated with an increased left atrial diameter (OR 7.01, 95%CI 1.65-29.83; p = 0.008), a higher left ventricular mass (OR 1.02, 95%CI 1.00-1.03; p = 0.038) and larger relative heart volume (OR 1.01, 95%CI 1.00-1.01; p = 0.01). During a follow-up of 7.4 ± 1.5 years, no severe cardiovascular event occurred in the study sample.

CONCLUSIONS

In elite athletes presence of ER is not associated with distinct alterations in echocardiography and cardiopulmonary exercise. Athletes presenting with ER are rather male, lean with a low heart rate.

A 48-Year-Old Athletic Man With Bradycardia During Sleep

CASE PRESENTATION

A 48-year-old athletic man with history of dyslipidemia and second-degree atrioventricular block (Mobitz type I 2:1 atrioventricular block) endorses sleep-related difficulties at his annual physical examination. Mobitz type I block was diagnosed 11 years earlier when the patient presented to his primary care physician with left-sided chest pain for 2 months. He was evaluated by cardiology, with a normal stress echocardiogram. The impression was that the chest pain was nonanginal. He describes sleeping for only a few hours at a time and has nighttime awakenings. He does not wake up feeling refreshed. He experiences passive daytime sleepiness and evening somnolence. He is very active, runs every day, and has participated in several half-marathons. He currently undergoes high-intensity interval training, including running and lifting. Per his wife, the patient snores loudly and has apneic episodes during sleep. One of his siblings has OSA. He denies excessive sleepiness, with an Epworth Sleepiness Scale score of 2.

Prevalence and significance of notched T-waves in elite professional cyclists

OBJECTIVES

To identify the frequency and significance of notched T-waves (NTW) in elite endurance athletes.

METHODS

Professional cyclists were followed for 4 years with a clinical, electrocardiographic and echocardiographic assessment. Electrocardiograms were classified according to the presence or absence of NTWs; clinical and echocardiographic correlates were assessed.

RESULTS

42 Caucasian male cyclists were included. NTW were detected in 8 (19%) cyclists who showed significantly longer QT (461 ± 15 vs 422 ± 33 ms, p < 0.01) and QTc intervals (434 ± 19 vs 383 ± 21 ms, p < 0.01), a larger left ventricular end-diastolic volume (163 ± 27 vs 137 ± 23 mL, p = 0.014), end-diastolic volume index (84 ± 13 vs 73 ± 11 mL, p = 0.037) and end-diastolic apex-to-base length (9.9 ± 0.7 vs 9.3 ± 0.5 mm. p = 0.035). There were no detected arrhythmic events, and echocardiography did not reveal any abnormalities.

CONCLUSIONS

This is to our knowledge the first study reporting a high prevalence of NTW in athletes. In our small cohort of cyclists NTW were associated with QT interval prolongation and left ventricular changes. This may be indicative of underlying inhomogeneity of repolarisation. Expanding on this research could reveal a role for NTW in identifying ventricular morphological changes.

Cardiac Screening of Young Athletes: a Practical Approach to Sudden Cardiac Death Prevention

PURPOSE OF REVIEW

We aim to report on the current status of cardiovascular screening of athletes worldwide and review the up-to-date evidence for its efficacy in reducing sudden cardiac death in young athletes.

RECENT FINDINGS

A large proportion of sudden cardiac death in young individuals and athletes occurs during rest with sudden arrhythmic death syndrome being recognised as the leading cause. The international recommendations for ECG interpretation have reduced the false-positive ECG rate to 3% and reduced the cost of screening by 25% without compromising the sensitivity to identify serious disease. There are some quality control issues that have been recently identified including the necessity for further training to guide physicians involved in screening young athletes. Improvements in our understanding of young sudden cardiac death and ECG interpretation guideline modification to further differentiate physiological ECG patterns from those that may represent underlying disease have significantly improved the efficacy of screening to levels that may make screening more attractive and feasible to sporting organisations as a complementary strategy to increased availability of automated external defibrillators to reduce the overall burden of young sudden cardiac death.

Atrial remodeling and ectopic burden in recreational athletes: Implications for risk of atrial fibrillation

BACKGROUND

Atrial remodeling, vagal tone, and atrial ectopic triggers are suggested to contribute to increased incidence of atrial fibrillation (AF) in endurance athletes. How these parameters change with increased lifetime training hours is debated.

HYPOTHESIS

Atrial remodeling occurs in proportion to total training history, thus contributing to elevated risk of AF.

METHODS

We recruited 99 recreational endurance athletes, subsequently grouped according to lifetime training hours, to undergo evaluation of atrial size, autonomic modulation, and atrial ectopy. Athletes were grouped by self-reported lifetime training hours: low (<3000 h), medium (3000-6000 h), and high (>6000 h). Left atrial (LA) volume, left ventricular (LV) dimensions, and LV systolic and diastolic function were assessed by echocardiography. We used 48-hour ambulatory electrocardiographic monitoring to determine heart rate, heart rate variability, premature atrial contractions, and premature ventricular contractions.

RESULTS

LA volume was significantly greater in the high (+5.1 mL/m² , 95% CI: 1.3-8.9) and medium (+4.2 mL/m² , 95% CI: 0.2-8.1) groups, compared with the low group. LA dilation was observed in 19.4%, 12.9%, and 0% of the high, medium, and low groups, respectively (P = 0.05). No differences were observed between groups for measures of LV dimensions or function. Minimum heart rate, parasympathetic tone expressed using heart rate variability indices, and premature atrial contraction and premature ventricular contraction frequencies did not differ between groups.

CONCLUSIONS

In recreational endurance athletes, increased lifetime training is associated with LA dilation in the absence of increased vagal parameters or atrial ectopy, which may promote incidence of AF in this cohort.

Exercise and the right ventricle: a potential Achilles' heel

Exercise is associated with unequivocal health benefits and results in many structural and functional changes of the myocardium that enhance performance and prevent heart failure. However, intense exercise also presents a significant hemodynamic challenge in which the right-sided heart chambers are exposed to a disproportionate increase in afterload and wall stress that can manifest as myocardial fatigue or even damage if intense exercise is sustained for prolonged periods. This review focuses on the physiological factors that result in a disproportionate load on the right ventricle during exercise and the long-term consequences. The changes in cardiac structure and function that define 'athlete's heart' disproportionately affect the right-sided heart chambers and this can raise important diagnostic overlap with some cardiac pathologies, particularly some inherited cardiomyopathies. The interaction between exercise and arrhythmogenic right ventricular cardiomyopathy (ARVC) will be highlighted as an important example of how hemodynamic stressors can combine with deficiencies in cardiac structural elements to cause cardiac dysfunction predisposing to arrhythmias. The extent to which extreme exercise can cause adverse remodelling in the absence of a genetic predisposition remains controversial. In the athlete with profound changes in heart structure, it can be extremely challenging to determine whether common symptoms such as palpitations may be a marker of more sinister arrhythmias. This review discusses some of the techniques that have recently been proposed to identify pathology in these circumstances. Finally, we will discuss recent evidence defining the role of exercise restriction as a therapeutic intervention in individuals predisposed to arrhythmogenic cardiomyopathy.

Athlete's ECG - Simple Tips for Navigation

Regular exercise training results in structural and electrical cardiac adaptations which are reflected in the resting 12-lead electrocardiograph (ECG), thus an athlete's ECG can be quite different to that of a sedentary person of the same age, gender and ethnicity. This has been recognised as an issue in the setting of pre-participation ECG screening of athletes in whom false positive findings are commonplace when using normative ECG values derived from sedentary populations. As such, athlete ECG interpretation guidelines have been devised and modified several times over the past decade, with the ultimate goal of reducing the number of athletes undergoing unnecessary secondary investigations to exclude cardiac pathology whilst maintaining the sensitivity of the ECG in detecting cardiac diseases associated with sudden cardiac death (SCD). By no means exhaustive, the following series of athlete ECG examples is aimed at providing the reader with a basic understanding of what ECG changes are considered normal for an athlete, and what changes should prompt further investigation to exclude cardiac pathology, even in the absence of symptoms.

Differentiating Athlete's Heart From Cardiomyopathies - The Left Side

In athletes who undertake a high volume of high intensity exercise, the resultant changes in cardiac structure and function which develop as a result of physiological adaptation to exercise (so called "Athlete's Heart") may overlap with some features of pathological conditions. This chapter will focus on the left side of the heart, where left ventricular cavity enlargement, increase in left ventricular wall thickness and increased left ventricular trabeculation associated with athletic remodelling may sometimes be difficult to differentiate from conditions such as dilated cardiomyopathy, hypertrophic cardiomyopathy or isolated left ventricular non-compaction. The distinction between physiological versus pathological changes in athletes is imperative as an incorrect diagnosis can have important consequences, such as exclusion from competitive sport, or false reassurance and missed opportunity for effective therapeutic intervention.

Comments on the New International Criteria for Electrocardiographic Interpretation in Athletes

Sudden cardiac death is the most common medical cause of death during the practice of sports. Several structural and electrical cardiac conditions are associated with sudden cardiac death in athletes, most of them showing abnormal findings on resting electrocardiogram (ECG). However, because of the similarity between some ECG findings associated with physiological adaptations to exercise training and those of certain cardiac conditions, ECG interpretation in athletes is often challenging. Other factors related to ECG findings are race, age, sex, sports discipline, training intensity, and athletic background. Specific training and experience in ECG interpretation in athletes are therefore necessary. Since 2005, when the first recommendations of the European Society of Cardiology were published, growing scientific evidence has increased the specificity of ECG standards, thus lowering the false-positive rate while maintaining sensitivity. New international consensus guidelines have recently been published on ECG interpretation in athletes, which are the result of consensus among a group of experts in cardiology and sports medicine who gathered for the first time in February 2015 in Seattle, in the United States. The document is an important milestone because, in addition to updating the standards for ECG interpretation, it includes recommendations on appropriate assessment of athletes with abnormal ECG findings. The present article reports and discusses the most novel and relevant aspects of the new standards. Nevertheless, a complete reading of the original consensus document is highly recommended.

The Complex Phenotype of the Athlete's Heart: Implications for Preparticipation Screening

Preparticipation screening is vital to exclude inherited cardiac conditions that have the potential to cause sudden cardiac death in seemingly healthy athletes. Recent research has questioned traditional theories of load-induced, dichotomous cardiac adaptation. We therefore considered whether a one-size-fits-all approach to screening can account for interindividual differences brought about by sporting discipline, training volume, ethnicity, body size, sex, and age.

Impact of the dynamic and static component of the sport practised for electrocardiogram analysis in screening athletes

To interpret the electrocardiogram (ECG) of athletes, the recommendations of the ESC and the Seattle criteria define type 1 peculiarities, those induced by training, and type 2, those not induced by training, to rule out cardiomyopathy. The specificity of the screening was improved by Sheikh who defined "Refined Criteria," which includes a group of intermediate peculiarities. The aim of our study was to investigate the influence of static and dynamic components on the prevalence of different types of abnormalities. The ECGs of 1030 athletes performed during preparticipation screening were interpreted using these three classifications. Our work revealed 62/16%, 69/13%, and 71/7% of type 1 peculiarities and type 2 abnormalities for the ESC, Seattle, and Refined Criteria algorithms, respectively(P<.001). For type 2 abnormalities, three independent factors were found for the ESC and Seattle criteria: age, Afro-Caribbean origin, and the dynamic component with, for the latter, an OR[95% CI] of 2.35[1.28-4.33] (P=.006) and 1.90[1.03-3.51] (P=.041), respectively. In contrast, only the Afro-Caribbean origin was associated with type 2 abnormalities using the Refined Criteria: OR[95% CI] 2.67[1.60-4.46] (P<.0001). The Refined Criteria classified more athletes in the type 1 category and fewer in the type 2 category compared with the ESC and Seattle algorithms. Contrary to previous studies, a high dynamic component was not associated with type 2 abnormalities when the Refined Criteria were used; only the Afro-Caribbean origin remained associated. Further research is necessary to better understand adaptations with regard to duration and thus improve the modern criteria for ECG screening in athletes.

International Recommendations for Electrocardiographic Interpretation in Athletes

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

Sudden Cardiac Death in Athletes

There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed.

International criteria for electrocardiographic interpretation in athletes: Consensus statement

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

Acute and Chronic Response to Exercise in Athletes: The "Supernormal Heart"

During last decades, most studies have examined the exercise-induced remodeling defined as "athlete's heart". During exercise, there is an increased cardiac output that causes morphological, functional, and electrical modification of the cardiac chambers. The cardiac remodeling depends also on the type of training, age, sex, ethnicity, genetic factors, and body size. The two main categories of exercise, endurance and strength, determine different effects on the cardiac remodeling. Even if most sport comprise both strength and endurance exercise, determining different scenarios of cardiac adaptation to the exercise. The aim of this paper is to assemble the current knowledge about physiologic and pathophysiologic response of both the left and the right heart in highly trained athletes.