Electrical and structural remodelling in female athlete's heart: A comparative study in women vs men athletes and controls

BACKGROUND

Athlete's heart is associated with physiological electrical and structural remodelling. Despite the plethora of data published on male athletes, solid data derived from female athletes, compared to male counterparts or sedentary women, are still scarce.

OBJECTIVES

We aimed to analyze the electrical, structural, and functional characteristics of athlete's heart in female and male athletes vs sedentary controls.

METHODS

Olympic athletes and sedentary controls were evaluated by resting ECG and echocardiography. Athletes were divided into 4 different sports groups.

RESULTS

The study population included 1096 individuals (360 female athletes, 410 male athletes, 130 sedentary women and 196 sedentary men). Female athletes had lower resting heart rate, longer PR interval, higher voltage of R, and T waves and more frequently incomplete RBBB, left ventricular (LV) hypertrophy, early repolarization, and anterior T-wave inversion as compared to controls. Biventricular cavity dimensions and LV wall thickness were greater in female athletes than in female controls. However, women showed a lower degree of training-induced structural remodelling than men. In female athletes, both cavity dimensions and LV wall thickness increased from those engaged in skill and power to mixed and endurance disciplines. However, in female athletes, contrary to males, the ECG changes were not significantly different according to the different types of sport discipline.

CONCLUSIONS

Highly-trained women demonstrate relevant training-induced electrical and structural remodelling. However, the type of sport did not influence ECG parameters in women, contrary to men, while it impacted biventricular morphologic remodelling, with endurance athletes showing the greatest degree of adaptation.

A Patient With Athlete's Heart Syndrome: When the Abnormal Is Normal

Long-term athletic training can result in structural and conduction changes within the heart, leading to Athlete's heart syndrome (AHS). This syndrome is characterized by increased left ventricle (LV) dimensions, thickness, and mass. Dynamic exercise significantly contributes to these alterations, with sinus bradycardia being a common conduction abnormality, often accompanied by first-degree atrioventricular (AV) block. However, higher degrees of AV conduction abnormalities, such as second- and third-degree blocks, though rare, might occur due to parasympathetic hypertonia. Prompt evaluation is necessary to rule out underlying structural or infiltrative heart diseases. We present the case of a 66-year-old lifelong long-distance runner with marked sinus bradycardia, AV dissociation, and junctional escape rhythm, alongside left ventricular hypertrophy (LVH) and T-wave repolarization abnormalities. Subsequent studies ruled out possible pathologies, and the patient was diagnosed with AHS, characterized by cardiac remodeling and bradycardia due to prolonged cardiac loading. This case underscores the importance of clinical assessment, cardiac imaging, and exclusion of pathologic causes to distinguish normal physiological adaptations from potentially concerning conditions.

Cardiovascular Effects of Chronic Hormone Therapy: Study on Olympic Female Athletes

Female physiology is regulated after puberty by the menstrual cycle, whose hormonal fluctuations create a multitude of effects on several systems, including the cardiovascular one. The use of hormone therapy (HT) is quite common in female athletes, and data on cardiovascular effects in this population are lacking. We sought to investigate the effects of HT in highly trained athletes to assess any difference associated with HT on cardiac remodeling, exercise capacity, and clinical correlates. We studied 380 female elite athletes (mean age 25.5 ± 4.8) competing in endurance and mixed sports; 67 athletes (18%) were in chronic HT therapy. All athletes underwent baseline electrocardiography, exercise electrocardiography stress test, transthoracic echocardiogram, and complete blood tests, including lipid profile and inflammation indexes. The echocardiographic study showed a characteristic left ventricular (LV) remodeling, defined by lower LV mass index (86.2 vs 92.5 g/m2, p <0.006), end-diastolic LV diameter (28.3 vs 29.4 mm/m2, p <0.004), and end-diastolic LV volume (61.82 vs 67.09 ml/m2, p <0.010) compared with controls, without changes in systolic function and diastolic relaxation/filling indexes. A lower burden of ventricular arrhythmias on exercise was observed in HT athletes (1.5% vs 8.6% in those without therapy, p = 0.040). Linear regression analysis showed that HT had an independent effect on LV end-diastolic diameter indexed (p = 0.014), LV end-diastolic volume indexed (p = 0.030), and LV mass indexed (p = 0.020). In conclusion, chronic treatment with HT in female athletes is associated with less cardiac remodeling, including a lower LV cavity, volume, and mass, with preserved systolic and diastolic function, and decreased burden of exercise-induced ventricular arrhythmias. HT, therefore, appears to be responsible for a more economic but equally efficient cardiac adaptation to intensive athletic conditioning.

Cardiac magnetic resonance assessment of athletic myocardial fibrosis; Benign bystander or malignant marker?

The benefits of exercise are irrefutable with a well-established dose-dependent relationship between exercise intensity and reduction in cardiovascular disease. Differentiating the physiological adaptation to exercise, termed the "athlete's heart" from cardiomyopathies, has been advanced by the advent of more sophisticated imaging modalities such as cardiac magnetic resonance imaging (CMR). Myocardial fibrosis on CMR is a mutual finding amongst seemingly healthy endurance athletes and individuals with cardiomyopathy. As a substrate for arrhythmias, fibrosis is traditionally associated with increased cardiovascular risk. In this article, we discuss the aetiologies, distribution and potential implications of myocardial fibrosis in athletes.

Influence of isometric versus isotonic exercise training on right ventricular morpho-functional parameters in Olympic athletes

BACKGROUND

Cardiovascular adaptations in elite athletes involve both ventricular and atrial changes. Nowadays, limited research exists on right ventricular (RV) remodeling, particularly in female athletes and across different types of exercise training.

METHODS

Our study evaluated 370 athletes (61% males) participated at 2020 Tokyo and 2022 Beijing Olympic Games. Athletes were categorized according to main type of exercise into isometric and isotonic. Comprehensive echocardiographic assessments were conducted to analyze RV morpho-functional parameters, comparing genders and different sporting exercise.

RESULTS

Significant differences in RV parameters were observed based on exercise type and gender. Isotonic athletes showed greater RV remodeling with larger RV outflow tract (15.1 ± 2.1 vs. 14.5 ± 1.7 mm, p < .0001) end-diastolic and end-systolic area (respectively, 24.6 ± 5.5 vs. 21.7 ± 5 mm, p < .000 and 11.7 ± 3.2 vs. 10.1 ± 2.8 mm, p < .0001) and right atrium size (11.7 ± 3.2 vs. 10.2 ± 2.3 mm2 , p = .0001). Functional parameters, such as TDI velocities, were similar between groups. Males showed larger RV area and right atrium size (p < .0001) and lower RV TDI velocities with reduced E' (15.4 ± 2.9 vs. 16.1 ± 3.2 m/s in females, p = .031), resulting in lower E'/A' ratio (1.69 ± .6 vs. 1.84 ± .6 m/s, p = .021), while S' was lower females (14.6 ± 2.3 vs. 14.1 ± 2.4 m/s, p = .041). RV TDI velocities were similar in isotonic and isometric both in male and females.

CONCLUSIONS

In elite athletes, RV morphological changes are influenced by exercise modality but do not translate into functional differences. Female athletes present distinct RV functional profiles, with lower S' velocities and a higher E'/A' ratio. Functional RV TDI parameters are not affected by the typology of exercise practiced.

Cardiovascular and metabolic effects of hyperbilirubinemia in a cohort of Italian Olympic athletes

INTRODUCTION

Bilirubin was supposed to have cardio-metabolic protective role by signaling functions. Indeed, mild hyperbilirubinemia has immunosuppressive and endocrine activities and may offer protection against oxidative stress-mediated diseases. Gilbert syndrome (GS) has been hypothesized to provide cardio-metabolic benefits.

OBJECTIVE

To investigate the prevalence of hyperbilirubinemia and its cardio-metabolic effects in a cohort of elite Italian athletes engaged in different sports disciplines.

METHODS

We enrolled 1492 elite athletes (age 25.8 ± 5.1) practising different disciplines (power, skills, endurance, and mixed) underwent blood, echocardiographic, and exercise tests. GS was diagnosed per exclusionem in athletes with isolated asymptomatic unconjugated hyperbilirubinemia.

RESULTS

GS was highlighted in 91 athletes (6%; globally 9% male and 2.4% female); 82% were males (p < 0.0001) showing higher indirect bilirubin (0.53 ± 0.4 vs. 0.36 ± 0.24 mg/dL in females, p < 0.0001). GS athletes had fewer platelets (201 ± 35 vs. 214 ± 41, p = 0.01), higher iron (male: 124 ± 44 vs. 100.9 ± 34 mcg/dL, p < 0.0001; female: 143.3 ± 35 vs. 99.9 ± 42 mcg/dL, p < 0.0001), and lower erythrocyte sedimentation rate, (1.93 ± 0.9 vs. 2.80 ± 2.7 mm/H, p = 0.03). At multivariate analysis, male (OR 3.89, p = 0.001) and iron (OR 3.47, p = 0.001) were independently associated with GS. No significant differences were found in cardiac remodeling, heart rate, blood pressure, arrhythmias, or power capacity at stress test. Endurance athletes (313) presented higher total (p = 0.003) and indirect bilirubin (p = 0.001).

CONCLUSION

Bilirubin has several metabolic effects (including immunosuppressive and endocrine) and plays a role in regulating antioxidant pathways exercise-related with hematological consequences but seems not to affect significantly cardiovascular remodeling. Endurance athletes present higher bilirubin concentrations, likely as an adaptive mechanism to counteract increased oxidative stress.

Aortic root/left ventricular diameters golden ratio in competitive athletes

BACKGROUND

The athlete's heart is a well-known phenomenon characterized by a harmonic remodelling that affects the cardiac chambers. However, whether mild-to-moderate aortic dilatation can be considered normal in athletes is debated. This study aimed to evaluate the ratio between left ventricular (LV) size and aortic dimensions, reporting the normal values of the ratio between the aortic root diameters at the level of the sinuses of Valsalva and LV diameters (AoD/LVEDD ratio) in a wide cohort of competitive athletes.

MATERIALS AND METHODS

Competitive athletes were compared with sedentary subjects and patients with aortic dilatation. 1901 subjects who underwent echocardiography from 2019 to 2022 were retrospectively enrolled: 993 athletes (74% males, mean age 26 ± 7 years), 410 sedentary (74.1% males, mean age 29 ± 11 years) and 498 patients with aortic dilatation (74.3% males, mean age 56 ± 7 years).

RESULTS

Patients with aortic dilatation had both an absolute (39.2 ± 2.4 mm) and indexed (19.4 ± 2.2 mm/m2) aortic diameter larger than athletes (30.6 ± 3.2 mm; 16.1 ± 1.5 mm/m2, p < 0.05) and sedentary subjects (30.5 ± 3.1 mm; 16.5 ± 1.6 mm/m2, p < 0.05), with no differences between athletes and sedentary subjects. The AoD/LVEDD ratio was lower in athletes (0.59 ± 0.06) compared to controls (0.65 ± 0.05, p < 0.05) and patients with aortic dilatation (0.81 ± 0.06, p < 0.05). The patients with aortopathy had the lowest LVEDD/AoD ratio, while competitive athletes had the highest, with values of 1.71 ± 0.16 in the latter (overall p value<0.001).

CONCLUSIONS

In this study, we reported the AoD/LVEDD and LVEDD/AoD ratio values in a cohort of healthy athletes, additional parameters that could help confirm the harmonic remodelling in the athlete's heart.

Sudden Cardiac Death in Athletes: Consensuses and Controversies

Exercise is widely considered beneficial for cardiovascular health. However, on rare occasions, athletes experience sudden cardiac death without any preceding symptoms. The devastating nature of these events necessitates us to understand the underlying causes. In younger athletes (age <35), the underlying causes are usually hereditary/genetic, whereas in older athletes (age >35), coronary artery disease is prevalent. Sudden cardiac death in athletes can occur regardless of the presence of any structural abnormality in the heart. Despite divergence between guidelines, the majority of cardiology societies recommend at least taking a comprehensive history and performing physical examinations for initial screening for all athletes. This article reviews the consensuses and controversies regarding the incidence, causes, and prevention of sudden cardiac death in athletes.

Time domain adaptation of left ventricular diastolic intraventricular pressure in elite female ice hockey athletes

Background

Ice hockey is a high-intensity dynamic sport for which competitive athletes train for longer than 20 hours each week for several years. The cumulative time of myocardial exposure to hemodynamic stress affects cardiac remodeling. However, the intracardiac pressure distribution of the elite ice hockey athletes' heart during adaptation to long-term training remains to be explored. This study aimed to compare the diastolic intraventricular pressure difference (IVPD) of the left ventricle (LV) between healthy volunteers and ice hockey athletes with different training times.

Methods

Fifty-three female ice hockey athletes (27 elite and 26 casual) and 24 healthy controls were included. The diastolic IVPD of the LV during diastole was measured by vector flow mapping. The peak amplitude of the IVPD during isovolumic relaxation (P0), diastolic rapid filling (P1), and atrial systole (P4); the difference in the peak amplitude between adjacent phases (DiffP01, DiffP14); the time interval between the peak amplitude of adjacent phases (P0P1, P1P4); and the maximum decrease rate in diastolic IVPD were calculated. Differences between groups, as well as correlations between hemodynamic parameters and training time, were analyzed.

Results

Structural parameters of the LV were significantly higher in elite athletes than in casual players and controls. No significant difference in the peak amplitude of the IVPD during the diastolic phase was found among the three groups. The analysis of covariance with heart rate as a covariate showed that P1P4 in the elite athlete and casual player groups was significantly longer than that in the healthy control group (p < 0.001 for all). An increased P1P4 was significantly associated with an increased training year (β = 4.90, p < 0.001).

Conclusions

The diastolic cardiac hemodynamics of the LV in elite female ice hockey athletes could be characterized by a prolonged diastolic IVPD, and P1P4 prolonged with an increase in the training years, reflecting a time-domain adaptation in diastolic hemodynamics after long-term training.

Early repolarization in adolescent athletes: A gender comparison of ECG and echocardiographic characteristics

BACKGROUND

The early repolarization pattern (ERp) is an electrocardiographic finding previously associated with arrhythmic risk in adults. The purpose of this study is to evaluate the prevalence and characteristics of ERp in a group of adolescent athletes according to gender. Furthermore, potential associations with clinical, electrocardiographic, and echocardiographic parameters are explored.

METHODS

In this cross-sectional study young athletes (age < 18 years) were consecutively enrolled during the annual pre-participation evaluation, undergoing also transthoracic echocardiography assessment from January 2015 to March 2020.

RESULTS

The prevalence of ERp was 27% in the whole population. Athletes with ERp were more frequently men practicing endurance sports. Women with ERp showed lower heart rate at rest, greater posterior, and relative ventricular wall thickness than those without ERp. Men with ERp presented higher systolic blood pressure at peak exercise, greater septal wall thickness, and indexed left ventricular mass than those without ERp. Both genders with ERp showed increased QRS voltage and narrower QRS duration. The ERp phenotype in men was more frequently notched with higher amplitude and ascending ST segment. Women's ERp presented more frequently a slurred morphology, especially in the inferior leads, and horizontal ST slope. No differences emerged in the occurrence of arrhythmias at rest and during maximal exercise test between groups, even considering higher risk phenotypes.

CONCLUSIONS

ERp is an ECG finding compatible with normal cardiac adaptations to training in young athletes. ERp demonstrated gender differences regarding phenotypes previously associated with increased cardiovascular risk, not showing any differences in arrhythmias during maximal exercise test.

Role of the electrocardiogram in differentiating genetically determined dilated cardiomyopathy from athlete's heart

BACKGROUND

Physiological cardiac remodelling in highly trained athletes may overlap with dilated cardiomyopathy (DCM).

OBJECTIVES

The aim of this study was to investigate the role of the electrocardiogram (ECG) in differentiating between physiological and pathological remodelling.

METHODS

The study population consisted of 30 patients with DCM who revealed a pathogenic variant at genetic testing and 30 elite athletes with significant cardiac remodelling defined by a left ventricular (LV) end-diastolic diameter >62 mm and/or LV ejection fraction between 45% and 50%.

RESULTS

The ECG was abnormal in 22 (73%) patients with DCM. The most common abnormalities were low voltages (n = 14, 47%), lateral T-wave inversion (TWI) (n = 6, 20%), ventricular ectopic beats (n = 5, 17%) and anterior TWI (n = 4, 13). Two athletes revealed an abnormal ECG: complete left bundle branch block (LBBB) in one case and atrial flutter in the other. The sensitivity, specificity and accuracy of the ECG in differentiating DCM from physiological adaptation to exercise in athletes was 73% (confidence interval [CI]: 54%-88%), 93% (CI: 78%-99%) and 0.83 (CI: 0.71-0.92) respectively.

CONCLUSIONS

While the ECG is usually normal in athletes exhibiting significant LV dilatation and/or systolic dysfunction, this test is often abnormal in patients with DCM harbouring a pathogenic variant. Low voltages in the limb leads and lateral TWI are the most common abnormalities.

Cardiovascular magnetic resonance assessment of left atrial size and function in endurance athletes

Background: Left atrial (LA) dilatation is linked to cardiovascular disease and atrial fibrillation but its associations in athletes are unknown. The authors investigated whether aerobic fitness and clinical parameters are associated with LA dilatation and emptying fraction (EF) in endurance athletes. Materials & methods: 65 endurance athletes underwent cardiovascular magnetic resonance to assess LA size and function along with fitness assessment. 25 sedentary controls underwent an identical cardiovascular magnetic resonance protocol. Results: In athletes, LA volume index was elevated, while total and passive LAEFs were decreased versus sedentary controls. Increasing age and maximal oxygen uptake were associated with LA volume index. Only older age was associated with decreased total LAEF. Conclusion: LA dilatation in athletes is associated with increasing age and aerobic fitness rather than conventional cardiovascular risk factors.

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.

Sex Matters: A Comprehensive Comparison of Female and Male Hearts

Cardiovascular disease in women remains under-diagnosed and under-treated. Recent studies suggest that this is caused, at least in part, by the lack of sex-specific diagnostic criteria. While it is widely recognized that the female heart is smaller than the male heart, it has long been ignored that it also has a different microstructural architecture. This has severe implications on a multitude of cardiac parameters. Here, we systematically review and compare geometric, functional, and structural parameters of female and male hearts, both in the healthy population and in athletes. Our study finds that, compared to the male heart, the female heart has a larger ejection fraction and beats at a faster rate but generates a smaller cardiac output. It has a lower blood pressure but produces universally larger contractile strains. Critically, allometric scaling, e.g., by lean body mass, reduces but does not completely eliminate the sex differences between female and male hearts. Our results suggest that the sex differences in cardiac form and function are too complex to be ignored: the female heart is not just a small version of the male heart. When using similar diagnostic criteria for female and male hearts, cardiac disease in women is frequently overlooked by routine exams, and it is diagnosed later and with more severe symptoms than in men. Clearly, there is an urgent need to better understand the female heart and design sex-specific diagnostic criteria that will allow us to diagnose cardiac disease in women equally as early, robustly, and reliably as in men.

Systematic Review Registration

https://livingmatter.stanford.edu/.

Athlete's Heart Assessed by Sit-Up Strength Exercises in Military Men and Women: The CHIEF Heart Study

Background

Greater changes in cardiac structure and function in response to physical training have been observed more often in male athletes than in female athletes compared with their sedentary controls. However, studies for the sex-specific cardiac remodeling related to strength exercises in Asian athletes are rare.

Methods

This study included 580 men and 79 women, with an average age of 25 years, for a 6-month military training program in Taiwan. Both men and women attended a 2-min sit-up test to assess muscular strength after the training. The test performance falling one standard deviation above the mean (16%) was to define the superior eliteness of athletes. Cardiac structure and function were investigated by electrocardiography and echocardiography for men and women. Multiple logistic regression was used to determine the predictors of elite athlete status.

Results

In men, greater QTc interval, left ventricular mass adjusted to body surface area (LVMI), lateral mitral E'/A' ratio and right ventricular systolic pressure, and lower diastolic blood pressure were independent predictors of elite strength athletes in the sit-up test [odds ratio (OR) and 95% confidence intervals: 1.01 (1.00, 1.02), 1.02 (1.00, 1.04), 1.45 (1.06, 1.98), 1.13 (1.06, 1.23), and 0.96 (0.93, 0.99), respectively. In contrast, in women, the greater right ventricular outflow tract dimension was the only independent predictor of elite strength athletes in the sit-up test [OR: 1.26 (1.04, 1.53)].

Conclusions

In the 2-min sit-up test, cardiac characteristics differ between elite male and female athletes. While greater QTc interval, LVMI, and diastolic function of left ventricle predict the eliteness of male strength athletes, greater right ventricular chamber size characterizes elite female strength athletes.

Frequent Constriction-Like Echocardiographic Findings in Elite Athletes Following Mild COVID-19: A Propensity Score-Matched Analysis

Background: The cardiovascular effects of SARS-CoV-2 in elite athletes are still a matter of debate. Accordingly, we sought to perform a comprehensive echocardiographic characterization of post-COVID athletes by comparing them to a non-COVID athlete cohort. Methods: 107 elite athletes with COVID-19 were prospectively enrolled (P-CA; 23 ± 6 years, 23% female) 107 healthy athletes were selected as a control group using propensity score matching (N-CA). All athletes underwent 2D and 3D echocardiography. Left (LV) and right ventricular (RV) end-diastolic volumes (EDVi) and ejection fractions (EF) were quantified. To characterize LV longitudinal deformation, 2D global longitudinal strain (GLS) and the ratio of free wall vs. septal longitudinal strain (FWLS/SLS) were also measured. To describe septal flattening (SF-frequently seen in P-CA), LV eccentricity index (EI) was calculated. Results: P-CA and N-CA athletes had comparable LV and RVEDVi (P-CA vs. N-CA; 77 ± 12 vs. 78 ± 13mL/m2; 79 ± 16 vs. 80 ± 14mL/m2). P-CA had significantly higher LVEF (58 ± 4 vs. 56 ± 4%, p < 0.001), while LVGLS values did not differ between P-CA and N-CA (-19.0 ± 1.9 vs. -18.8 ± 2.2%). EI was significantly higher in P-CA (1.13 ± 0.16 vs. 1.01 ± 0.05, p < 0.001), which was attributable to a distinct subgroup of P-CA with a prominent SF (n = 35, 33%), further provoked by inspiration. In this subgroup, the EI was markedly higher compared to the rest of the P-CA (1.29 ± 0.15 vs. 1.04 ± 0.08, p < 0.001), LVEDVi was also significantly higher (80 ± 14 vs. 75 ± 11 mL/m2, p < 0.001), while RVEDVi did not differ (82 ± 16 vs. 78 ± 15mL/m2). Moreover, the FWLS/SLS ratio was significantly lower in the SF subgroup (91.7 ± 8.6 vs. 97.3 ± 8.2, p < 0.01). P-CA with SF experienced symptoms less frequently (1.4 ± 1.3 vs. 2.1 ± 1.5 symptom during the infection, p = 0.01). Conclusions: Elite athletes following COVID-19 showed distinct morphological and functional cardiac changes compared to a propensity score-matched control athlete group. These results are mainly driven by a subgroup, which presented with some echocardiographic features characteristic of constrictive pericarditis.

Electrocardiographic and Echocardiographic Insights From a Prospective Registry of Asian Elite Athletes

Background: Asian representation in sport is increasing, yet there remains a lack of reference values for the Asian athlete's heart. Consequently, current guidelines for cardiovascular screening recommend using Caucasian athletes' norms to evaluate Asian athletes. This study aims to outline electrocardiographic and echocardiographic characteristics of the Asian athlete's heart using a Singaporean prospective registry of Southeast (SE) Asian athletes.

Methods and Results: One hundred and fifty elite athletes, mean age of 26.1 ± 5.7 years (50% males, 88% Chinese), were evaluated using a questionnaire, 12-lead electrocardiogram (ECG) and transthoracic echocardiogram. All ECGs were analyzed using the 2017 International Recommendations. Echocardiographic data were presented by gender and sporting discipline. The prevalence of abnormal ECGs among SE Asian athletes was 6.7%—higher than reported figures for Caucasian athletes. The abnormal ECGs comprised mainly anterior T wave inversions (ATWI) beyond lead V2, predominantly in female athletes from mixed/endurance sport (9.3% prevalence amongst females). None had echocardiographic structural abnormalities. Male athletes had reduced global longitudinal strain compared to females (−18.7 ± 1.6 vs. −20.7 ± 2.1%, p < 0.001). Overall, SE Asian athletes had smaller left ventricular cavity sizes and wall thickness compared to non-Asian athletes.

Conclusion: SE Asian athletes have higher abnormal ECG rates compared to Caucasian athletes, and also demonstrate structural differences that should be accounted for when interpreting their echocardiograms compared to athletes of other ethnicities.

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.

Cardiac structure and function in elite female athletes: A systematic review and meta-analysis

We conducted a meta-analysis to synthesize the best available evidence comparing cardiac biventricular structure and function using cardiac magnetic resonance imaging (CMR) and transthoracic echocardiography (TTE) in elite female athletes and healthy controls (HC). Chronic exposure to exercise may induce cardiac chamber enlargement as a means to augment stroke volume, a condition known as the "athlete's heart." These changes have not been clearly characterized in female athletes. Multiple databases were searched from inception to June 18, 2019. Outcomes of interest included left ventricular (LV) and right ventricular (RV) dimensional, volumetric, mass, and functional assessments in female athletes. Most values were indexed to body surface area. The final search yielded 22 studies, including 1000 female athletes from endurance, strength, and mixed athletic disciplines. CMR-derived LV end-diastolic volume (LVEDV) and RV end-diastolic volume (RVEDV) were greater in endurance athletes (EA) versus HC (17.0% and 18.5%, respectively; both p < 0.001). Similarly, TTE-derived LVEDV and RVEDV were greater in EA versus HC (16.8% and 28.0%, respectively; both p < 0.001). Both LVEF and RVEF were lower in EA versus HC, with the most pronounced difference observed in RVEF via TTE (9%) (p < 0.001). LV stroke volume was greater in EA versus HC via both CMR (18.5%) and TTE (13.2%) (both p < 0.05). Few studies reported data for the mixed athlete (MA) population and even fewer studies reported data for strength athletes (SA), therefore a limited analysis was performed on MA and no analysis was performed on SA. This evidence-synthesis review demonstrates the RV may be more susceptible to ventricular enlargement. General changes in LV and RV structure and function in female EA mirrored changes observed in male counterparts. Further studies are needed to determine if potential adverse outcomes occur secondary to these changes.

Evidence of region-specific right ventricular functional adaptation in endurance-trained men in response to an acute volume infusion

NEW FINDINGS

What is the central question of this study? Endurance athletes demonstrate altered regional right ventricular (RV) wall mechanics, characterized by lower basal deformation, in comparison to non-athletic control subjects at rest. We hypothesized that regional adaptations at the RV base reflect an enhanced functional reserve capacity in response to haemodynamic volume loading. What is the main finding and its importance? Free wall RV longitudinal strain is elevated in response to acute volume loading in both endurance athletes and control subjects. However, the RV basal segment longitudinal strain response to acute volume infusion is greater in endurance athletes. Our findings suggest that training-induced cardiac remodelling might involve region-specific adaptation in the RV functional response to volume manipulation.

ABSTRACT

Eccentric remodelling of the right ventricle (RV) in response to increased blood volume and repetitive haemodynamic load during endurance exercise is well established. Structural remodelling is accompanied by decreased deformation at the base of the RV free wall, which might reflect an enhanced functional reserve capacity in response to haemodynamic perturbation. Therefore, in this study we examined the impact of acute blood volume expansion on RV wall mechanics in 16 young endurance-trained men (aged 24 ± 3 years) and 13 non-athletic male control subjects (aged 27 ± 5 years). Conventional echocardiographic parameters and the longitudinal strain and strain rate were quantified at the basal and apical levels of the RV free wall. Measurements were obtained at rest and after 7 ml/kg i.v. Gelofusine infusion, with and without a passive leg raise. After infusion, blood volume increased by 12 ± 4 and 14 ± 5% in endurance-trained individuals versus control subjects, respectively (P = 0.264). Both endurance-trained individuals (8 ± 10%) and control subjects (7 ± 9%) experienced an increase in free wall strain from baseline, which was also similar following leg raise (7 ± 10 and 6 ± 10%, respectively; P = 0.464). However, infusion evoked a greater increase in basal longitudinal strain in endurance-trained versus control subjects (16 ± 14 vs. 6 ± 11%; P = 0.048), which persisted after leg raise (16 ± 18 vs. 3 ± 11%; P = 0.032). Apical longitudinal strain and RV free wall strain rates were not different between groups and remained unchanged after infusion across all segments. Endurance training results in a greater contribution of longitudinal myocardial deformation at the base of the RV in response to a haemodynamic volume challenge, which might reflect a greater region-specific functional reserve capacity.

In Vivo Based Fluid-Structure Interaction Biomechanics of the Left Anterior Descending Coronary Artery

A fluid-structure interaction-based biomechanical model of the entire left anterior descending coronary artery is developed from in vivo imaging via the finite element method in this paper. Included in this investigation is ventricle contraction, three-dimensional motion, all angiographically visible side branches, hyper/viscoelastic artery layers, non-Newtonian and pulsatile blood flow, and the out-of-phase nature of blood velocity and pressure. The fluid-structure interaction model is based on in vivo angiography of an elite athlete's entire left anterior descending coronary artery where the influence of including all alternating side branches and the dynamical contraction of the ventricle is investigated for the first time. Results show the omission of side branches result in a 350% increase in peak wall shear stress and a 54% decrease in von Mises stress. Peak von Mises stress is underestimated by up to 80% when excluding ventricle contraction and further alterations in oscillatory shear indices are seen, which provide an indication of flow reversal and has been linked to atherosclerosis localization. Animations of key results are also provided within a video abstract. We anticipate that this model and results can be used as a basis for our understanding of the interaction between coronary and myocardium biomechanics. It is hoped that further investigations could include the passive and active components of the myocardium to further replicate in vivo mechanics and lead to an understanding of the influence of cardiac abnormalities, such as arrythmia, on coronary biomechanical responses.

Strain echocardiography to describe left ventricular function pre- and postexercise in elite basketball athletes: A feasibility study

BACKGROUND

Elite athletes show structural cardiac changes as an adaptation to exercise. Studies examining strain in athletes have largely analyzed images at rest only. There is little data available regarding the change in strain with exercise. Our objectives were: to investigate the feasibility of strain analysis in athletes at peak exercise, to determine the normal range of left ventricular (LV) global longitudinal strain (GLS) within this population postexercise, to describe how LV GLS changes with exercise, and to determine whether any clinical characteristics correlate with the change in GLS that occurs with exercise.

METHODS

We conducted a cross-sectional study on elite athletes who participated in the 2016-2018 National Basketball Association Draft Combines. Echocardiograms were obtained at rest and after completing a treadmill stress test to maximal exertion or completion of Bruce protocol. Primary outcomes included GLS obtained at rest and peak exercise. Secondary outcome was the change in GLS between rest and exercise. Univariate relationships between various clinical characteristics and our secondary outcome were analyzed.

RESULTS

Our final cohort (n = 111) was all male and 92/111 (82.9%) were African American. Mean GLS magnitude increased in response to exercise (-17.6 ± 1.8 vs -19.2 ± 2.6, P < .0001). Lower resting heart rates (r = .22, P = .02) and lower heart rates at peak exercise (r = .21, P = .03) correlated with the increase in LV GLS from exercise.

CONCLUSIONS

Strain imaging is technically feasible to obtain among elite basketball athletes at peak exercise. Normative strain response to exercise from this study may help identify abnormal responses to exercise in athletes.

Differentiation of athlete's heart and hypertrophic cardiomyopathy by the fractal dimension of left ventricular trabeculae

BACKGROUND

Differentiation between exercise induced adaptive myocardial hypertrophy (athlete's heart) and hypertrophic cardiomyopathy (HCM) is currently based on echocardiographic and cardiac magnetic resonance (CMR) criteria, but these may be insufficient in patients with subtle phenotype expression. This study aimed to assess whether left ventricular (LV) fractal pattern could permit to differentiate athlete's heart from HCM.

METHODS

We recruited retrospectively 61 elite marathon runners, 67 patients with HCM, and 33 healthy subjects. A CMR study was performed in all subjects and the LV trabeculae fractal dimension (FD) was measured in end-diastolic frames of each short-axis cine sequence. For group comparison, the ratio of maximal myocardial wall thickness (mMWT)/indexed LV end-diastolic volume (LVED) was determined.

RESULTS

As compared with athletes, patients with HCM had significantly (p < 0.001) greater FD in the LV basal (1.30 ± 0.07 vs. 1.23 ± 0.05) and apical (1.38 ± 0.06 vs. 1.30 ± 0.07) regions and in the whole heart (1.34 ± 0.05 vs. 1.27 ± 0.05). FD increased with age, left atrial area and indexed left ventricular mass (p < 0.05 for all) and correlated negatively with LV and RV end-diastolic volumes (p < 0.05 each). The addition of whole heart FD to the ratio of maximal myocardial wall thickness/indexed LVEDV lead to an improvement in the ability to discriminate HCM with a net reclassification index (NRI) of 71%.

CONCLUSIONS

The FD regional distribution of the LV trabeculae differentiates patients with athlete's heart from patients with HCM. The addition of whole heart FD to the mMWT/indexed LVEDV ratio improves the predictive capacity of the model to differentiate both entities.

Insight Into Myocardial Microstructure of Athletes and Hypertrophic Cardiomyopathy Patients Using Diffusion Tensor Imaging

BACKGROUND

Hypertrophic cardiomyopathy (HCM) remains the commonest cause of sudden cardiac death among young athletes. Differentiating between physiologically adaptive left ventricular (LV) hypertrophy observed in athletes' hearts and pathological HCM remains challenging. By quantifying the diffusion of water molecules, diffusion tensor imaging (DTI) MRI allows voxelwise characterization of myocardial microstructure.

PURPOSE

To explore microstructural differences between healthy volunteers, athletes, and HCM patients using DTI.

STUDY TYPE

Prospective cohort.

POPULATION

Twenty healthy volunteers, 20 athletes, and 20 HCM patients.

FIELD STRENGTH/SEQUENCE

3T/DTI spin echo.

ASSESSMENT

In-house MatLab software was used to derive mean diffusivity (MD) and fractional anisotropy (FA) as markers of amplitude and anisotropy of the diffusion of water molecules, and secondary eigenvector angles (E2A)-reflecting the orientations of laminar sheetlets.

STATISTICAL TESTS

Independent samples t-tests were used to detect statistical significance between any two cohorts. Analysis of variance was utilized for detecting the statistical difference between the three cohorts. Statistical tests were two-tailed. A result was considered statistically significant at P ≤ 0.05.

RESULTS

DTI markers were significantly different between HCM, athletes, and volunteers. HCM patients had significantly higher global MD and E2A, and significantly lower FA than athletes and volunteers. (MDHCM = 1.52 ± 0.06 × 10-3 mm2 /s, MDAthletes = 1.49 ± 0.03 × 10-3 mm2 /s, MDvolunteers = 1.47 ± 0.02 × 10-3 mm2 /s, P < 0.05; E2AHCM = 58.8 ± 4°, E2Aathletes = 47 ± 5°, E2Avolunteers = 38.5 ± 7°, P < 0.05; FAHCM = 0.30 ± 0.02, FAAthletes = 0.35 ± 0.02, FAvolunteers = 0.36 ± 0.03, P < 0.05). HCM patients had significantly higher E2A in their thickest segments compared to the remote (E2Athickest = 66.8 ± 7, E2Aremote = 51.2 ± 9, P < 0.05).

DATA CONCLUSION

DTI depicts an increase in amplitude and isotropy of diffusion in the myocardium of HCM compared to athletes and volunteers as reflected by increased MD and decreased FA values. While significantly higher E2A values in HCM and athletes reflect steeper configurations of the myocardial sheetlets than in volunteers, HCM patients demonstrated an eccentric rise in E2A in their thickest segments, while athletes demonstrated a concentric rise. Further studies are required to determine the diagnostic capabilities of DTI.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY STAGE: 2.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

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.

The arrhythmogenic right ventricular cardiomyopathy in comparison to the athletic heart

Intense exercise-induced right ventricular remodeling is a potential adaptation of cardiac function and structure. The features of the remodeling may overlap with those of a very early form of arrhythmogenic right ventricular cardiomyopathy (ARVC): at this early stage, it could be difficult to discriminate ARVC, from exercise-induced cardiac adaptation that may develop in normal individuals. The purpose of this paper is to discuss which exercise-induced remodeling may be a pathological or a physiological finding. A complete evaluation may be required to identify the pathological features of ARVC that would include potential risk of sudden cardiac death during sport or, to avoid the false diagnosis of ARVC. The most recent expert assessment of arrhythmogenic cardiomyopathy focuses on endurance athletes presenting with clinical features indistinguishable from ARVC.

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.

Left ventricular remodeling in elite and sub-elite road cyclists

Marked adaptation of left ventricular (LV) structure in endurance athletes is well established. However, previous investigations of functional and mechanical adaptation have been contradictory. A lack of clarity in subjects' athletic performance level may have contributed to these disparate findings. This study aimed to describe structural, functional, and mechanical characteristics of the cyclists' LV, based on clearly defined performance levels. Male elite cyclists (EC) (n = 69), sub-elite cyclists (SEC) (n = 30), and non-athletes (NA) (n = 46) were comparatively studied using conventional and speckle tracking 2D echocardiography. Dilated eccentric hypertrophy was common in EC (34.7%), but not SEC (3.3%). Chamber concentricity was higher in EC compared to SEC (7.11 ± 1.08 vs 5.85 ± 0.98 g/(mL)^2/3 , P < .001). Ejection fraction (EF) was lower in EC compared to NA (57 ± 5% vs 59 ± 4%, P < .05), and reduced EF was observed in a greater proportion of EC (11.6%) compared to SEC (6.7%). Global circumferential strain (GCε) was greater in EC (-18.4 ± 2.4%) and SEC (-19.8 ± 2.7%) compared to NA (-17.2 ± 2.6%) (P < .05 and P < .001). Early diastolic filling was lower in EC compared with SEC (0.72 ± 0.14 vs 0.88 ± 0.12 cm/s, P < .001), as were septal E' (12 ± 2 vs 15 ± 2 cm/s, P < .001) and lateral E' (18 ± 4 vs 20 ± 4 cm/s, P < .05). The magnitude of LV structural adaptation was far greater in EC compared with SEC. Increased GCε may represent a compensatory mechanism to maintain stroke volume in the presence of increased chamber volume. Decreased E and E' velocities may be indicative of a considerable functional reserve in EC.

Utility of genetic testing in athletes

Athletes are some of the fittest members of our society, yet paradoxically carry an increased risk of sudden cardiac death (SCD). The athlete's underlying risk of SCD in sports may be increased due to a number of underlying structural, arrhythmic and inherited cardiac conditions (ICCs). There are also physiological adaptations, which occur in the cardiovascular system in athletes as a result of high‐level athletic activity and may be misinterpreted as pathology. Differentiation of “athlete's heart” from heart disease may be challenging due to the effects of exercise on the electrical and structural cardiac remodeling. Features such as prolongation of the QT interval, left ventricular hypertrophy and cavity dilatation, create significant overlap between physiology and inherited channelopathies and cardiomyopathies. Most inherited cardiac conditions have an underlying genetic basis to disease and genetic testing in an athlete can have diagnostic, prognostic and therapeutic implications, including guiding exercise recommendations. Therefore, genetic testing can be a useful diagnostic tool when used carefully and appropriately by a trained cardio‐genetics expert.

Arrhythmias and Adaptations of the Cardiac Conduction System in Former National Football League Players

Background

Habitual high‐intensity endurance exercise is associated with increased atrial fibrillation (AF) risk and impaired cardiac conduction. It is unknown whether these observations extend to prior strength‐type sports exposure. The primary aim of this study was to compare AF prevalence in former National Football League (NFL) athletes to population‐based controls. The secondary aim was to characterize other conduction system parameters.

Methods and Results

This cross‐sectional study compared former NFL athletes (n=460, age 56±12 years, black 47%) with population‐based controls of similar age and racial composition from the cardiovascular cohort Dallas Heart Study‐2 (n=925, age 54±9 years, black 53%). AF was present in 28 individuals (n=23 [5%] in the NFL group; n=5 [0.5%] in the control group). After controlling for other cardiovascular risk factors in multivariable regression analysis, former NFL participation remained associated with a 5.7 (95% CI: 2.1–15.9, P<0.001) higher odds ratio of AF. Older age, higher body mass index, and nonblack race were also independently associated with higher odds ratio of AF, while hypertension and diabetes mellitus were not. AF was previously undiagnosed in 15/23 of the former NFL players. Previously undiagnosed NFL players were rate controlled and asymptomatic, but 80% had a CHA₂DS₂‐VASc score ≥1. Former NFL players also had an 8‐fold higher prevalence of paced cardiac rhythms (2.0% versus 0.25%, P<0.01), compared with controls. Furthermore, former athletes had lower resting heart rates (62±11 versus 66±11 beats per minute, P<0.001), and a higher prevalence of first‐degree atrioventricular block (18% versus 9%, P<0.001).

Conclusions

Former NFL participation was associated with an increased AF prevalence and slowed cardiac conduction when compared with a population‐based control group. Former NFL athletes who screened positive for AF were generally rate controlled and asymptomatic, but 80% should have been considered for anticoagulation based on their stroke risk.

Characterization of the dynamic changes in left ventricular morphology and function induced by exercise training and detraining

BACKGROUND

Although exercise-induced cardiac hypertrophy has been intensively investigated, its development and regression dynamics have not been comprehensively described. In the current study, we aimed to characterize the effects of regular exercise training and detraining on left ventricular (LV) morphology and function.

METHODS

Rats were divided into exercised (n = 12) and control (n = 12) groups. Exercised rats swam 200 min/day for 12 weeks. After completion of the training protocol, rats remained sedentary for 8 weeks (detraining period). Echocardiographic follow-up was performed regularly to obtain LV long- and short-axis recordings for speckle-tracking echocardiography analysis. Global longitudinal and circumferential strain and systolic strain rate were measured. LV pressure-volume analysis was performed using additional groups of rats to obtain haemodynamic data.

RESULTS

Echocardiographic examinations showed the development of LV hypertrophy in the exercised group. These differences disappeared during the detraining period. Strain and strain rate values were all increased after the training period, whereas supernormal values rapidly reversed to the control level after training cessation. Load-independent haemodynamic indices, e.g., preload recruitable stroke work, confirmed the exercise-induced systolic improvement and complete regression after detraining.

CONCLUSIONS AND TRANSLATIONAL ASPECT

Our results provide the first comprehensive data to describe the development and regression dynamics of morphological and functional aspects of physiological hypertrophy in detail. Speckle-tracking echocardiography has been proven to be feasible to follow-up changes induced by exercise training and detraining and might provide an early possibility to differentiate between physiological and pathological conditions.

Influence of Football on Physiological Cardiac Indexes in Professional and Young Athletes

Background: After long-term intensive training, considerable morphological and functional heart changes occur in professional athletes. Such changes arise progressively and regress upon interruption of the physical activity. Morphological and functional alterations on heart are known as “Athlete's heart” condition.

Objective: This study aims to compare echocardiographic parameters in two different groups of professional athletes. Furthermore, a prospective study is performed analyzing the echocardiographic changes occurring in 12 professional players in 3 years of follow-up.

Materials and Methods: 78 football players were examined from July 2011 to May 2016 (40 enrolled in Group A and 38 in Group B). Twelve players of GROUP A were followed for 3 consecutive seasons. The general clinical examination, the cardiopulmonary evaluation, the ECG, the ergometer stress test, the spirometric examination and the standard cardiac eco color doppler test were recorded.

Results: Left ventricle dimensions, left atrium dimensions, and interventricular septum dimensions were higher in A players than in B players. Moreover, following up 12 players for 3 years, a statistically significant increase of such values was observed.

Discussion: In A players, higher dimensions of the left chambers and the interventricular septum were observed, compared to B players. No statistically significant difference was found regarding the ejection fraction. The 3 years follow-up showed a statistically significant increase of both left chambers and interventricular septum dimensions, particularly in the second and third year.

Conclusions: These findings demonstrated that A players have higher echocardiographic parameters respect to B players. The results of this study support the scientific theory that long-term intensive training influences heart function, inducing “athlete's heart” with morphological adaptations. No significant echocardiographic variation within the examined sample was observed for different roles (goalkeeper, defender, midfielder, or attacker) or skills of individual players.

Evaluation of athletes with complex congenital heart disease

As a result of improvements in congenital heart surgery, there are more adults alive today with congenital heart disease (CHD) than children. Individuals with cardiac birth defects may be able to participate in physical activities but require proper cardiovascular evaluation. The American Heart Association and American College of Cardiology released guidelines in 2015 for athletes with cardiovascular abnormalities. The guidelines express that although restriction from competitive athletics may be indicated for some, the majority of individuals with CHD can and should engage in some form of physical activity. This case study demonstrates the importance of combining all aspects of history, physical examination, ECG, and imaging modalities to evaluate cardiac anatomy and function in young athletes with complex CHD.

Common electrocardiogram variations pre- and post-marathon

Electrocardiographic changes can be present in marathon runners. These findings may be misinterpreted as malignant by healthcare providers. For example, incomplete right bundle branch block, early ventricular repolarization, and left ventricular hypertrophy by voltage criteria alone are quite common in athletes, yet considered benign.

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

AIMS

Previous studies investigated the exercise-induced adaptation of left (LA) and right atrium (RA) in adults, but little is known about respective changes in the growing heart of children. We aimed to longitudinally investigate the effects of endurance training on biatrial remodelling in preadolescent athletes.

METHODS AND RESULTS

Ninety-four children (57 endurance athletes, 37 sedentary controls; mean age 10.8±0.2 and 10.2±0.2years, respectively) were evaluated at baseline and after 5months by ECG and by two-dimensional, three-dimensional (3D) and speckle-tracking echocardiography. Athletes were trained at least 10h/week. The resting heart rate was lower in athletes (p=0.046) and decreased further after training (p<0.0001). Neither athletes nor controls had ECG evidence for LA or RA enlargement. At baseline, indexed LA volumes did not differ between groups (p=0.14) but indexed RA dimensions were larger in athletes (p=0.007). After 5months, indexed LA volumes increased in athletes but not in controls (p<0.0001, p=0.29; respectively) while indexed RA volumes increased in both groups (p<0.0001, p=0.018; respectively). At the same time, slight differences in biatrial reservoir and contractile function were found either in athletes, as demonstrated by speckle-tracking echocardiography, but 3D-derived LA and RA ejection fraction remained stable in both groups.

CONCLUSION

Endurance training influences the growing heart of preadolescent athletes with an additive increase in biatrial size, suggesting that morphological adaptations can occur also in the early phases of the sports career. Training-induced remodelling was associated with a preserved biatrial function, supporting the hypothesis of a physiological remodelling.

Limits of ventricular function: from athlete's heart to a failing heart

The interest in the study of ventricular function has grown considerably in the last decades. In this review, we analyse the extreme values of ventricular function as obtained with Doppler echocardiography. We mainly focus on the parameters that have been used throughout the history of Doppler echocardiography to assess left ventricular (LV) systolic and diastolic function. The 'athlete's heart' would be the highest expression of ventricular function whereas its lowest expression is represented by the failing heart, independently from the original aetiology leading to this condition. There are, however, morphological similarities (dilation and hypertrophy) between the athlete's and the failing heart, which emerge as physiological and pathophysiological adaptations, respectively. The introduction of new assessment techniques, specifically speckle tracking, may provide new insight into the properties that determine ventricular filling, specifically left ventricular twisting. The concept of ventricular function must be always considered, although it may not be always possible to distinguish the normal heart of sedentary individuals from that of highly trained hearts based solely on echocardiographic or basic studies.

Strain and strain rate by speckle-tracking echocardiography correlate with pressure-volume loop-derived contractility indices in a rat model of athlete's heart

Contractile function is considered to be precisely measurable only by invasive hemodynamics. We aimed to correlate strain values measured by speckle-tracking echocardiography (STE) with sensitive contractility parameters of pressure-volume (P-V) analysis in a rat model of exercise-induced left ventricular (LV) hypertrophy. LV hypertrophy was induced in rats by swim training and was compared with untrained controls. Echocardiography was performed using a 13-MHz linear transducer to obtain LV long- and short-axis recordings for STE analysis (GE EchoPAC). Global longitudinal (GLS) and circumferential strain (GCS) and longitudinal (LSr) and circumferential systolic strain rate (CSr) were measured. LV P-V analysis was performed using a pressure-conductance microcatheter, and load-independent contractility indices [slope of the end-systolic P-V relationship (ESPVR), preload recruitable stroke work (PRSW), and maximal dP/dt-end-diastolic volume relationship (dP/dtmax-EDV)] were calculated. Trained rats had increased LV mass index (trained vs. control; 2.76 ± 0.07 vs. 2.14 ± 0.05 g/kg, P < 0.001). P-V loop-derived contractility parameters were significantly improved in the trained group (ESPVR: 3.58 ± 0.22 vs. 2.51 ± 0.11 mmHg/μl; PRSW: 131 ± 4 vs. 104 ± 2 mmHg, P < 0.01). Strain and strain rate parameters were also supernormal in trained rats (GLS: -18.8 ± 0.3 vs. -15.8 ± 0.4%; LSr: -5.0 ± 0.2 vs. -4.1 ± 0.1 Hz; GCS: -18.9 ± 0.8 vs. -14.9 ± 0.6%; CSr: -4.9 ± 0.2 vs. -3.8 ± 0.2 Hz, P < 0.01). ESPVR correlated with GLS (r = -0.71) and LSr (r = -0.53) and robustly with GCS (r = -0.83) and CSr (r = -0.75, all P < 0.05). PRSW was strongly related to GLS (r = -0.64) and LSr (r = -0.71, both P < 0.01). STE can be a feasible and useful method for animal experiments. In our rat model, strain and strain rate parameters closely reflected the improvement in intrinsic contractile function induced by exercise training.

Left ventricular strain modifications after maximal exercise in athletes: a speckle tracking study

PURPOSE

The increase in systolic indexes from rest (R) to exercise is achieved by combination of enhanced heart rate (HR) and stroke volume (SV). Aim of this study was to evaluate left ventricular (LV) longitudinal, circumferential, and torsional components immediately after a maximal intensity exercise (ME) by speckle tracking echocardiography (STE).

METHODS

Twenty-seven male water polo players performed an ME that consisted of 6 repeats of 100 m freestyle swim sets. An echocardiographic examination was performed before and after ME. STE was performed to obtain the analysis of LV myocardial deformation.

RESULTS

There were no differences between R and ME regarding LV longitudinal strains (PVLS). Apical circumferential LV strain (AVCS) and LV longitudinal strain rate (SR) increased at ME with respect to R (R: -23.1 ± 4.9%; ME: -28.4 ± 7.6%, P < 0.05; R: -1.1 ± 0.1/sec, ME: -1.5 ± 0.2/sec, P < 0.01). LV twisting (LVT) and untwisting (UTW) increased at ME (R: 7.9 ± 2.4°, ME: 14.2 ± 3.2°, P < 0.001; R: -107.2 ± 47.4; ME: -158.5 ± 61.5 °/sec; P < 0.01). At ME, apical rotation (Arot) had higher values than R values (5.4 ± 3.0°; 10.0 ± 6.0°; P < 0.01) and time-to-peak (TTP) of apical segments are earlier than all TTP. SV was related to LVT (r = 0.56, P = 0.01), AVCS (r = -0.59, P = 0.005) and Arot (r = 0.46, P = 0.04). At multivariate analysis, AVCS was the independent predictor of SV (β = -0.58; P < 0.05).

CONCLUSIONS

Apical fibers and LVT give the main contribution to systolic components at ME. The storage of energy during LVT, released during early diastole, seems to be a fundamental mechanism to support diastolic filling during maximal exercise.

Ablation of frequent premature ventricular complex in an athlete

Premature ventricular complex are common findings in the exam of many athletes. There is no extensive scientific evidence in the management of this situation particularly when associated with borderline contractile function of the left ventricle. In this case report, we present a 35-year-old asymptomatic healthy athlete with high incidence (over 10,000 beats in 24 h) of premature ventricular complex and left ventricular dilatation with dysfunction, which persisted after a resting period of 6 months without training. We performed radiofrequency ablation of the premature ventricular complex focus. After 1-year follow-up, he was asymptomatic without arrhythmia and the left ventricle normalized its size and function as shown by echocardiogram and cardiac magnetic resonance.

Endogenous α-calcitonin-gene-related peptide promotes exercise-induced, physiological heart hypertrophy in mice

AIM

It is unknown how the heart distinguishes various overloads, such as exercise or hypertension, causing either physiological or pathological hypertrophy. We hypothesize that alpha-calcitonin-gene-related peptide (αCGRP), known to be released from contracting skeletal muscles, is key at this remodelling.

METHODS

The hypertrophic effect of αCGRP was measured in vitro (cultured cardiac myocytes) and in vivo (magnetic resonance imaging) in mice. Exercise performance was assessed by determination of maximum oxygen consumption and time to exhaustion. Cardiac phenotype was defined by transcriptional analysis, cardiac histology and morphometry. Finally, we measured spontaneous activity, body fat content, blood volume, haemoglobin mass and skeletal muscle capillarization and fibre composition.

RESULTS

While αCGRP exposure yielded larger cultured cardiac myocytes, exercise-induced heart hypertrophy was completely abrogated by treatment with the peptide antagonist CGRP(8-37). Exercise performance was attenuated in αCGRP(-/-) mice or CGRP(8-37) treated wild-type mice but improved in animals with higher density of cardiac CGRP receptors (CLR-tg). Spontaneous activity, body fat content, blood volume, haemoglobin mass, muscle capillarization and fibre composition were unaffected, whereas heart index and ventricular myocyte volume were reduced in αCGRP(-/-) mice and elevated in CLR-tg. Transcriptional changes seen in αCGRP(-/-) (but not CLR-tg) hearts resembled maladaptive cardiac phenotype.

CONCLUSIONS

Alpha-calcitonin-gene-related peptide released by skeletal muscles during exercise is a hitherto unrecognized effector directing the strained heart into physiological instead of pathological adaptation. Thus, αCGRP agonists might be beneficial in heart failure patients.

Adaptation of heart to training: a comparative study using echocardiography & impedance cardiography in male & female athletes

BACKGROUND & OBJECTIVES

Intensive regular physical exercise training is associated with a physiological changes in left ventricular (LV) morphology and functions. This cardiac remodeling observed in the athletes is associated with the specific haemodynamic requirements of the exercise undertaken. The main objective of this study is to evaluate the effect of endurance training on cardiac morphology, systolic and diastolic LV functions and haemodynamic parameters both in male and female athletes.

METHODS

Seventy nine healthy athletes (age 20.0 ± 2.6 yr; 49% male) and 82 healthy sedentary adolescent (age 20.8 ± 2.2 yr, 49% male) volunteered to participate in this study. All subjects underwent transthoracic echocardiography and impedance cardiography.

RESULTS

Both female and male athletes had greater LV end-diastolic cavity sizes, LV mass and stroke volume (SV) values when compared with controls. Also, in male athletes, LV mass index was higher than in female athletes. While male athletes had lower resting heart rate compared to female athletes, they had higher mean arterial blood pressure. In male athletes, basal septal and mid septal strain values were higher compared to controls. There were no significant differences in strain and peak systolic strain rate values between female athletes and controls. In male athletes, there was a weak positive correlation between SV and LV mass, basal lateral and septal strain values. In female athletes, only a weak positive correlation was found between SV and basal septal strain values.

INTERPRETATION & CONCLUSIONS

Endurance-trained male and female athletes had higher LV mass, LV cavity dimensions and SV compared to sedentary controls. Although there was no difference in diastolic cardiac functions between athletes and controls, local enhanced systolic function was found with increase of SV. Both morphologic and haemodynamic differences were more evident in male athletes.

Hypertrophic cardiomyopathy and ultra-endurance running - two incompatible entities?

Regular and prolonged exercise is associated with increased left ventricular wall thickness that can overlap with hypertrophic cardiomyopathy (HCM). Differentiating physiological from pathological hypertrophy has important implications, since HCM is the commonest cause of exercise-related sudden cardiac death in young individuals. Most deaths have been reported in intermittent 'start-stop' sports such as football (soccer) and basketball. The theory is that individuals with HCM are unable to augment stroke volume sufficiently to meet the demands of endurance sports and are accordingly 'selected-out' of participation in such events. We report the case of an ultra-endurance athlete with 25 years of > 50 km competitive running experience, with genetically confirmed HCM; thereby demonstrating that these can be two compatible entities.

A Century of Cardiomythology: Exercise and the Heart c.1880–1980

The relationship between health and exercise involves risks as well as rewards. This article focuses on heart disease and the marathon to show how doctors have negotiated that relationship over a century. Three distinct changes in biomedical attitudes towards vigorous exercise are outlined. First, the mid-Victorian interpretation of pathological hypertrophy of the heart was overturned at the end of the nineteenth century. Secondly, hypertrophy was reinvented as a beneficial physiological adaptation in the 1940s and 1950s. Thirdly, these claims of distinctiveness were challenged by the leisure revolution. Sports doctors and cardiologists reinvented exercise as a drug that could only be safely used with the guidance of a medical professional. Medicalising sport reduced its risk and maximised its reward, both to the individual and the state.

Influence of angiotensin-converting enzyme gene polymorphism on development of athlete's heart

BACKGROUND AND HYPOTHESIS

Genetic influence on development of athlete's heart is uncertain. This study investigated whether angiotensin-converting enzyme (ACE) gene polymorphism influenced development of athlete's heart.

METHODS

Forty-three participants in a 100-km ultramarathon were classified on the basis of ACE gene polymorphism into a deletion group (n = 26) and an insertion group (n = 17). Echocardiograms were recorded to determine left ventricular end-diastolic and end-systolic diameters, interventricular septal thickness, left ventricular posterior wall thickness, left ventricular mass, and ejection fraction.

RESULTS

Left ventricular end-diastolic diameter (65.5 +/- 4.0 mm) and left ventricular mass (369.5 +/- 73.9 g) were significantly larger in the subjects with deletion than in those with insertion (57.4 +/- 4.2 mm, 306.5 +/- 93.7 g). However, no significant differences in the other parameters were noted.

CONCLUSIONS

In long-distance runners, ACE gene polymorphism of the D/D and D/I genotypes has a stronger influence on left ventricular hypertrophy than polymorphism of the I/I genotype.