The athlete's heart syndrome: a new perspective

The differentiation of the competitive athlete with physiologic cardiac remodeling from the athlete with cardiomyopathy

There are currently 5 million active high school, collegiate, professional, and master athletes in the United States. Regular intense exercise by these athletes can promote structural, electrical and functional remodeling of the heart, which is termed the "athlete's heart." In addition, regular intense exercise can lead to pathological adaptions that promote or worsen cardiac disease. Many of the athletes in the United States seek medical care. Consequently, physicians must be aware of the normal cardiac anatomy and physiology of the athlete, the differentiation of the normal athlete heart from the athlete with cardiomyopathy, and the contemporary care of the athlete with a cardiomyopathy. In athletes with persistent cardiovascular symptoms, investigations should include a detailed history and physical examination, an ECG, a transthoracic echocardiogram, and in athletes in whom the diagnosis is uncertain, a maximal exercise stress test or a continuous ECG recording, and cardiac magnetic resonance imaging or cardiac computed tomography angiography when definition of the coronary anatomy or characterization of the aorta and the aortic great vessels is indicated. This article discusses the differentiation of the normal athlete with physiologic cardiac remodeling from the athlete with hypertrophic, dilated or arrhythmogenic ventricular cardiomyopathy (ACM). The ECG changes in trained athletes that are considered normal, borderline, or abnormal are listed. In addition, the normal echocardiographic measurements for athletes who consistently participate in endurance, power, combined or heterogeneous sports are enumerated and discussed. Algorithms are listed that are useful in the diagnosis of trained athletes with borderline or abnormal echocardiographic measurements suggestive of cardiomyopathies along with the major and minor criteria for the diagnosis of ACM in athletes. Thereafter, the treatment of athletes with hypertrophic, dilated, and arrhythmogenic right ventricular cardiomyopathies are reviewed. The distinction between physiologic changes and pathologic changes in the hearts of athletes has important therapeutic and prognostic implications. Failure by the physician to correctly diagnose an athlete with hypertrophic cardiomyopathy, dilated cardiomyopathy, or ACM, can lead to the sudden cardiac arrest and death of the athlete during training or sports competition. Conversely, an incorrect diagnosis by a physician of cardiac pathology in a normal athlete can lead to an unnecessary restriction of athlete training and competition with resultant significant emotional, psychological, financial, and long-term health consequences in the athlete.

Echocardiographic assessment of left ventricular volumes: a comparison of different methods in athletes

BACKGROUND

Cardiac magnetic resonance imaging (cMRI) is considered the gold standard for the assessment of left ventricular (LV) systolic function. However, discrepancies have been reported in the literature between LV volumes assessed by transthoracic echocardiography (TTE) and cMRI. The objective of this study was to analyze the differences in LV volumes between different echocardiographic techniques and cMRI.

METHODS AND RESULTS

In 64 male athletes (21.1 ± 4.9 years), LV volumes were measured by TTE using the following methods: Doppler echocardiography, anatomical M-Mode, biplane/triplane planimetry and 3D volumetry. In addition, LV end-diastolic (LVEDV), end-systolic (LVESV), and stroke volumes (LVSV) were assessed in 11 athletes by both TTE and cMRI. There was no significant difference between LVEDV and LVESV determined by biplane/triplane planimetry and 3D volumetry. LVEDV and LVESV measured by M-Mode were significantly lower compared to 3D volumetry. LVSV determined by Doppler with 3D planimetry of LV outflow tract was significantly higher than 2D planimetry and 3D volumetry, whereas none of the planimetric or volumetric methods for determining LVSV differed significantly. There were no significant differences for LVEDV, LVESV, LVSV and LVEF between cMRI and TTE determined by biplane planimetry in the subgroup of 11 athletes.

CONCLUSION

The choice of echocardiographic method used has an impact on LVSV in athletes, so the LVSV should always be checked for plausibility. The same echocardiographic method should be used to assess LVSV at follow-ups to ensure good comparability. The data suggest that biplane LV planimetry by TTE is not inferior to cMRI.

Cardiac Adaptation in Power Athletes: Differential Impact of Judo and Weightlifting

Background: According to the ESC guidelines, sport disciplines are classified in relation to the predominant component (skill, power, mixed and endurance), including a wide range of disciplines with different isometric/isotonic exercises and exercise-induced heart remodeling. The aim of our study was to evaluate differences in morpho-functional cardiac adaptations in power athletes, comparing judokas with weightlifters. Methods: We enrolled 55 Olympic athletes (38 judokas, 17 weightlifters), aged 24.5 ± 3.8 years, 25 (45.4%) of whom were males, and they underwent a pre-participation evaluation, including a physical examination, ECG, transthoracic echocardiogram, and exercise stress test. Results: The judokas presented significant differences in cardiac adaptations, with larger left ventricle (LV) end-diastolic and end-systolic volumes indexed (LVEDVi, p = 0.002 and LVESVi, p = 0.004) and higher LVMass values indexed (p = 0.033), but similar LV wall thicknesses (p = 0.093) and LV ejection fractions (p = 0.981). Also, the left atrium (LA) dimension (p = 0.0002) and volume indexed (p < 0.0001) were higher in the judokas, as were the larger right ventricle (RV) areas. Finally, the judokas showed higher VO2max (p = 0.012), O2 pulse (p = 0.007), VE/O2 LT1 (p = 0.041) and VE/O2 LT2 (p = 0.036) values, with a lower resting heart rate (p = 0.031) and higher exercise capacity (p = 0.011). Conclusions: The judokas showed substantial differences in cardiac morpho-functional adaptations from the weightlifters, and, accordingly, judo should be more properly considered not a pure strength sport but more similar to mixed disciplines of the ESC classification.

Lack of cardiac remodelling in elite endurance athletes: an unexpected and not so rare finding

PURPOSE

Endurance elite athletes are expected to present a cardiac remodelling, characterized by eccentric hypertrophy (EH), may be associated with higher sportive performances. However, not all can present a cardiac remodelling. The study aimed to identify endurance athletes without cardiac remodelling characterizing their physiologic and clinical features.

METHODS

We studied 309 endurance athletes (cycling, rowing, canoeing, triathlon, athletics, long-distance swimming, cross-country skiing, mid-long distance track, pentathlon, biathlon, long-distance skating and Nordic-combined) examined during period of training, by clinical evaluation, ECG, echocardiogram and exercise-stress test. Sport career achievements (Olympic\World championship medals or national\world records) were recorded.

RESULTS

EH was found in most of athletes, (n = 126, 67% of males; n = 85, 68.5% of females). A significant proportion,, exhibited normal geometry (NG) ( n = 59, 31.3% in males; n = 39, 31.4% in females). At stress test, significant differences between EH and NG athletes were found in peak power (317.1 ± 71.2W in NG vs. 342.2 ± 60.6W in EH, p = 0.014 in males and 225.1 ± 38.7W in NG vs. 247.1 ± 37W in EH, p = 0.003 in females), rest heart rate (66.1 ± 13 in NG vs. 58.6 ± 11.6 in EH, p = 0.001 in males and 68 ± 13.2 in NG vs. 59.2 ± 11.2 in EH, p = 0.001 in females) with similar ventricular extrasystoles (p = 0.363 in males and p = 0.492 in females). However, no significant differences in athletic achievements were registered.

CONCLUSION

Our study demonstrates a relatively high prevalence of NG in endurance athletes, in addition to the expected EH. Athletes with NG perform worse in exercise-stress test and exhibit some less advantageous functional heart characteristics. However, the type of heart geometry is not associated with negative clinical findings.

Team Approach: Diagnosis, Management, and Prevention of Sudden Cardiac Arrest in the Athlete

» Sudden cardiac events during sports competition are rare but tragic occurrences that require a timely, comprehensive response by well-prepared athletic trainers and medical providers. This sequence should prioritize prompt emergency medical system activation, immediate initiation of cardiopulmonary resuscitation (CPR), automated early defibrillation (AED), and comprehensive advanced life support efforts.» Exercise-induced cardiac remodeling, referred to as the "athlete's heart," refers to a host of adaptive changes that increase cardiac chamber size and wall thickness to allow for greater pressures and volumes during exercise. This remodeling phenotype may overlap with other inherited cardiomyopathies and cardiac abnormalities, which can complicate clinical care. The long-term implications of this electrical and structural remodeling on cardiac function are unknown.» Although the best screening strategies to optimize primary prevention of sudden cardiac arrest is an evolving topic, the effectiveness of CPR and early defibrillation use in treating out-of-hospital sudden cardiac arrest has been well-established, despite their reported underuse.

Effects of a 20-Week High-Intensity Strength Training Program on Muscle Strength Gain and Cardiac Adaptation in Untrained Men: Preliminary Results of a Prospective Longitudinal Study

BACKGROUND

As strength sports gain popularity, there is a growing need to explore the impact of sustained strength training on cardiac biventricular structure and function, an area that has received less attention compared to the well-established physiological cardiac adaptation to endurance training.

OBJECTIVE

This study aims to implement a 20-week high-intensity strength training program to enhance maximal muscle strength and evaluate its impact on cardiac biventricular adaptation in healthy, untrained men.

METHODS

A total of 27 healthy and untrained young men (mean age 22.8, SD 3.2 years) participated in a strength training program designed to increase muscle strength. The training program involved concentric, eccentric, and isometric exercise phases, conducted over a consecutive 20-week time frame with a frequency of 3 weekly training sessions. Participants were evaluated before and after 12 and 20 weeks of training through body composition analysis (bioelectrical impedance), a 12-lead resting electrocardiogram, 3D transthoracic echocardiography, cardiopulmonary exercise testing, and muscle isokinetic dynamometry. The progression of strength training loads was guided by 1-repetition maximum (RM) testing during the training program.

RESULTS

Of the initial cohort, 22 participants completed the study protocol. No injuries were reported. The BMI (mean 69.8, SD 10.8 kg/m² vs mean 72, SD 11 kg/m²; P=.72) and the fat mass (mean 15.3%, SD 7.5% vs mean 16.5%, SD 7%; P=.87) remained unchanged after training. The strength training program led to significant gains in 1-RM exercise testing as early as 4 weeks into training for leg extension (mean 69.6, SD 17.7 kg vs mean 96.5, SD 31 kg; P<.001), leg curl (mean 43.2, SD 9.7 kg vs mean 52.8, SD 13.4 kg; P<.001), inclined press (mean 174.1, SD 41.1 kg vs mean 229.2, SD 50.4 kg; P<.001), butterfly (mean 26.3, SD 6.2 kg vs mean 32.5, SD 6.6 kg; P<.001), and curl biceps on desk (mean 22.9, SD 5.2 kg vs mean 29.6, SD 5.2 kg; P<.001). After 20 weeks, the 1-RM leg curl, bench press, pullover, butterfly, leg extension, curl biceps on desk, and inclined press showed significant mean percentage gains of +40%, +41.1%, +50.3%, +63.5%, +80.1%, +105%, and +106%, respectively (P<.001). Additionally, the isokinetic evaluation confirmed increases in maximal strength for the biceps (+9.2 Nm), triceps (+11.6 Nm), quadriceps (+46.8 Nm), and hamstrings (+25.3 Nm). In this paper, only the training and muscular aspects are presented; the cardiac analysis will be addressed separately.

CONCLUSIONS

This study demonstrated that a short-term high-intensity strength training program was successful in achieving significant gains in muscle strength among previously untrained young men. We intend to use this protocol to gain a better understanding of the impact of high-intensity strength training on cardiac physiological remodeling, thereby providing new insights into the cardiac global response in strength athletes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04187170; https://clinicaltrials.gov/study/NCT04187170.

Mitral and Tricuspid Valve Disease in Athletes

Observing mitral or tricuspid valve disease in an athlete raises many considerations for the clinician. Initially, the etiology must be clarified, with causes differing depending on whether the athlete is young or a master. Notably, vigorous training in competitive athletes leads to a constellation of structural and functional adaptations involving cardiac chambers and atrioventricular valve systems. In addition, a proper evaluation of the athlete with valve disease is necessary to evaluate the eligibility for competitive sports and identify those requiring more follow-up. Indeed, some valve pathologies are associated with an increased risk of severe arrhythmias and potentially sudden cardiac death. Traditional and advanced imaging modalities help clarify clinical doubts, allowing essential information about the athlete's physiology and differentiating between primary valve diseases from those secondary to training-related cardiac adaptations. Remarkably, another application of multimodality imaging is evaluating athletes with valve diseases during exercise to reproduce the sport setting and better characterize the etiology and valve defect mechanism. This review aims to analyze the possible causes of atrioventricular valve diseases in athletes, focusing primarily on imaging applications in diagnosis and risk stratification.

Normative Values for Sport-Specific Left Ventricular Dimensions and Exercise-Induced Cardiac Remodeling in Elite Spanish Male and Female Athletes

Background

There is debate about the magnitude of geometrical remodeling [i.e., left ventricle (LV) cavity enlargement vs. wall thickening] in the heart of elite athletes, and no limits of normality have been yet established for different sports. We aimed to determine sex- and sport-specific normative values of LV dimensions in elite white adult athletes.

Methods

This was a single-center, retrospective study of Spanish elite athletes. Athletes were grouped by sport and its relative dynamic/static component (Mitchell’s classification). LV dimensions were measured with two-dimensional-guided M-mode echocardiography imaging to compute normative values. We also developed an online and app-based calculator (https://sites.google.com/lapolart.es/athlete-lv/welcome?authuser=0) to provide clinicians with sports- and Mitchell’s category-specific Z-scores for different LV dimensions.

Results

We studied 3282 athletes (46 different sports, 37.8% women, mean age 23 ± 6 years). The majority (85.4%) showed normal cardiac geometry, particularly women (90.9%). Eccentric hypertrophy was relatively prevalent (13.4%), and concentric remodeling or hypertrophy was a rare finding (each < 0.8% of total). The proportion of normal cardiac geometry and eccentric hypertrophy decreased and increased, respectively, with the dynamic (in both sexes) or static component (in male athletes) of the sport irrespective of the other (static or dynamic) component. The 95th percentile values of LV dimensions did not exceed the following limits in any of the Mitchell categories: septal wall thickness, 12 mm (males) and 10 mm (females); LV posterior wall, 11 mm and 10 mm; and LV end-diastolic diameter, 64 mm and 57 mm.

Conclusions

The majority of elite athletes had normal LV geometry, and although some presented with LV eccentric hypertrophy, concentric remodeling or hypertrophy was very uncommon. The present study provides sport-specific normative values that can serve to identify those athletes for whom a detailed examination might be recommendable (i.e., those exceeding the 95th percentile for their sex and sport).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00510-2.

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.

From talented child to elite athlete: The development of cardiac morphology and function in a cohort of endurance athletes from age 12 to 18

BACKGROUND

Adult athletes undergo cardiac adaptions in what is known as the "athlete's heart". Cardiac adaptations in young athletes have not been described in longitudinal studies but have previously been believed to be uniform in nature.

METHODS

Seventy-six cross-country skiers were assessed at age 12. Forty-eight (63%) completed the first follow-up at age 15 and 36 (47%) the second follow-up at age 18. Comprehensive exercise data were collected. Echocardiography with three-dimensional measurements and cardiopulmonary exercise testing were performed at all time points. The cohort was divided into active and former endurance athletes, with an eight hours of weekly endurance exercise cut-off at age 18.

RESULTS

The athletes underwent eccentric remodelling between ages 12 and 15, and concentric remodelling between ages 15 and 18. At age 18, the active endurance athletes had greater increases in inter-ventricular wall thickness (1.8 ± 1.4 Δmm vs 0.6 ± 1.0 Δmm, p < 0.05), left ventricular (LV) posterior wall thickness (1.6 ± 1.2 Δmm vs 0.8 ± 0.8 Δmm, p < 0.05), LV mass (63 ± 30 Δg vs 27 ± 21 Δg, p < 0.01), right ventricular (RV) end-diastolic area (3.4 ± 4.0 Δcm2 vs 0.6 ± 3.5Δ cm2, p < 0.05), RV end-systolic area (1.0 ± 2.3 Δcm2 vs -0.9 ± 2.0 Δcm2, p < 0.05) and left atrial volume (24 ± 21 ΔmL vs 6±10 ΔmL, p < 0.05) and had greater indexed maximal oxygen uptake (66.3 ± 7.4 mL/min/kg vs 57.1 ± 8.2 mL/min/kg, p < 0.01). There was no significant difference for LV volumes.

CONCLUSION

This study finds a shift in the development of the young athlete's heart. Between ages 12 and 15, the active endurance athletes underwent eccentric remodelling. This dynamic switched to concentric remodelling between ages 15 and 18.

The developing athlete's heart: a cohort study in young athletes transitioning through adolescence

Background

Athlete's heart is a term used to describe physiological changes in the hearts of athletes, but its early development has not been described in longitudinal studies. This study aims to improve our understanding of the effects of endurance training on the developing heart.

Methods

Cardiac morphology and function in 48 cross-country skiers were assessed at age 12 years (12.1 ± 0.2 years) and then again at age 15 years (15.3 ± 0.3 years). Echocardiography was performed in all subjects including two-dimensional speckle-tracking strain echocardiography and three-dimensional echocardiography. All participants underwent cardiopulmonary exercise testing at both ages 12 and 15 years to assess maximal oxygen uptake and exercise capacity.

Results

Thirty-one (65%) were still active endurance athletes at age 15 years and 17 (35%) were not. The active endurance athletes had greater indexed maximal oxygen uptake (62 ± 8 vs. 57 ± 6 mL/kg/min, P < 0.05) at follow-up. There were no differences in cardiac morphology at baseline. At follow-up the active endurance athletes had greater three-dimensional indexed left ventricular end-diastolic (84 ± 11 mL/m2 vs. 79 ± 10 mL/m2, P < 0.05) and end-systolic volumes (36 ± 6 mL/m2 vs. 32 ± 3 mL/m2, P < 0.05). Relative wall thickness fell in the active endurance athletes, but not in those who had quit (–0.05 ΔmL/m2 vs. 0.00 mL/m2, P = 0.01). Four active endurance athletes had relative wall thickness above the upper reference values at baseline; all had normalised at follow-up.

Conclusion

After an initial concentric remodelling in the pre-adolescent athletes, those who continued their endurance training developed eccentric changes with chamber dilatation and little change in wall thickness. Those who ceased endurance training maintained a comparable wall thickness, but did not develop chamber dilatation.

Ultrasound in sports medicine: relevance of emerging techniques to clinical care of athletes

The applications of ultrasound in managing the clinical care of athletes have been expanding over the past decade. This review provides an analysis of the research that has been published regarding the use of ultrasound in athletes and focuses on how these emerging techniques can impact the clinical management of athletes by sports medicine physicians. Electronic database literature searches were performed using the subject terms 'ultrasound' and 'athletes' from the years 2003 to 2012. The following databases were searched: PubMed, Web of Science, Cochrane Library, CINAHL, and SPORTDiscus™. The search produced 617 articles in total, with a predominance of articles focused on cardiac and musculoskeletal ultrasound. 266 of the studies involved application of ultrasound in evaluating the cardiovascular properties of athletes, and 151 studies involved musculoskeletal ultrasound. Other applications of ultrasound included abdominal, vascular, bone density and volume status. New techniques in echocardiography have made significant contributions to the understanding of the physiological changes that occur in the athlete's heart in response to the haemodynamic stress associated with different types of activity. The likely application of these techniques will be in managing athletes with hypertrophic cardiomyopathy, and the techniques are near ready for application into clinical practice. These techniques are highly specialized, however, and will require referral to dedicated laboratories to influence the clinical management of athletes. Investigation of aortic root pathology and pulmonary vascular haemodynamics are also emerging, but will require additional studies with larger numbers and outcomes analysis to validate their clinical utility. Some of these techniques are relatively simple, and thus hold the potential to enter clinical management in a point-of-care fashion. Musculoskeletal ultrasound has demonstrated a number of diagnostic and therapeutic techniques applicable to pathology of the shoulder, elbow, wrist, hand, hip, knee and ankle. These techniques have been applied mainly to the management of impingement syndromes, tendinopathies and arthritis. Many of these techniques have been validated and have entered clinical practice, while more recently developed techniques (such as dynamic ultrasound and platelet-rich plasma injections) will require further research to verify efficacy. Research in musculoskeletal ultrasound has also been helpful in identifying risk factors for injury and, thus, serving as a focus for developing interventions. Research in abdominal ultrasound has investigated the potential role of ultrasound imaging in assessing splenomegaly in athletes with mononucleosis, in an attempt to inform decisions and policies regarding return to play. Future research will have to demonstrate a reduction in adverse events in order to justify the application of such a technique into policy. The role of ultrasound in assessing groin pain and abdominal pain in ultraendurance athletes has also been investigated, providing promising areas of focus for the development of treatment interventions and physical therapy. Finally, preliminary research has also identified the role of ultrasound in addressing vascular disease, bone density and volume status in athletes. The potential applications of ultrasound in athletes are broad, and continuing research, including larger outcome studies, will be required to establish the clinical utility of these techniques in the care of athletes.

Cardiac dimensions over 5 years in highly trained long-distance runners and sprinters

AIMS

We assessed the changes in cardiac morphology between elite endurance-trained runners (n = 42) and elite sprinters (n = 34) over a 5-year period. In addition, we studied the relationship between heart size and maximum oxygen consumption (VO2 max).

METHODS

At the beginning of 5 consecutive seasons, all athletes underwent an incremental running test to determine VO2 max and a color-coded pulsed Doppler examination to determine baseline echocardiographic variables. We hypothesized that cardiac morphology had reached its upper limit in elite athletes, and showed only minor changes during 5 years of regular training.

RESULTS

Although all echocardiographic variables remained stable in nearly all sprinters studied, in the endurance runners (who presented higher cardiac cavity dimensions compared with sprinters), variations in heart morphology became evident from the third season, and were within established physiological limits.

CONCLUSION

Only 6 (17%) endurance runners and 3 (9%) sprinters showed a left ventricular internal diameter of > 60 mm (the threshold pathological value) at end diastole at some point during the observational period. Moreover, no statistically significant association was detected between changes in VO2 max and changes in heart size. After 5 years of intense training, the changes of the echocardiographic variables examined remained different between endurance runners and sprinters.

MMP-2 mediates angiotensin II-induced hypertension under the transcriptional control of MMP-7 and TACE

Development of cardiovascular disease induced by excessive Gq protein-coupled receptor agonist stimulation depends on signaling networks involving multiple matrix metalloproteinases (MMPs) and metalloproteinase disintegrins (ADAMs). Here, we hypothesized that MMP-2, being a major gelatinase in cardiac and vascular tissue, was likely to play a key role in cardiovascular homeostasis. We targeted MMP-2 using complementary and overlapping approaches involving pharmacological inhibition and RNA interference in mice treated with angiotensin II (1.4 mg/kg per day) for 12 days. We studied the development of hypertension (by tail cuff plethysmography), cardiac hypertrophy (by M-mode echocardiography, cardiomyocyte cross-sectional area, and quantitative real-time polymerase chain reaction (qRT-PCR) analysis of hypertrophy marker genes), and fibrosis (by picrosirius red collagen staining and qRT-PCR analysis of fibrosis marker genes) in mice receiving angiotensin II. We found that angiotensin II infusion upregulated MMP-2 concurrent with the development of hypertension, hypertrophy, and fibrosis. This upregulation of MMP-2 depended on MMP-7 and TACE (tumor necrosis factor-α convertase, ADAM-17). RNA interference targeting MMP-7 and TACE attenuated the angiotensin II-induced upregulation of MMP-2 and prevented the development of hypertension, as well as development of cardiac hypertrophy and fibrosis. In contrast, pharmacological inhibition and RNA interference of MMP-2 attenuated angiotensin II-induced hypertension, without influencing development of cardiac hypertrophy or fibrosis. Downstream of MMP-7 and TACE, MMP-2 mediated angiotensin II-induced hypertension, but did not mediate cardiac hypertrophy or fibrosis. This suggests a functional specialization of MMP-2 in agonist-induced cardiovascular disease development that has potential implications for the design of metalloproteinase-based therapeutic strategies.

Electrocardiograms of collegiate football athletes

BACKGROUND

The prevalence of electrocardiogram (ECG) abnormalities in American collegiate football athletes is virtually unknown.

PURPOSE

The purpose of this study was to characterize the type and frequency of ECG abnormalities in a sample of football athletes entering National Collegiate Athletic Association (NCAA) Division I Football Bowl Subdivision university program.

METHODS

Over a 4-y period, resting and exercise 12-lead ECG recordings were analyzed by a cardiologist from 68 freshmen and 9 transfer football athletes (n=77; 54 African-Americans and 23 Caucasians, aged 18 +/- 1 y, height=1.89 +/- 0.06 m, weight= 104.4 +/- 19.8 kg) as part of their entry physical examination.

RESULTS

A total of 79% of the athletes demonstrated at least 1 abnormal ECG finnding, and significantly more African-America athletes (85%) than Caucasian (65%) athletes. Wolff-Parkinson-White (WPW) syndrome was found in 1 African-American player. Frequencies of various ECG abnormal findings in all athletes were: left ventricular hypertrophy = 64.5%, ST-T wave = 6.5%, interventricular conduction delay = 2.6%, sinus bradycardia = 9.1%, sinus arrhythmia = 15.6%, first-degree atrioventricular (AV) block = 11.7%, left atrial enlargement = 48.1%, early repolarization = 33.8%, and right axis deviation = 20.8%. Average values for the PR (0.17 +/- 0.03 s), QRS (0.08 +/- 0.02 s), and QT intervals (0.38 +/- 0.05 s), P-wave duration (0.10 +/- 0.02 s), and QRS axis (79.1 +/- 18.2 degrees) were normal. The ECG responses to maximal treadmill exercise stress tests were evaluated as normal without ischemia or arrhythmias.

CONCLUSION

Abnormal resting ECG findings are common in a sample of collegiate football athletes, exceeding the rate expected for their age, and are more frequent in African-American athletes as compared with Caucasian athletes.

Functional and metabolic evaluation of the athlete's heart by magnetic resonance imaging and dobutamine stress magnetic resonance spectroscopy

BACKGROUND

The question of whether training-induced left ventricular hypertrophy in athletes is a physiological rather than a pathophysiological phenomenon remains unresolved. The purpose of the present study was to detect any abnormalities in cardiac function in hypertrophic hearts of elite cyclists and to examine the response of myocardial high-energy phosphate metabolism to high workloads induced by atropine-dobutamine stress.

METHODS AND RESULTS

We studied 21 elite cyclists and 12 healthy control subjects. Left ventricular mass, volume, and function were determined by cine MRI. Myocardial high-energy phosphates were examined by 31P magnetic resonance spectroscopy. There were no significant differences between cyclists and control subjects for left ventricular ejection fraction (59+/-5% versus 61+/-4%), left ventricular cardiac index (3.4+/-0.4 versus 3.4+/-0.4 L x min(-1) x m[-2]), peak early filling rate (562+/-93 versus 535+/-81 mL/s), peak atrial filling rate (315+/-93 versus 333+/-65 mL/s), ratio of early and atrial filling volumes (3.0+/-1.0 versus 2.6+/-0.6), mean acceleration gradient of early filling (5.2+/-1.4 versus 5.8+/-1.9 L/s2), mean deceleration gradient of early filling(-3.1 +/- 0.9 versus -3.2 +/- 0.7 L/s2), mean acceleration gradient of atrial filling (3.6+/-1.8 versus 4.5+/-1.7 L/s2), and atrial filling fraction (0.23+/-0.06 versus 0.26+/-0.04, respectively). Cyclists and control subjects showed similar decreases in the ratio of myocardial phosphocreatine to ATP measured with 31P magnetic resonance spectroscopy during atropine-dobutamine stress (1.41+/-0.20 versus 1.41+/-0.18 at rest to 1.21+/-0.20 versus 1.16+/-0.13 during stress, both P=NS).

CONCLUSIONS

Left ventricular hypertrophy in cyclists is not associated with significant abnormalities of cardiac function or metabolism as assessed by MRI and spectroscopy. These observations suggest that training-induced left ventricular hypertrophy in cyclists is predominantly a physiological phenomenon.

The athlete's heart. Historical perspectives--solved and unsolved problems

Clinicians are coming back to Henschen's assessment of the athlete's heart as a physiologic and positive phenomenon. An athlete's heart may be affected by clinical conditions. Regarding the extreme performance of the athlete's heart in training and competition, conditions that may be harmless in sedentary people can be fatal for the athlete. The athlete's heart therefore deserves the particular interest and care of the sports cardiologist.

Bovine vectocardiography: a comparative study relative to the validity of four tridimensional lead systems

For spatial vectocardiography to become applicable for cardiac investigation in cattle, it was necessary to develop a reliable standardized electrocardiographic lead system in this species. In this study, four tridimensional lead systems, initially developed in horses, were compared when applied in calves. Fifty seven electrocardiograms were collected. The between-subject variability of the magnitude and angles of the tridimensional P, QRS and T modal vectors obtained by use of each lead system was compared. Reproducibility of vectrocardiographic measurements was analyzed by comparing results obtained in 10 calves within a one day interval. The Holmes semi-orthogonal lead system, giving the lowest between-subject variability and the highest between-day reproducibility, appeared to be the most reliable lead system in order to apply vectocardiography in the bovine species.

Left ventricular dimensions and mass using magnetic resonance imaging in female endurance athletes

Few published studies of left ventricular (LV) mass in female endurance athletes have been performed with M-mode echocardiography, which involves assumptions of LV geometry. Therefore, magnetic resonance imaging, a 3-dimensional technique, was used to examine LV mass, LV end-diastolic volume and mean wall thickness in female long distance runners (n = 13; mean age 29 years), cyclists (n = 12; mean age 26 years) and cross-country skiers (n = 11; mean age 24 years), and the findings were compared with sedentary control subjects (n = 10; mean age 27 years) matched for height and body weight. The physical characteristics for all subjects included height (mean 166 cm, and body weight (mean 56 kg). The percent body fat (mean 11.7) and maximal oxygen uptake (VO2max, mean 63 ml.kg-1.min-1) were similar (p greater than 0.05) among all athletic groups, but significantly different from the control group (body fat, mean 22.5%; VO2max, mean 35 ml.kg-1.min-1). LV mass (mean 159 kg), LV end-diastolic volume (mean 122 ml), and mean wall thickness (mean 11.5 mm) were also similar among the athletic groups and significantly larger than the following control values: LV mass (mean 115 g), LV end-diastolic volume (mean 93 ml) and mean wall thickness (mean 9.8 mm). Ratios of LV mass to lean body weight were similar among all athletic groups, although athletic groups had larger ratios (p less than 0.05) than the sedentary control subjects. LV mass/LV end-diastolic volume ratio was similar (p greater than 0.05) among all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitral valve prolapse: definition and implications in athletes

Mitral valve prolapse is probably the most common cardiac valve disorder, affecting approximately 5% of the population. Although it is genetically determined, its clinical manifestations do not usually become evident before adulthood. In the setting of a cardiology referral center, a mitral valve prolapse syndrome, consisting of nonspecific symptoms, repolarization changes on the electrocardiogram and arrhythmias, has been identified. However, doubt has recently been expressed about the existence of such a syndrome. The prognosis of mitral valve prolapse is generally favorable but infrequent complications do occur and include transient ischemic attacks, progression of mitral regurgitation with or without ruptured chordae tendineae, infective endocarditis and sudden death. The symptoms and the complications are not usually related to physical activity. A permissive attitude toward participation of patients with mitral valve prolapse in competitive athletics is probably warranted; however, it would appear reasonable to disqualify athletes with mitral valve prolapse in the following circumstances: history of syncope; disabling chest pain; complex ventricular arrhythmias, particularly if induced or worsened by exercise; significant mitral regurgitation; prolonged QT interval; Marfan's syndrome; and family history of sudden death.

Current cardiology problems in sports medicine

The cardiologist involved in the evaluation of the competitive athlete requires knowledge of the normal variations seen on clinical examination and laboratory studies. There is limited information in the literature, currently, that provides guidelines for decision making in the face of cardiac abnormalities. This paper outlines our experience with athletes and cardiac disease. Recommendations are given as guidelines for specific activity allowances.

Electrocardiogram of the athlete: an analysis of 289 professional football players

The electrocardiogram (ECG) of athletes reflects physiologic cardiovascular adaptations that occur in well-conditioned individuals. To more clearly define electrocardiographic changes seen in predominantly power-trained athletes, the ECGs of 289 apparently healthy professional football players were analyzed in detail. The players, aged 21 to 35 years, one-third of whom were black, had a mean body surface area of 2.24 m2, a mean heart rate at rest of 56 +/- 9 beats/min (with 77% (223) having a rate of less than 60 beats/min), and a mean P axis of 30 +/- 25 degrees. A wide QRS-T angle (greater than 60 degrees) was present in 14% (41 players) of the group. The mean PR interval was 0.18 +/- 0.02 second (greater than 0.21 in 9% [26 players]). Although two-thirds of the players had a QRS duration of 0.10 second, only 1 had right bundle branch block and none had left bundle branch block. The sum of S in lead V1 plus R in lead V5 averaged 37 +/- 9 mm, with 35% (101 players) demonstrating voltage criteria for left ventricular hypertrophy. The S + R value varied inversely with weight (r = -0.27, p less than 0.002). The maximum T height in any lead had a mean of 8.6 +/- 3 mm, with 22% (64 players) having a T height greater than or equal to 11 mm. U waves were universally present. ST-T changes mimicking ischemia were noted in 39 of 289 players (13%), 22 (58%) of whom were black (p less than 0.001). The maximal J-point elevation in any lead averaged 1.9 +/- 0.9 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic dimensions and maximal oxygen uptake in oarsmen during training

We studied nine freshmen and 14 senior oarsmen undergraduates during seven months of training and compared them with 17 age and sex-matched sedentary control subjects in order to assess the influence of heavy physical exercise on cardiac dimensions and maximal oxygen uptake. Standard M-mode echocardiographic techniques were used. At the start of the season senior oarsmen had a greater left ventricular end-diastolic dimension, and a thicker interventricular septum and posterior left ventricular wall than control subjects and freshmen oarsmen. The two latter groups did not differ from each other. During the training period there was a slight and gradual increase in left ventricular end-diastolic dimension, and interventricular septum and posterior wall thickness in freshmen. In seniors only left ventricular end-diastolic dimension increased significantly. Maximal oxygen uptake showed a distinct increase between the fourth and seventh month during the period of intensive rowing training. There was no relation between echocardiographic variables and maximal oxygen uptake. A combination of heavy dynamic and static exercise can thus lead to significant changes in both left ventricular wall thickness and chamber size within months. Echocardiographic variables measured at rest cannot be used as a suitable index of performance capacity.

Echocardiography and the Athlete's Heart

In brief: Echocardiographic studies permit direct, accurate measurements of the ventricular wall thickness and cavity diameter. The authors review several of these studies, which show that elite athletes' left ventricles are larger than those of sedentary persons. Left ventricular wall thickness is greater in athletes excelling in sports involving static exercise, whereas those in endurance sports have larger ventricular cavities. These differences in cardiac dimensions may be the result of genetic makeup, prolonged and strenuous training, or a combination of both. Studies of short-term training showed only minor or no changes in left ventricular morphology, although significant improvements in performance and aerobic capacity were reported.

Electrocardiographic and echocardiographic characteristics of long distance runners. Comparison of left ventricular function with age- and sex-matched controls

Nineteen long distance runners and 19 age- and sex-matched sedentary controls were evaluated by echocardiography and electrocardiography (ECG) at rest and after 12 minutes of treadmill exercise. Seven of ten male athletes exhibited ECG abnormalities of prominent precordial voltage, early repolarization, and one had right ventricle hypertrophy; only three of nine females had ECG abnormalities. The resting and postexercise heart rates and blood pressures were lower in athletes than controls (P less than 0.001). The athletes increased their left ventricular end-diastolic volume and stroke volume and had a moderate increase in heart rate. Controls markedly increased only their heart rate to the same level of exercise. One female athlete and one female control had 1 mm of ST segment depression with exercise. The right ventricular wall thickness was equal to or greater than 6 mm in athletes versus equal to or less than 5 mm in controls. The left ventricular wall was thicker in athletes than controls, the resultant left ventricular mass was 60% more in athletes due to left ventricular hypertrophy (P less than 0.001). We concluded left ventricular hypertrophy is present in athletes as a result of endurance running.

Noninvasive diagnosis of the cardiomyopathies

The presenting clinical features of the cardiomyopathies are nonspecific. Echocardiography is useful in detecting patients with cardiomyopathy and determining proper management. Echocardiography can be used to determine both cardiac structural measurements and cardiac function.

Noninvasive evaluation of the athletic heart: sprinters versus endurance runners

To evaluate possible differences in the cardiac effects of different types of running training, 22 competing male runners--10 sprinters and 12 endurance runners--were studied with a physical examination, electrocardiography, chest X-ray film and echocardiography. Thirteen sedentary men served as control subjects. There were no differences between the athletic groups in physical findings. However, left ventricular hypertrophy in the electrocardiogram was more apparent in the endurance runners (P less than 0.05), whose relative heart size on chest X-ray examination was also greater than in the sprinters (P less than 0.02). On echocardiography the left ventricular end-diastolic volume was equally greater than normal in both groups of athletes (P less than 0.005), but in the endurance runners the percent chance of the minor axis diameter in systole was greater than in the sprinters or control subjects (P less than 0.02). Values for left ventricular wall thickness and mass were greater than normal in both groups of athletes but were higher in the endurance runners than in the sprinters (P less than 0.001). The left atrial diameter was apparently greater in the endurance runners than in the sprinters or control subjects (P less than 0.001), whereas that of the sprinters did not differ from normal. Thus, intensive sprinter training seems to dilate the left ventricle but causes less increase in wall thickness and mass than training for endurance running and no change in left ventricular function or left atrial size. Endurance running causes left ventricular dilatation equal to that of sprinter training, greater wall hypertrophy and improved systolic emptying of the left ventricle, and it also dilates the left atrium perhaps because of decreased left ventricular compliance.