Echocardiographic evaluation of long-term effects of exercise on left ventricular hypertrophy and function in professional bicyclists

IGF1-PI3K-induced physiological cardiac hypertrophy: Implications for new heart failure therapies, biomarkers, and predicting cardiotoxicity

Heart failure represents the end point of a variety of cardiovascular diseases. It is a growing health burden and a leading cause of death worldwide. To date, limited treatment options exist for the treatment of heart failure, but exercise has been well-established as one of the few safe and effective interventions, leading to improved outcomes in patients. However, a lack of patient adherence remains a significant barrier in the implementation of exercise-based therapy for the treatment of heart failure. The insulin-like growth factor 1 (IGF1)-phosphoinositide 3-kinase (PI3K) pathway has been recognized as perhaps the most critical pathway for mediating exercised-induced heart growth and protection. Here, we discuss how modulating activity of the IGF1-PI3K pathway may be a valuable approach for the development of therapies that mimic the protective effects of exercise on the heart. We outline some of the promising approaches being investigated that utilize PI3K-based therapy for the treatment of heart failure. We discuss the implications for cardiac pathology and cardiotoxicity that arise in a setting of reduced PI3K activity. Finally, we discuss the use of animal models of cardiac health and disease, and genetic mice with increased or decreased cardiac PI3K activity for the discovery of novel drug targets and biomarkers of cardiovascular disease.

Differences in American Athletes Undergoing Preparticipation Examination by Sex, Participation Level, and Age

OBJECTIVE

To describe the preparticipation examination findings among American athletes by sex, participation level, and age.

DESIGN

Hypothesis-generating retrospective cohort study.

SETTING

Saint-Luke's Athletic Heart Center, Kansas City, Missouri.

PARTICIPANTS

A total of 2954 student athletes.

INTERVENTIONS

Athletes underwent preparticipation examination, which included history and physical, electrocardiogram, and 2-D transthoracic echocardiogram.

MAIN OUTCOME MEASURES

Differences noted on screening preparticipation examination by sex, participation level, and age.

RESULTS

Female athletes reported more symptoms than male athletes (odds ratio [OR] = 1.61; 95% confidence interval [CI], 1.32-1.97; P < 0.0001) but had lower prevalence of abnormal electrocardiogram (OR 0.52; CI, 0.39-0.68; P < 0.0001). College athletes reported fewer symptoms than novice athletes (OR 0.35; CI, 0.29-0.43; P < 0.0001) with no difference in the prevalence of abnormal electrocardiography (ECG) (OR 0.96; CI, 0.73-1.26; P = 0.78). Older athletes reported fewer symptoms than younger athletes (OR 0.61; CI, 0.52-0.71; P < 0.0001) with no difference in the prevalence of abnormal ECG (OR 1.00; CI, 0.81-1.23; P = 0.89). There were 43 athletes with clinically important findings with no difference in prevalence of these findings across sex, participation level, and age.

CONCLUSIONS

Among this American cohort of athletes, male athletes reported fewer symptoms and had higher prevalence of abnormal ECG findings compared with female athletes. College and older athletes reported fewer symptoms and had no difference in prevalence of abnormal ECG findings compared with novice and younger athletes, respectively. Despite these differences between groups, the prevalence of clinically important findings was comparable among groups.

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

Purpose

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

Methods

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

Results

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

Conclusion

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

BRADYCARDIA IN ATHLETES: DOES THE TYPE OF SPORT MAKE ANY DIFFERENCE? – A SYSTEMATIC REVIEW

ABSTRACT Bradycardia in athletes can range from moderate to severe, and the factors that contribute to slow heart rate are complex. Studies investigating the mechanisms associated with this condition are controversial, and may be linked to the form of exercise practiced. A systematic literature review was conducted to discuss bradycardia mechanisms in athletes who practice different forms of sport. The databases consulted were Pubmed (MEDLINE), Clinical Trials, Cochrane, Scopus, Web of Science, SciELO, Sport Discus and PEDro. The search included English language articles published up to January 2019, that evaluated athletes who practiced different forms of sport. One hundred and ninety-three articles were found, ten of which met the inclusion criteria, with 1549 male and female athletes who practiced diverse forms of sport. Resting heart rate and cardiac structure were studied in association with the form of sport practiced, through heart rate variability, electrocardiogram, echocardiogram and pharmacological blockade. The studies suggest that a slow resting heart rate cannot be explained by increased vagal modulation alone, but also includes changes in cardiac structure. According to the studies, different sports seem to produce different cardiac responses, and the bradycardia found in athletes can be explained by non-autonomic and autonomic mechanisms, depending on the type of effort or the form of sport practiced. However, the mechanism underlying the slow heart rate in each form of sport is still unclear. Level of evidence II; Prognostic studies - Investigating the effect of a patient characteristic on the outcome of disease.

Impact of endurance exercise on the heart of cyclists: A systematic review and meta-analysis

OBJECTIVE

To compare heart structure and function in endurance athletes relative to participants of other sports and non-athletic controls in units relative to body size. A secondary objective was to assess the association between endurance cycling and cardiac abnormalities.

PATIENTS AND METHODS

Five electronic databases (CINAHL, Cochrane Library, Medline, Scopus, and SPORTdiscus) were searched from the earliest record to 14 December 2019 to identify studies investigating cardiovascular structure and function in cyclists. Of the 4865 unique articles identified, 70 met inclusion criteria and of these, 22 articles presented 10 cardiovascular parameters in units relative to body size for meta-analysis and five presented data relating to incidence of cardiac abnormalities. Qualitative analysis was performed on remaining data. The overall quality of evidence was assessed using GRADE. Odds ratios were calculated to compare the incidence of cardiac abnormality.

RESULTS

Heart structure was significantly larger in cyclists compared to non-athletic controls for left ventricular: mass; end-diastolic volume, interventricular septal diameter and internal diameter; posterior wall thickness, and end-systolic internal diameter. Compared to high static and high dynamic sports (e.g., kayaking and canoeing), low-to-moderate static and moderate-to-high dynamic sports (e.g., running and swimming) and moderate-to-high static and low-to-moderate dynamic sports (e.g., bodybuilding and wrestling), endurance cyclists end-diastolic left ventricular internal diameter was consistently larger (mean difference 1.2-3.2 mm/m²). Cardiac abnormalities were higher in cyclists compared to controls (odds ratio: 1.5, 95%CI 1.2-1.8), but the types of cardiac abnormalities in cyclists were not different to other athletes.

CONCLUSION

Endurance cycling is associated with a larger heart relative to body size and an increased incidence of cardiac abnormalities relative to controls.

The impact of demographic, anthropometric and athletic characteristics on left atrial size in athletes

The structural adaptations of the “athlete's heart” include left atrial (LA) enlargement. A literature search was performed based on PubMed listings up to November 2, 2019 using “athletes AND left atrium,” “athletes AND LA,” “sports AND left atrium,” “sports AND LA,” “exercise AND left atrium,” and “exercise AND LA” as the search terms. Eligible studies included those reporting the influence of demographic, anthropometric and athletic characteristics on LA size in athletes. A total of 58 studies were included in this review article. Although LA volume has been reported to be greater in males compared to females when indexed for body surface area (BSA), there was no difference between sexes. The positive association between LA size and age in athletes may reflect the increase in body size with maturation in nonadult athletes and the training age of endurance athletic activity in adult athletes. Caucasian and black athletes have been demonstrated to exhibit similar LA enlargement. The positive association of LA size with lean body mass (LBM) possibly accounts for the relationship of LA size with BSA. LA enlargement has been reported only in endurance‐trained, but not in strength‐trained athletes. LA size appears to increase with an increase in both the volume and intensity of endurance training. LA size correlates independently with the training age of endurance athletes. The athlete's characteristics that independently determine LA size include LBM, endurance training, and training age.

Aerobic Training Protects Cardiac Function During Advancing Age: A Meta-Analysis of Four Decades of Controlled Studies

Background

In contrast to younger athletes, there is comparatively less literature examining cardiac structure and function in older athletes. However, a progressive accumulation of studies during the past four decades offers a body of literature worthy of systematic scrutiny.

Objectives

We conducted a systematic review, meta-analysis and meta-regression of controlled echocardiography studies comparing left ventricular (LV) structure and function in aerobically trained older athletes (> 45 years) with age-matched untrained controls, in addition to investigating the influence of chronological age.

Methods

Electronic databases were searched from inception to January 2018 before conducting a random-effects meta-analysis to calculate pooled differences in means, effect size and 95% confidence intervals (CIs). Study heterogeneity was reported using Cochran’s Q and I² statistic.

Results

Overall, 32 studies (644 athletes; 582 controls) were included. Athletes had greater LV end-diastolic diameter (3.65 mm, 95% CI 2.66–4.64), interventricular septal thickness (1.23 mm, 95% CI 0.85–1.60), posterior wall thickness (1.20 mm, 95% CI 0.83–1.56), LV mass (72 g, 95% CI 46–98), LV mass index (28.17 g·m², 95% CI 19.84–36.49) and stroke volume (13.59 mL, 95% CI 7.20–19.98) (all p < 0.01). Athletes had superior global diastolic function [ratio of early (E) to late (A) mitral inflow velocity (E/A) 0.18, 95% CI 0.13–0.24, p < 0.01; ratio of early (e′) to late (a′) diastolic annular tissue velocity (e′/a′) 0.23, 95% CI 0.06–0.40, p = 0.01], lower A (−8.20 cm·s⁻¹, 95% CI −11.90 to −4.51, p < 0.01) and a′ (−0.72 cm·s⁻¹, 95% CI −1.31 to −0.12, p = 0.02), and more rapid e′ (0.96 cm·s⁻¹, 95% CI 0.05–1.86, p = 0.04). Meta-regression for chronological age identified that athlete–control differences, in the main, are maintained during advancing age.

Conclusions

Athletic older men have larger cardiac dimensions and enjoy more favourable cardiac function than healthy, non-athletic counterparts. Notably, the athlete groups maintain these effects during chronological ageing.

Electronic supplementary material

The online version of this article (10.1007/s40279-018-1004-3) contains supplementary material, which is available to authorized users.

Hormonal Response to Incremental and Continuous Exercise in Cyclists with Left Ventricle Hypertrophy

The aim of this study was to assess the effects of incremental and continuous exercise on the concentration of insulin-like growth factor-1 (IGF-1), growth hormone (GH), testosterone (T), and cortisol (C), as well as to investigate whether increased cardiac dimensions in cyclists were related to changes in these hormones and cardiac biomarkers. The study included 30 elite cyclists divided into two groups, i.e., athletes with left ventricle hypertrophy (a LVH group), and a control group (CG) without LVH. The study protocol included performance of a standard incremental exercise (IncEx) test to measure athletes’ maximum power (Pmax), maximum oxygen uptake (VO2max), and lactate threshold (LAT). The IncEx test results were then used to determine the intensity of the continuous exercise (ConEx) test which was performed after the 1-week washout period. Cyclists with LVH and without LVH did not differ in resting hormone concentrations and cardiac biomarkers levels. There was a significant effect of exercise on serum IGF-1 levels (p < 0.05) in the LVH group and a combined effect of the type of exercise and LVH on IGF-1 (p < 0.05). Cyclists with LVH demonstrated higher post exercise T levels recorded in response to exercise compared to the CG (p < 0.01). Significantly higher serum T levels were observed in response to ConEx compared to IncEx in the LVH group and the CG (p < 0.05 and p < 0.05, respectively). In the LVH group, a significant positive correlation between the post-exercise T/C ratio and left ventricular mass index was observed (r = 0.98, p < 0.01). There were no effects of heart hypertrophy on cardiac standard biomarkers. Incremental and continuous exercise caused a marked increase in steroid hormone concentrations and moderate strengthening of insulin growth factors effects. Regular incremental exercise seems to induce beneficial cardiac adaptations via significant increases in the concentration of anabolic factors compared to the same training mode yet with constant exercise intensity.

Cardiac Response to Exercise in Normal Ageing: What Can We Learn from Masters Athletes?

BACKGROUND

Ageing is associated with an inexorable decline in cardiac and vascular function, resulting in an increased risk of Cardiovascular Disease (CVD). Lifestyle factors such as exercise have emerged as a primary therapeutic target in the prevention of CVD, yet older individuals are frequently reported as being the least active, with few meeting the recommended physical activity guidelines. In contrast, well trained older individuals (Masters athletes) have superior functional capacity than their sedentary peers and are often comparable with young non-athletes. Therefore, the 'masters' athlete may be viewed as a unique non-pharmacological model which may allow researchers to disentangle the inexorable from the preventable and the magnitude of the unavoidable 'true' reduction in cardiac function due to ageing.

CONCLUSION

This review examines evidence from studies which have compared cardiac structure and function in well trained older athletes, with age-matched controls but otherwise healthy.

Prevalence and significance of isolated T wave inversion in 1755 consecutive American collegiate athletes

BACKGROUND

We evaluated the prevalence of isolated T-wave inversions (TWI) in American athletes using contemporary ECG criteria. Ethnic and gender disparities including the association of isolated TWI with underlying abnormal cardiac structure are evaluated.

METHODS

From 2004 to 2014, 1755 collegiate athletes at a single American university underwent prospective collection of medical history, physical examination, 12-lead ECG, and 2-dimensional echocardiography. ECG analysis was performed to evaluate for isolated TWI as per contemporary ECG criteria.

RESULTS

The overall prevalence of isolated TWI is 1.3%. Ethnic and gender disparities are not observed in American athletes (black vs. white: 1.7% vs. 1.1%; p=0.41) (women vs. men: 1.5% vs. 1.1; p=0.52). No association was found with underlying cardiomyopathy.

CONCLUSION

A lower prevalence of isolated TWI in American athletes than previously reported. Isolated TWI was not associated with an abnormal echocardiogram. No ethnic or gender disparity is seen in American college athletes.

Long-term follow-up of former world-class swimmers: evaluation of cardiovascular function

There is some evidence that long-term high-intensity endurance training might be associated with deterioration in cardiac function and might impose a potential risk for cardiovascular events. Thus, the intention was to retrospectively evaluate the cardiac status in former endurance athletes, particularly right ventricular (RV) dimension and function, to reveal potential cardiac damage. A group of 12 former world-class swimmers (45 ± 1.5 years) was examined 24.9 ± 4.3 years after cessation of high-intensity endurance training. They underwent history taking, physical examination, ECG, exercise testing and echocardiography. Furthermore, functional and echocardiography data that were also available from former evaluations were included in the analysis. There was a significant decline in exercise capacity. LV function was normal with a decrease in septal thickness to 9.1 ± 1.3 (p < 0.05) and LV diastolic diameter to 48.9 ± 5.6 (p < 0.05). Still, there was a remaining septal hypertrophy. RV function was 55.3 ± 4.2% and there were normal RV dimensions adjusted for body surface area. 25 years after the cessation of endurance training there was a normal RV and LV function with a normalization of almost all diameters, still there was a mild LV hypertrophy in some athletes. Consequently, no relevant long-term cardiac remodeling after intensive endurance training was depicted in this group of athletes.

Molecular basis of physiological heart growth: fundamental concepts and new players

The heart hypertrophies in response to developmental signals as well as increased workload. Although adult-onset hypertrophy can ultimately lead to disease, cardiac hypertrophy is not necessarily maladaptive and can even be beneficial. Progress has been made in our understanding of the structural and molecular characteristics of physiological cardiac hypertrophy, as well as of the endocrine effectors and associated signalling pathways that regulate it. Physiological hypertrophy is initiated by finite signals, which include growth hormones (such as thyroid hormone, insulin, insulin-like growth factor 1 and vascular endothelial growth factor) and mechanical forces that converge on a limited number of intracellular signalling pathways (such as PI3K, AKT, AMP-activated protein kinase and mTOR) to affect gene transcription, protein translation and metabolism. Harnessing adaptive signalling mediators to reinvigorate the diseased heart could have important medical ramifications.

Usefulness of two-dimensional and speckle tracking echocardiography in "Gray Zone" left ventricular hypertrophy to differentiate professional football player's heart from hypertrophic cardiomyopathy

Distinguishing the pathologic hypertrophy of hypertrophic cardiomyopathy (HC) from the physiologic hypertrophy of professional football players (PFP) can be challenging when septal wall thickness falls within a "gray zone" between 12 and 16 mm. It was hypothesized that 2-dimensional and speckle-tracking strain (ε) echocardiography could differentiate the hearts of PFPs from those of patients with HC with similar wall thicknesses. Sixty-six subjects, including 28 professional American football players and 21 patients with HC, with septal wall thicknesses of 12 to 16 mm, along with 17 normal controls, were studied using 2-dimensional echocardiography. Echocardiographic parameters, including modified relative wall thickness (RWT; septal wall thickness + posterior wall thickness/left ventricular end-diastolic diameter) and early diastolic annular tissue velocity (e'), were measured. Two-dimensional ε was analyzed by speckle tracking to measure endocardial and epicardial longitudinal ε and circumferential ε and radial cardiac ε. Septal wall thickness was higher in patients with HC than in PFPs (14.7 ± 1.1 vs 12.9 ± 0.9 mm, respectively, p <0.001), while posterior wall thickness showed no difference. RWT was larger in patients with HC than in PFPs (0.68 ± 0.10 vs 0.48 ± 0.06, p <0.001). Longitudinal endocardial ε and radial cardiac ε were significantly higher in PFPs than in patients with HC, while circumferential endocardial ε was no different. RWT was the parameter that most accurately differentiated PFPs from patients with HC. An RWT cut point of 0.6 differentiated PFPs from patients with HC, with an area under the curve of 0.97. In conclusion, a 2-dimensional echocardiographic measure of RWT (septal wall + posterior wall thickness/left ventricular end-diastolic dimension) accurately differentiated PFPs' hearts from those of patients with HC when septal wall thickness was in the gray zone of 12 to 16 mm. Two-dimensional strain analysis identifies variations in myocardial deformation between PFPs and patients with HC with gray-zone hypertrophy.

Exercise, heart and health

Regular physical activity provides a variety of health benefits, including improvement in cardiopulmonary or metabolic status, reduction of the risk of coronary artery disease or stroke, prevention of cancer, and decrease in total mortality. Exercise-related cardiac events are occasionally reported during highly competitive sports activity or vigorous exercises. However, the risk of sudden death is extremely low during vigorous exercise, and habitual vigorous exercise actually decreases the risk of sudden death during exercise. The cause of sudden death is ischemic in older subjects (≥35 years old), while cardiomyopathies or genetic ion channel diseases are important underlying pathology in younger (<35 years old) victims. The subgroup of patients who are particularly at higher risk of exercise-related sudden death may be identified in different ways, such as pre-participation history taking, physical examination and/or supplementary cardiac evaluation. Limitations exist because current diagnostic tools are not sufficient to predict a coronary artery plaque with potential risk of disruption and/or an acute thrombotic occlusion. Proper and cost-effective methods for identification of younger subjects with cardiac structural problems or genetic ion channel diseases are still controversial.

Long-term clinical consequences of intense, uninterrupted endurance training in olympic athletes

OBJECTIVES

The aim of this study was to assess incidence of cardiac events and/or left ventricular (LV) dysfunction in athletes exposed to strenuous and uninterrupted training for extended periods of time.

BACKGROUND

Whether highly intensive and uninterrupted athletic conditioning over a long period of time might be responsible for cardiac events and/or LV dysfunction is unresolved.

METHODS

We assessed clinical profile and cardiac dimensions and function in 114 Olympic athletes (78% male; mean age 22 +/- 4 years), free of cardiovascular disease, participating in endurance disciplines, who experienced particularly intensive and uninterrupted training for 2 to 5 consecutive Olympic Games (total, 344 Olympic events), over a 4- to 17-year-period (mean 8.6 +/- 3 years).

RESULTS

Over the extended period of training and competition, no cardiac events or new diagnoses of cardiomyopathies occurred in the 114 Olympic athletes. Global LV systolic function was unchanged (ejection fraction: 62 +/- 5% to 63 +/- 5%; p = NS), and wall motion abnormalities were absent. In addition, LV volumes (142 +/- 26 ml to 144 +/- 25 ml; p = 0.52) and LV mass index (109 +/- 21 g/m(2) to 110 +/- 22 g/m(2); p = 0.74) were unchanged, and LV filling patterns remained within normal limits, although left atrial dimension showed a mild increase (37.8 +/- 3.7 mm to 38.9 +/- 3.2 mm; p < 0.001).

CONCLUSIONS

In young Olympic athletes, extreme and uninterrupted endurance training over long periods of time (up to 17 years) was not associated with deterioration in LV function, significant changes in LV morphology, or occurrence of cardiovascular symptoms or events.

Cardiac fibrosis in the elderly, normotensive athlete: case report and review of the literature

Background

Cardiac fibrosis occurs with normal aging, but the extent of this process and its effect on cardiac function is unknown. Fibrosis in the nonhypertensive elderly patient is thought to be due to decreased degradation, and not increased deposition, of collagen. The cause of this decreased degradation is unknown. Athletes commonly develop cardiac hypertrophy, and recent evidence has linked long-term physical activity to the development of interstitial myocardial fibrosis. Whether this exercise-induced fibrosis occurs regularly, or only in genetically predisposed individuals, is unknown.

Case presentation

We present the case of an elderly, nonhypertensive athlete who died suddenly of sepsis. Autopsy demonstrated foci of fibrosis throughout the right and left ventricle and significant narrowing of the left ventricular cavity. The findings may be secondary to aging, athletic activity or an undiagnosed medical condition.

Conclusion

The true incidence and importance of age- and exercise-associated myocardial fibrosis is an area for future research.

Biochemical evidence of myocardial fibrosis in veteran endurance athletes

BACKGROUND

Studies on exercise-induced left ventricular hypertrophy (LVH) in veteran athletes suggest the presence of abnormal diastolic filling and incomplete regression of LVH on cessation of exercise.

HYPOTHESIS

Myocardial fibrosis occurs in exercise induced LVH in veteran athletes.

AIM

To document non-invasively the presence of fibrosis in veteran athletes

DESIGN

Prospective case-control study.

SETTING

City centre district general hospital.

PARTICIPANTS

45 normotensive elite veteran athletes and 45 normal sedentary subjects.

INTERVENTIONS

Echocardiographic assessment was made of LV mass, LV systolic and LV diastolic function. Plasma carboxyterminal propeptide of collagen type I (PICP), carboxyterminal telopeptide of collagen type I (CITP) and tissue inhibitor of matrix metalloproteinase type I (TIMP-1) were measured as markers of collagen synthesis, degradation and inhibition of degradation, respectively.

RESULTS

Veteran athletes had significant elevation in LV dimensions and calculated LV mass index (LVMI). Diastolic and systolic function was normal. Plasma PICP (259 vs 166 microg/l, p<0.001), CITP (5.4 vs 2.9 microg/l, p<0.001) and TIMP-1 (350 vs 253 ng/ml, p = 0.01) were elevated in the cohort of athletes. There was a further elevation of TIMP-1 in athletes with echocardiographic LVH, defined as an LVMI >130 g/m(2) (417 vs 266 ng/ml, p = 0.02).

CONCLUSION

There is biochemical evidence of disruption of the collagen equilibrium favouring fibrosis in veteran athletes with LVH. This may suggest that fibrosis occurs as part of the hypertrophic process in veteran athletes.

Preservation of Ventricular Function in Amateur Athletes After Completion of a Marathon

BACKGROUND

Previous studies have demonstrated the development of impaired systolic function and new segmental wall motion abnormalities following completion of ultraendurance events. Limited information is available on the effect of an endurance event such as a marathon on the left ventricular indices and hemodynamics.

METHODS

We examined 45 patients (26 men, 19 women with the average age of 35+/- 8 years) who successfully trained and completed the 2001 Chicago Marathon (26.2 miles). Transthoracic 2-dimensional and Doppler echocardiography (TTE) was preformed prior to the marathon (17+/-10.7 days), immediately following the marathon (71+/-42 minutes), and at follow-up (29+/-12.9 days).

RESULTS

Left ventricular end diastolic volumes declined immediately post marathon and returned to baseline at the one-month follow-up. Ejection fraction was maintained and no regional wall motion abnormalities were identified at any time point. Diastolic parameters decreased immediately post marathon but returned to baseline during follow-up principally reflecting a change in volume status.

CONCLUSION

Marathon running by a group of well-trained recreational athletes does not result in impairment of left ventricular systolic or diastolic function.

Physiological upper limits of ventricular cavity size in highly trained adolescent athletes

OBJECTIVES

To define physiological upper limits of left ventricular (LV) cavity size in trained adolescent athletes.

DESIGN

Cross sectional echocardiographic study.

SETTING

British national sports training grounds and Olympic Medical Institute.

SUBJECTS

900 elite adolescent athletes (77% boys) aged 15.7 (1.2) years participating in ball, racket, and endurance sports and 250 healthy controls matched for age, sex, and size.

MAIN OUTCOME MEASURES

LV end diastolic cavity size.

RESULTS

Compared with controls, athletes had a larger LV cavity (50.8 (3.7) v 47.9 (3.5) mm), a difference of 6%. The LV cavity was > 54 mm in 18% athletes, whereas none of the controls had an LV cavity > 54 mm. The LV cavity exceeded predicted sizes in 117 (13%) athletes. Among the athletes with LV dilatation, 78% were boys, LV size ranged from 52-60 mm, and left atrial diameter and LV wall thickness were enlarged. Systolic and diastolic function were normal. None of the athletes in the study had an LV cavity size > 60 mm. LV cavity size correlated with age, sex, heart rate, and body surface area.

CONCLUSION

Highly trained junior athletes usually have only modest increases in LV cavity size. A proportion of trained adolescent athletes have LV cavity size exceeding predicted values but, in absolute terms, LV cavity rarely exceeds 60 mm as in patients with dilated cardiomyopathy. In highly trained adolescent athletes with an LV cavity size > 60 mm and any impairment of systolic or diastolic function, the diagnosis of dilated cardiomyopathy should be considered.

Patterns of QT dispersion in athletic and hypertensive left ventricular hypertrophy

OBJECTIVE

The objective of this article is to assess whether left ventricular hypertrophy (LVH) due to physical training or of hypertensive patients shows similarities in QT length and QT dispersion.

METHODS

A total of 51 subjects were studied: 17 essential hypertensive patients (27.7 +/- 5.6 years), 17 athletes involved in agonistic activity (canoeing) (24.8 +/- 6.1 years), and 17 normotensive healthy subjects as control group (24.8 +/- 3.6 years). The testing protocol consisted of (1) clinic BP measurement, (2) echocardiography, (3) 12-lead electrocardiographic examination (QT max, QTc max, QT min, QTc min, DeltaQT, DeltaQTc).

RESULTS

There were no significant differences between the body surface area, height, and age of the three groups. Clinic blood pressure was higher in hypertensives (146.5 +/- 45.2/93.5 +/- 4.9 mmHg) versus athletes (120.9 +/- 10.8/77.1 +/- 6.0 mmHg) and controls (123.5 +/- 4.8/78.8 +/- 2.9 mmHg) by definition. Indexed left ventricular mass (LVM/BSA) was significantly greater in both athletes (148.9 +/- 21.1 g/m2) and hypertensives (117.1 +/- 15.2 g/m2) versus controls (81.1 +/- 14.5 g/m2; P < 0.01), there being no statistical difference among them. LVH (LVMI > 125 g/m2) was observed in all athletes, while the prevalence in hypertensives was 50%. In spite of this large difference in cardiac structure there were no significant differences in QT parameters between athletes and the control group, while hypertensive patients showed a significant increase in QT dispersion versus the two other groups (DeltaQT 82 +/- 2.1, 48 +/- 1.3, 49 +/- 2.3 ms; P < 0.01; DeltaQTc 88 +/- 2.0, 47 +/- 1.4, 54 +/- 2.7; P < 0.01).

CONCLUSIONS

LVH induced by physical training activity is not associated with an increase in QT dispersion, whereas pathological increase in LVM secondary to hypertension is accompanied by an increased QT dispersion.

Myocardial adaptation in different endurance sports: an echocardiographic study

OBJECTIVE

Of this study was to investigate three groups of highly trained competitive endurance athletes consisting of marathon runners, triathletes and cyclists for differences in left ventricular adaptation.

METHODS

25 marathon athletes, 21 triathlon athletes and 38 cyclists underwent a standard echocardiographic and Doppler study.

RESULTS

The left ventricular internal diameter in diastole divided by body surface area was significantly larger in cyclists than in marathon runners (31.6+/-3.0 vs. 30.0+/-2.0 mm/ m2, p < 0.05) but did not differ of that of triathletes. Left ventricular mass was significantly different between marathon runners and triathletes (253.6+/-63.7 vs. 322.0+/-62.1 g, p < 0.005) and between marathon runners and cyclists (253.6+/-63.7 vs. 314.2+/-79.2 g, p < 0.005). Systolic wall stress was significantly different between the marathon runners and the triathletes (88.4+/-11.7 vs. 78.9+/-11.0 g/cm2 p < 0.05). Only a minority of the endurance athletes showed concentric remodeling (7%), whereas a majority showed eccentric remodeling (65%) of the left ventricle. The prevalence of eccentric remodeling was more apparent in cyclists. There were some specific differences in left ventricular diastolic function between the three different endurance sports, but no left ventricular diastolic dysfunction could be detected.

CONCLUSION

There is a sport-specific left ventricular adaptation in endurance athletes. The triathlon heart and the heart of a cyclist differ significantly from a marathon heart.

Serial left ventricular adaptations in world-class professional cyclists

OBJECTIVES

The purpose of this research was to study long-term left ventricular (LV) adaptations in very-high-level endurance athletes.

BACKGROUND

Knowledge of cardiac changes in athletes, who are at particularly high risk of sudden cardiac death, is mandatory to detect hypertrophic cardiomyopathy (HCM) or dilated (DCM) cardiomyopathy.

METHODS

We carried out echocardiographic examinations on 286 cyclists (group A) and 52 matched sedentary volunteers (group C); 148 cyclists participated in the 1995 "Tour de France" race (group A1), 138 in the 1998 race (group A2), and 37 in both (group B).

RESULTS

In groups A, A1, A2, and C, respectively, diastolic left ventricular diameter (LVID) was 60.1 +/- 3.9 mm, 59.2 +/- 3.8 mm, 61.0 +/- 3.9 mm, and 49.0 +/- 4.3 mm (A vs. C and A1 vs. A2, p < 0.0001), and maximal wall thickness (WT) was 11.1 +/- 1.3 mm, 11.6 +/- 1.3 mm, 10.6 +/- 1.1 mm, and 8.6 +/- 1.0 mm (A vs. C and A1 vs. A2, p < 0.0001). Among group A, 147 (51.4%) had LVID >60 mm; 17 of them had also a below normal (<52%) left ventricular ejection fraction (LVEF). Wall thickness exceeded 13 mm in 25 athletes (8.7%) (always <15 mm), 23 with LVID >55 mm. In group B, LVID increased (58.3 +/- 4.8 mm to 60.3 +/- 4.2 mm, p < 0.001) and WT decreased (11.8 +/- 1.2 mm to 10.8 +/- 1.2 mm, p < 0.001) with time.

CONCLUSIONS

Over one-half of these athletes exhibited unusual LV dilation, along with a reduced LVEF in 11.6% (17 of 147), compatible with the diagnosis of DCM. Increased WT was less common (always <15 mm) and scarce without LV dilation (<1%), eliminating the diagnosis of HCM. Serial examinations showed evidence of further LV dilation along with wall thinning. These results might have important implications for screening in athletes.

The ACE/DD genotype is associated with the extent of exercise-induced left ventricular growth in endurance athletes

OBJECTIVES

We studied the impact of the angiotensin-converting enzyme (ACE)/DD genotype on morphologic and functional cardiac changes in adult endurance athletes.

BACKGROUND

Trained athletes usually develop adaptive left ventricular hypertrophy (LVH), and ACE gene polymorphisms may regulate myocardial growth. However, little is known about the impact of the ACE/DD genotype and D allele dose on the cardiac changes in adult endurance athletes. METHODS; Echocardiographic studies (including tissue Doppler) were performed in 61 male endurance athletes ranging in age from 25 to 40 years, with a similar period of training (15.6 +/- 4 h/week for 12.6 +/- 5.7 years). The ACE genotype (insertion [I] or deletion [D] alleles) was ascertained by polymerase chain reaction (DD = 27, ID = 31, and II = 3). Athletes with the DD genotype were compared with their ID counterparts.

RESULTS

The DD genotype was associated with a higher left ventricular mass index (LVMI) than the ID genotype (162.6 +/- 36.5 g/m(2) vs. 141.6 +/- 34 g/m(2), p = 0.031), regardless of other confounder variables. As a result, 70.4% of DD athletes and only 42% of ID athletes met the criteria for LVH (p = 0.037). Although systolic and early diastolic myocardial velocities were similar in DD and ID subjects, a more prolonged E-wave deceleration time (DT) was observed in DD as compared with ID athletes, after adjusting for other biologic variables (210 +/- 48 ms vs. 174 +/- 36 ms, respectively; p = 0.008). Finally, a positive association between DT and myocardial systolic peak velocity (medial and lateral peak S(m)) was only observed in DD athletes (p = 0.013, r = 0.481).

CONCLUSIONS

The ACE/DD genotype is associated with the extent of exercise-induced LVH in endurance athletes, regardless of other known biologic factors.

Left atrial and ventricular dimensions in highly trained cyclists

OBJECTIVES

This study sought to investigate the development of left ventricular remodeling during active cycling.

METHODS

A group of 17-year-old (+/- 0.2 years) highly trained competitive cyclists (group I, n = 66) and a group of 29-year old (+/- 2.6 years) professional cyclists (group II, n = 35) underwent two-dimensional (2D) echocardiography. Data from groups I and II were compared with values of normal untrained subjects based on the literature.

RESULTS

Left atrial dimensions were significantly increased in group II as compared to group I (44 +/- 5 vs. 36 +/- 4 mm, p < 0.005). Left ventricular end diastolic diameter was significantly increased in group II as compared to group I (61 +/- 5 vs. 54 +/- 6 mm, p < 0.005). Left ventricular mass was also significantly increased in group II as compared to group I (321 +/- 77 vs. 246 +/- 59 g, p < 0.005). Wall stress showed a significant inverse relation: 104 +/- 42 mmHg in group I vs. 83 +/- 14 mmHg in group II (p < 0.005). The early filling phase of the left ventricular inflow was significantly larger in both athlete groups in relation to the normal value. The E-wave in the athletes compared to the E-wave in normal subjects was 0.87 +/- 0.17 vs. 0.71 +/- 0.14 m/s in group I, p < 0.005, 0.82 +/- 0.17 vs. 0.71 +/- 0.14 m/s in group II, p < 0.05. Late filling phase and the ratio of the diastolic filling pattern did not show significant differences between the two groups.

CONCLUSIONS

Left atrial and left ventricular remodeling starts early in the athlete's career. Athletes of 17 years of age already show significant left atrial and left ventricular dilatation compared to data of untrained subjects described in literature. The process of dilatation continues during the athlete's career. Also left ventricular mass is increased at a young age which continues for several years. More than 60% of the athletes in both groups demonstrated an intermediate form of left ventricular hypertrophy. Diastolic function of the left ventricle remains normal during a long period of athletic career performance.

Resistance training and cardiac hypertrophy: unravelling the training effect

Resistance training (RT) is a popular method of conditioning to enhance sport performance as well as an effective form of exercise to attenuate the age-mediated decline in muscle strength and mass. Although the benefits of RT on skeletal muscle morphology and function are well established, its effect on left ventricular (LV) morphology remains equivocal. Some investigations have found that RT is associated with an obligatory increase in LV wall thickness and mass with minimal alteration in LV internal cavity dimension, an effect called concentric hypertrophy. However, others report that short- (<5 years) to long-term (>18 years) RT does not alter LV morphology, arguing that concentric hypertrophy is not an obligatory adaptation secondary to this form of exertion. This disparity between studies on whether RT consistently results in cardiac hypertrophy could be caused by: (i) acute cardiopulmonary mechanisms that minimise the increase in transmural pressure (i.e. ventricular pressure minus intrathoracic pressure) and LV wall stress during exercise; (ii) the underlying use of anabolic steroids by the athletes; or (iii) the specific type of RT performed. We propose that when LV geometry is altered after RT, the pattern is usually concentric hypertrophy in Olympic weightlifters. However, the pattern of eccentric hypertrophy (increased LV mass secondary to an increase in diastolic internal cavity dimension and wall thickness) is not uncommon in bodybuilders. Of particular interest, nearly 40% of all RT athletes have normal LV geometry, and these athletes are typically powerlifters. RT athletes who use anabolic steroids have been shown to have significantly higher LV mass compared with drug-free sport-matched athletes. This brief review will sort out some of the factors that may affect the acute and chronic outcome of RT on LV morphology. In addition, a conceptual framework is offered to help explain why cardiac hypertrophy is not always found in RT athletes.

Physiologic limits of left ventricular hypertrophy in elite junior athletes: relevance to differential diagnosis of athlete's heart and hypertrophic cardiomyopathy

OBJECTIVES

The present study was undertaken to define physiologic limits of left ventricular hypertrophy in elite adolescent athletes.

BACKGROUND

Systematic sports training may cause increased left ventricular wall thickness (LVWT), creating uncertainty regarding the differential diagnosis of athlete's heart from hypertrophic cardiomyopathy (HCM). This distinction is crucial because HCM is responsible for about one-third of all sudden deaths in young athletes. Echocardiographic data defining athlete's heart are limited largely to adults, with little information specifically in adolescent athletes (14 to 18 years old), for whom the risk of sudden death from HCM is highest.

METHODS

Seven hundred and twenty elite adolescent athletes (75% male) aged 15.7 +/- 1.4 years participating in ball, racket, and endurance sports and 250 healthy sedentary controls of similar age, gender, and body surface area underwent echocardiography.

RESULTS

Compared with controls, athletes had greater absolute LVWT (9.5 +/- 1.7 mm vs. 8.4 +/- 1.4 mm; p < 0.0001). Maximal LVWT exceeded predicted upper limits in 38 athletes (5%); however, no female athlete had a LVWT >11 mm and only three trained male athletes had absolute LVWT >12 mm (0.4%). Each of the 38 athletes with a LVWT exceeding predicted limits also showed enlarged left ventricular cavity dimension (54.4 +/- 2.1 mm; range 52 to 60 mm).

CONCLUSIONS

Trained adolescent athletes demonstrated greater absolute LVWT compared with nonathletes. Only a small proportion of athletes exhibited a LVWT exceeding upper limits, very rarely >12 mm, and then always with chamber enlargement. Hypertrophic cardiomyopathy should be considered strongly in any trained adolescent male athlete with LVWT >12 mm (females >11 mm) and nondilated left ventricle.

Effects of athletic training on heart rate variability triangular index

The purpose of this study was to assess the heart rate variability triangular index (HRVI) in elite track and field athletes. Sixty healthy males (mean aged 22.1 +/- 3.5 years) -15 long distance runners (group A), 15 speed runners (Group B), 15 throwers (Group C) and 15 non-trained subjects (Group D) were submitted to spiroergometric test, m-mode echocardiography and 24-h ambulatory ECG monitoring. The HRVI, mean heart rate, mean interval between two consecutive R waves of the QRS complexes (R-R interval) and standard deviation of the R-R (SDRR) were assessed through time domain method on computed 24-h Holter recordings. The HRVI and the SDRR were 62.2 +/- 9.6 and 220 +/- 40 ms correspondingly in group A, 52.7 +/- 6.0 and 210 +/- 40 ms in B, 44.5 +/- 5.3 and 180 +/- 40 ms in C, 39.3 +/- 6.4 and 180 +/- 30 ms in D. The HRVI and the mean R-R were found to differ statistically between groups A, B and C versus D (P < 0.05). However, the higher value in HRVI was found in group A. Maximal oxygen consumption (VO2max) was 62.0 +/- 4.4 ml kg-1 min-1 in group A, 52.7 +/- 6.0 in group B, 44.6 +/- 5.3 in C and 41.6 +/- 6.0 in D. The higher value in VO2max was also found in group A. The left ventricular mass index (LVMI) and end-diastolic volume index (EDVI) were 136 g m-2 and 83 ml m-2 correspondingly in group A, 136 and 79 in B, 124 and 56 in C and 88 and 55 in group D. The HRVI was found to have a significant relationship with VO2max and EDVI only in group A. On the other hand, no significant relationships were found between HRVI and LVMI in all groups. It is concluded, that the enhanced HRVI in athletes is affected by exercise training pattern. Moreover, HRVI depends on the level of VO2max in endurance-trained, but is independent from the extent of myocardial hypertrophy in all types of training.

Physiology of professional road cycling

Professional road cycling is an extreme endurance sport. Approximately 30000 to 35000 km are cycled each year in training and competition and some races, such as the Tour de France last 21 days (approximately 100 hours of competition) during which professional cyclists (PC) must cover >3500 km. In some phases of such a demanding sport, on the other hand, exercise intensity is surprisingly high, since PC must complete prolonged periods of exercise (i.e. time trials, high mountain ascents) at high percentages (approximately 90%) of maximal oxygen uptake (VO2max) [above the anaerobic threshold (AT)]. Although numerous studies have analysed the physiological responses of elite, amateur level road cyclists during the last 2 decades, their findings might not be directly extrapolated to professional cycling. Several studies have recently shown that PC exhibit some remarkable physiological responses and adaptations such as: an efficient respiratory system (i.e. lack of 'tachypnoeic shift' at high exercise intensities); a considerable reliance on fat metabolism even at high power outputs; or several neuromuscular adaptations (i.e. a great resistance to fatigue of slow motor units). This article extensively reviews the different responses and adaptations (cardiopulmonary system, metabolism, neuromuscular factors or endocrine system) to this sport. A special emphasis is placed on the evaluation of performance both in the laboratory (i.e. the controversial Conconi test, distinction between climbing and time trial ability, etc.) and during actual competitions such as the Tour de France.

Athlete's heart electrocardiogram mimicking hypertrophic cardiomyopathy

Highly trained athletes show a variety of electrocardiographic (ECG) changes, including a striking increase of R or S wave voltage, either flat or deeply inverted T waves, and deep Q waves, that suggest the presence of structural cardiovascular disease, such as hypertrophic cardiomyopathy or arrhythmogenic right ventricular cardiomyopathy, which represent the most common causes of sudden death in young competitive athletes. Despite a number of previous observational surveys, the determinants and clinical significance of these abnormal ECG patterns in trained athletes are still uncertain. Therefore, ECG patterns were compared with cardiac morphology (by echocardiography) in a large population of 1005 athletes, who were engaged in a variety of 38 sporting disciplines. We found abnormal ECGs in 40% of our athletes, but structural cardiac diseases were identified in only 5%. In the absence of cardiac disease, other determinants were recognized as responsible for abnormal ECG patterns, including the extent of morphologic cardiac remodeling, participation in an endurance type of sport, and male gender. Finally, a small but important subset of athletes showed striking ECG abnormalities that strongly suggested the presence of cardiovascular disease in the absence of pathologic cardiac conditions or morphologic changes, suggesting that these ECG alterations may be the consequence of athletic conditioning itself.

Effects of 16 weeks of resistance training on left ventricular morphology and systolic function in healthy men >60 years of age

Resistance training (RT) has gained popularity as an effective form of exercise for older adults. However, the effects of RT on left ventricular (LV) morphology and systolic function in older persons is not well known. The purpose of this study was to assess the effects of 16 weeks of RT on LV morphology and systolic function in healthy older men. Subjects were randomly assigned into a RT group (n = 10; mean+/- SD age, 68 +/- 3 years) or a nonexercise control group (n = 10; age 68 +/- 4 years). RT was performed 3 times per week for 16 weeks at a mean intensity between 60% and 80% of 1 repetition maximum. Leg and bench press 1 repetition maximum and 2-dimensional echocardiography were performed at baseline and after 4, 8, 12, and 16 weeks of training in the RT group. Sixteen weeks of RT was associated with an increase in leg press maximal strength (baseline, 285 +/- 48 kg; after 16 weeks, 367 +/- 47 kg; p <0.05) and bench press maximal strength (baseline, 59 +/- 11 kg; after 16 weeks, 69 +/- 11 kg; p <0.05). No change in leg press maximal strength (baseline, 291 +/- 59 kg; after 16 weeks, 290 +/- 53 kg; p >0.05) or bench press maximal strength (baseline, 60 +/- 9 kg; after 16 weeks, 61 +/- 13 kg; p > .05) was found in control subjects during the same time. RT was not associated with changes in LV cavity size, wall thickness, mass, or systolic function after 4, 8, 12, and 16 weeks of exercise. Thus, 16 weeks of RT was sufficient to increase leg press and bench press maximal strength but did not alter the size or systolic function of the senescent left ventricle.

Cardiac responses to exercise in competitive child cyclists

PURPOSE

Cardiovascular responses to exercise in highly trained child endurance athletes have not been well-defined. This study compared hemodynamic responses with progressive cycle exercise in seven competitive child cyclists (mean age 11.9 yr) compared with 39 age-matched untrained boys.

METHODS

Doppler echocardiography and gas exchange variables were utilized to assess cardiovascular changes during submaximal and maximal exercise.

RESULTS

Mean VO2max was 60.0 (+/-6.0) and 47.0 (+/-5.8) mL x kg(-1) x min(-1) in the cyclists and nonathletes, respectively. At rest and maximal exercise, the cyclists demonstrated greater stroke index than the untrained subjects (resting mean 59 (+/-6) vs 44 (+/-9) mL x m(-2); maximal mean 76 (+/-6) vs 60 (+/-11) mL x m(-2)), but the ratio of maximal:rest stroke index was similar in both groups (1.31 for cyclists, 1.41 for nonathletes). Both groups showed a plateau in stroke volume beyond low-intensity work levels. No significant difference was observed in maximal arteriovenous oxygen difference.

CONCLUSIONS

These findings indicate that 1) maximal stroke volume is the critical determinant of the high VO2max in child cyclists and 2) factors that influence resting stroke volume are important in defining VO2max differences between child endurance athletes and untrained boys.

Left ventricular morphology in junior and master resistance trained athletes

PURPOSE

The objective of this cross-sectional investigation was to assess the effects of short (< 5 yr) versus long-term (> or = 18 yr) resistance training (RT) on left ventricular (LV) dimensions and mass.

METHODS

The subjects for this study were 20 elite male powerlifters (8 junior athletes [JA], mean +/- SD, age: 21.1 +/- 1.2 yr and 12 master athletes [MA], age: 46.0 +/- 5.5 yr) and 19 age-matched male controls (8 young controls [YC], age: 21.8 +/- 2.8 yr and 11 middle-aged controls [MAC], age: 46.8 +/- 4.4 yr). Two-dimensionally guided transthoracic M-mode echocardiograms were performed at rest to quantify LV systolic and diastolic cavity dimension (LVIDs and LVIDd, respectively), ventricular septal wall thickness (VST), posterior wall thickness (PWT), LV mass (LVM), and LV systolic function as measured as fractional shortening (FS).

RESULTS

Short- or long-term RT was not associated with a significant alteration in LVIDd (JA: 53.2 +/- 4.5 mm, YC: 52.1 +/- 3.7 mm, MA: 53.0 +/- 5.1 mm, MAC: 51.8 +/- 4.4 mm), LVIDs (JA: 33.5 +/- 4.8 mm, YC: 32.9 +/- 3.4 mm, MA: 33.0 +/- 4.4 mm, MAC: 31.4 +/- 3.7 mm), VST (JA: 9.4 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.4 +/- 1.6 mm, MAC: 9.7 +/- 0.9 mm), PWT (JA: 9.2 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.0 +/- 1.1 mm, MAC: 9.5 +/- 1.0 mm), LVM (JA: 184.6 +/- 36.1 g, YC: 179.0 +/- 26.5 g, MA, 183.3 +/- 58.1 g, MAC: 184.1 +/- 38.1 g), or FS (JA: 0.37 +/- 0.1%, YC: 0.37 +/- 0.05%, MA: 0.38 +/- 0.1%, MAC: 0.40 +/- 0.04%).

CONCLUSIONS

These findings suggest that short or long-term RT as performed by elite junior and master powerlifters does not alter LV morphology or systolic function.

Cardiac assessment of veteran endurance athletes: a 12 year follow up study

OBJECTIVES

Sustained aerobic dynamic exercise is beneficial in preventing cardiovascular disease. The effect of lifelong endurance exercise on cardiac structure and function is less well documented, however. A 12 year follow up of 20 veteran athletes was performed, as longitudinal studies in such cohorts are rare.

METHODS

Routine echocardiography was repeated as was resting, exercise, and 24 hour electrocardiography.

RESULTS

Nineteen returned for screening. Mean (SD) age was 67 (6.2) years (range 56-83). Two individuals had had permanent pacemakers implanted (one for symptomatic atrial fibrillation with complete heart block, the other for asystole lasting up to 15 seconds). Only two athletes had asystolic pauses in excess of two seconds compared with seven athletes in 1985. Of these seven, five had no asystole on follow up. Two of these five had reduced their average running distance by about 15-20 miles a week. One athlete sustained an acute myocardial infarction during a competitive race in 1988. Three athletes had undergone coronary arteriography during the 12 years of follow up but none had obstructive coronary artery disease. Ten of 19 (53%) had echo evidence of left ventricular hypertrophy in 1997 but only two (11%) had left ventricular dilatation. Ten athletes had ventricular couplets on follow up compared with only two in 1985.

CONCLUSIONS

Although the benefits of moderate regular exercise are undisputed, high intensity lifelong endurance exercise may be associated with altered cardiac structure and function. These adaptations to more extreme forms of exercise merit caution in the interpretation of standard cardiac investigations in the older athletic population. On rare occasions, these changes may be deleterious.

Cardiovascular adaptations to endurance training and detraining in young and older athletes

In order to evaluate the influence of aging on cardiovascular adaptations to endurance training and detraining, 12 young (range 19-25 years) and 12 older (range 50-65 years) male cyclists were examined during the training and after 2 months of detraining. Twelve young and 12 older healthy sedentary males matched for age and body surface area were used as control groups. Each subject underwent a maximal exercise test using a cycle-ergometer in order to measure maximum oxygen consumption, an M-mode and 2D echocardiography in order to assess left ventricle morphology and systolic function, and a Doppler echocardiography for evaluating the diastolic filling pattern. During the training period both groups of athletes showed higher values of maximum oxygen consumption, left ventricular wall thicknesses, end-diastolic diameter and volume, as well as left ventricular mass, than their control subjects; in the older subjects the adaptation of the heart to aerobic training seems to be obtained mainly through a higher increase in left ventricular diastolic filling. In both groups no significant modifications in the ejection fraction and diastolic function parameters were recorded. After the detraining period the wall thicknesses decreased only in young athletes, while left ventricular mass and end-diastolic diameter and volume reduced only in older athletes. In conclusion, training and detraining induced nearly similar left ventricular morphological modifications in the two age groups, even though greater in the older athletes with respect to the ventricular mass and volume. No relevant differences were observed in the Doppler filling pattern between athletes and sedentary controls.

Intensive training and cardiac autonomic control in high level athletes

PURPOSE

We aimed to evaluate in a longitudinal study the effect of intensive training on cardiac autonomic control in athletes using 24-h heart rate variability analysis.

METHODS

Time and frequency domain measures of heart rate variability were calculated from 24-h Holter monitoring in 15 high level bicyclists (mean age 21 +/- 4 yr) after 1 month of detraining and after 5 months of vigorous training. At the same times echocardiographic left ventricular mass and dimensions and maximal oxygen consumption (VO2max) were assessed.

RESULTS

In detrained athletes, VO2max values, left ventricular mass and dimensions, and time and frequency domain measures of vagal modulation of heart rate were higher than in a group of untrained subjects of similar age while heart rate and the low-to-high frequency ratio were lower, indicating an enhanced vagal modulation of heart rate in athletes as compared with that in control subjects. After 5 months of vigorous training, left ventricular mass and dimensions and VO2max increased in athletes, while heart rate decreased further. In contrast, no changes were detectable in time and frequency domain measures of heart rate variability over the entire 24-h and in both waking and sleeping hours.

CONCLUSIONS

This study demonstrates that an increased cardiac vagal control is detectable in detrained athletes; however, after intensive training, despite a significant decrease in heart rate, time and frequency domain measures of heart rate variability reflecting cardiac vagal control remain unchanged. Thus, other mechanisms than changes in cardiac autonomic control could be involved in determining the profound bradycardia of athletes.

The athlete's heart

We have provided an overview of the athlete's heart, focusing on the young athlete. Primary caretakers of athletes should know the major causes of exercise-related cardiac complications and sudden cardiac death and look for these conditions during preparticipation evaluations. We strongly suggest that coaches and other athletic personnel be required to learn basic life support measures such as cardiopulmonary resuscitation (CPR) and to update their skills on an annual basis. Such efforts will help prevent additional exercise-related cardiac deaths.

Differences in myocardial velocity gradient measured throughout the cardiac cycle in patients with hypertrophic cardiomyopathy, athletes and patients with left ventricular hypertrophy due to hypertension

OBJECTIVES

We sought to compare the myocardial velocity gradient (MVG) measured across the left ventricular (LV) posterior wall during the cardiac cycle between patients with hypertrophic cardiomyopathy (HCM), athletes and patients with LV hypertrophy due to systemic hypertension and to determine whether it might be used to discriminate these groups.

BACKGROUND

The MVG is a new ultrasound variable, based on the color Doppler technique, that quantifies the spatial distribution of transmyocardial velocities.

METHODS

A cohort of 158 subjects was subdivided by age into two groups: Group I (mean [+/-SD] 30 +/- 7 years) and Group II (58 +/- 8 years). Within each group there were three categories of subjects: Group Ia consisted of patients with HCM (n = 25), Group Ib consisted of athletes (n = 21), and Group Ic consisted of normal subjects; Group IIa consisted of patients with HCM (n = 19), Group IIb consisted of hypertensive patients (n = 27), and Group IIc consisted of normal subjects (n = 33).

RESULTS

The MVG (mean [+/-SD] s-1) measured in systole was lower (p < 0.01) in patients with HCM (Group Ia 3.2 +/- 1.1; Group IIa 2.9 +/- 1.2) compared with athletes (Group Ib 4.6 +/- 1.1), hypertensive patients (Group IIb 4.2 +/- 1.8) and normal subjects (Group Ic 4.4 +/- 0.8; Group IIc 4.8 +/- 0.8). In early diastole, the MVG was lower (p < 0.05) in patients with HCM (Group Ia 3.7 +/- 1.5; Group IIa 2.6 +/- 0.9) than in athletes (Group Ib 9.9 +/- 1.9) and normal subjects (Group Ic 9.2 +/- 2.0; Group IIc 3.6 +/- 1.5), but not hypertensive patients (Group IIb 3.3 +/- 1.3). In late diastole, the MVG in patients with HCM (Group Ia 1.3 +/- 0.8; Group IIa 1.4 +/- 0.8) was lower (p < 0.01) than that in hypertensive patients (Group IIb 4.3 +/- 1.7) and normal subjects (Group IIc 3.8 +/- 0.9). An MVG < or = 7 s-1, as a single diagnostic approach, differentiated accurately (0.96 positive and 0.94 negative predictive value) between patients with HCM and athletes when the measurements were taken during early diastole.

CONCLUSIONS

In both age groups, the MVG was lower in both systole and diastole in patients with HCM than in athletes, hypertensive patients or normal subjects. The MVG measured in early diastole in a group of subjects 18 to 45 years old would appear to be an accurate variable used to discriminate between HCM and hypertrophy in athletes.

The morphologic consequences of systemic training

The development of echocardiography in the 1970s led to the flourishing of the study of the athlete's heart. From the earliest studies, it was apparent that athletes develop enlargement of the left ventricular cavity and thickening of myocardium in response to prolonged repetitive training. The changes in echocardiographic measurements are small and often within quoted normal ranges. By comparison to sedentary controls, however, left ventricular end-diastolic dimension is increased by approximately 10%, posterior wall dimension by 15% to 20%, and calculated mass by up to 45%.

Impact of different sports and training on cardiac structure and function

There is overwhelming evidence, particularly from echocardiography, that the heart of competitive athletes may differ from that of nonathletes, matched for age, gender, and body size. A larger left ventricular mass has been shown in athletes performing predominantly dynamic aerobic and anaerobic sports, in athletes engaged in static training, and in players of ball sports. Enlargement of the left ventricular internal diameter was most pronounced and reached about 10% in athletes performing predominantly dynamic sports; mainly strength training athletes had a lesser increase of the internal dimension, which was limited to 2.5%. Also the left ventricular wall appeared to be thickened in all types of athletes compared with controls. In sports with high dynamic and low static demands, wall thickness was proportionate or slightly disproportionate to the size of the internal diameter so that relative wall thickness was not different from controls or slightly increased (predominantly eccentric hypertrophy). In strength athletes, the disproportionate increase of wall thickness averaged about 12% (predominantly concentric hypertrophy). In sports with high dynamic and high static demands and requiring prolonged training, such as cycling, the increases of absolute and relative wall thickness reached 29% and 19% and were more pronounced than in runners (mixed hypertrophy). A plausible interpretation of these results is that the development of so-called eccentric or concentric left ventricular hypertrophy according to the type of sports cannot be regarded as an absolute or dichotomous concept because training regimens and sports activities are not exclusively dynamic or static and because the load on the heart is not purely of the volume or the pressure type. Most studies agree that left ventricular systolic and diastolic function is normal in the athlete at rest, whereas diastolic function seems to be enhanced in the exercising endurance athlete. The consistency of the results of studies on athletes in the competitive and the resting season, of training of sedentary subjects, and of spinal cord-injured patients suggests that variations in physical activity can alter left ventricular structure; genetic factors do not seem to be involved in the size of the left ventricular internal diameter but have to be taken into account to interpret wall thickness.

The heart of the senior oarsman: an echocardiographic evaluation

We evaluated left ventricular mass and function in 15 oarsmen aged 78 (65-82) yr (median and range) and in 15 sedentary males aged 72 (65-81) yr by 2-D and M-mode echocardiography and cycle ergometry. The weekly time spent exercising among the oarsmen was 6 (2-18) h and two of the oarsmen were former national and international champions. The two groups of subjects had similar weight, height, and resting blood pressure. The oarsmen reached a maximal work rate of 142 (117-174) vs 113 (75-150) W for the sedentary group (P < 0.01). The internal diameters of the left ventricle were not significantly different, but the septum and posterior wall thicknesses were larger in the oarsmen (11 (8-20) vs 9 (7-11) mm, and 9 (8-13) vs 8 (7-19) mm, respectively, P < 0.023). Thus, the left ventricular mass index of the oarsmen was 19% larger (127 (101-284) vs 103 (74-134) g.m-2, P < 0.01). Also, the systolic function appeared to be superior in the oarsmen as the fractional shortening was 0.45 (0.28-0.55) vs 0.36 (0.18-0.49) in the controls (P < 0.05). In conclusion, we found that long-term rowing in the senior oarsman is associated with enlarged myocardial wall thickness, a normal systolic function, and a high work capacity.

Prevalence and upper limit of cardiac hypertrophy in professional cyclists

The term athlete's heart refers to an increased left ventricular mass. Few studies have assessed the prevalence and normal upper limit of cardiac hypertrophy in highly trained cyclists and this was the aim of this study. A group of 40 professional road cyclists [mean age 26 (SD 3) years] who had participated in European competitions for 3-10 years, were evaluated at the beginning of the 1992-93 season. Evaluation included a clinical history and physical examination, one and two-dimensional echocardiography, 12-lead resting electrocardiogram and a graded exercise test. Determination of the left ventricular mass index (LVMI) was performed using Devereux's formula with correction for the body surface area. Systolic and diastolic blood pressure were measured at rest and at peak exercise. Of the group 23 cyclists (58%) presented a LVMI greater than 130 g.m-2, 21 cyclists presented a diastolic ventricular thickness equal to or greater than 13 mm, with a superior limit of 19 mm; 3 cyclists presented asymmetrical septum hypertrophy; and the relationship between posterior wall and left ventricular diastolic radius was equal to or greater than 0.45 in 14 cases (35%). Electrocardiographic abnormalities of ST-T segment were seen in only 1 subject. No correlation was found between the degree of ventricular hypertrophy and arterial blood pressure. We concluded that these professional cyclists showed a high prevalence of cardiac hypertrophy (58%). The distribution of this hypertrophy was concentric in 20/33 and asymmetric in 3/23 of the subjects with left ventricular hypertrophy. The electrocardiograms were normal in 98% of the subjects.

Ventricular tachyarrhythmias, myocardial ischemia, and sudden cardiac death in patients with hypertensive heart disease

Hypertensive heart disease is increasingly considered to be a strong and independent risk factor for sudden cardiac death. Ventricular tachyarrhythmias in these patients are common and mainly the result of electrophysiologic abnormalities and increased electrical vulnerability of the hypertrophic myocardium. However, proarrhythmia in the hypertrophic heart often is facilitated and aggravated by electrolyte disturbances, the sympathoadrenergic tone, transient blood pressure crisis, and especially by the occurrence of myocardial ischemia. Myocardial ischemia in the setting of hypertensive heart disease may result from stenotic lesions in large and/or small coronary artery vessels and, in the absence of both, will result from the altered cellular oxygen supply and consumption in the hypertrophic myocardium. Recent studies have shown that acute and transient myocardial ischemia are common in many hypertensives, often fail to be symptomatic, and that the dynamic interaction of left ventricular hypertrophy, transient myocardial ischemia, and ventricular tachyarrhythmias may provide a crucial link for the high incidence of sudden cardiac death in patients with hypertensive heart disease.