Cardiac tissue Doppler imaging in sports medicine

Echocardiographic reference intervals with allometric scaling of 823 clinically healthy rhesus macaques (Macaca mulatta)

BACKGROUND

Echocardiography is commonly used for assessing cardiac structure and function in various species including non-human primates. A few previous studies reported normal echocardiographic reference intervals of clinically healthy rhesus macaques under sedation. However, these studies were under-powered, and the techniques were not standardized. In addition, body weight, age, and sex matched reference intervals should be established as echocardiographic measurements are commonly influenced by these variables. The purpose of this study was to establish reference intervals for complete echocardiographic parameters based on a large cohort of clinically healthy rhesus macaques with wide ranges of weight and age distributions using allometric scaling.

RESULTS

A total of 823 rhesus macaques (ages 6 months to 31 years old; body weights 1.4 to 22.6 kg) were enrolled. Of these rhesus macaques, 421 were males and 402 were females. They were assessed with a complete echocardiographic examination including structural and functional evaluation under sedation with ketamine hydrochloride. The reference intervals of the key echocardiographic parameters were indexed to weight, age, and sex by calculating the coefficients of the allometric eq. Y = aM^b. On correlation matrix, body weight, age, sex, and heart rate were significantly correlated with various echocardiographic parameters and some of the parameters were strongly correlated with body weight and age. Multiple regression analysis revealed that heart rate and body weight statistically significantly predicted several echocardiographic parameters. Valve regurgitation including tricuspid, aortic, pulmonic, and mitral regurgitations without other cardiac structural and functional abnormalities are common in clinically healthy rhesus macaques under ketamine sedation.

CONCLUSIONS

In this study, the reference intervals of echocardiographic parameters were established by performing complete echocardiographic examinations on a large number of clinical healthy rhesus macaques. In addition, allometric scaling was performed based on their weight, and further indexed to age and sex. These allometrically scaled reference intervals can be used to accurately evaluate echocardiographic data in rhesus macaques and diagnose structural and functional evidence of cardiac disease.

The role of echocardiography in the evaluation of cardiac re-modelling and differentiation between physiological and pathological hypertrophy in teenagers engaged in competitive amateur sports

Aims "Athlete's heart" is a cardiac adaptation to long-term intensive training. The aims of this study were to show the prevalence of left ventricular hypertrophy in teenagers who participate in sports, to define the different types of cardiac re-modelling, and to differentiate between physiological and pathological hypertrophy.

METHOD

Echocardiographic measurements were obtained by M-mode, two dimensional, and Doppler techniques of participants from sports and control groups.

RESULTS

The echocardiographic examinations included 100 healthy teenagers taking part in dynamic sports such as football and basketball and 100 healthy teenagers taking part in static sports such as karate and judo. The control group (n=100) included healthy, sedentary teenagers. Sports participants had significantly higher left ventricular mass when compared with the control group, (p0.05). Respondents from both groups had E/A ratios (transmitral flow velocity ratio)>1, preserved diastolic function, and statistically they did not differ from the control group.

CONCLUSION

Echocardiographic parameters show that physiological hypertrophy and cardiac re-modelling are present in teenagers who play sports. Unexpectedly, the prevalence of concentric and eccentric types of re-modelling is equally possible in the group of static sports participants.

Sudden cardiac death in athletes: where do we stand

We aimed to review the literature to explore the magnitude of sudden cardiac death (SCD) in young athletes. Although SCD in athletes is not a common event, it represents a tragedy of the apparently fit young population. SCD varies according to countries, age groups, and sex. In addition, it varies in the underlying causes and the screening tool. Therefore, we are in need for further research efforts. Guidelines, public and physician awareness, and education regarding the warning signs are integral part in the strategy to reduce SCD tragedy. However, all these requirements raise concern for cost-effectiveness in some countries for proper implementation.

Competitive sports and the heart: benefit or risk?

BACKGROUND

Controversy surrounds the cardiac effects of competitive sports and the athlete's heart. In this review, we present and discuss the main cardiological findings in competitive athletes.

METHOD

Selective review of pertinent literature retrieved by a search with the keywords "athlete's heart," "ECG," "echocardiography," "endurance exercise," "longevity," and others.

RESULTS

Regular exercise leads to functional and structural adaptations that improve cardiac function. Athlete's heart, which develops rarely, is a typical finding in endurance athletes. This condition is characterized by physiological, harmonically eccentric hypertrophy of all cardiac chambers. The athlete's ECG can be used to distinguish physiological, training-related changes from pathological training-unrelated changes. The athlete's heart function is normal at rest and increases appropriately during exercise. The cardiac markers troponin and B-type natriuretic peptide are within the normal range in healthy athletes at rest, but can temporarily be mildly elevated after exhausting endurance-exercise, without evidence of myocardial damage. The epidemiological data suggest that participation in competitive sports increases life expectancy.

CONCLUSION

Competitive exercise does not induce cardiac damage in individuals with healthy hearts, but does induce physiological functional and structural cardiac adaptations which have positive effects on life expectancy.

Cardiovascular health, part 1: preparticipation cardiovascular screening

CONTEXT

Identification of potentially fatal cardiac conditions in otherwise healthy athletes presents a major challenge to the sports medicine community. The requirements for preparticipation screening vary among countries and even from state to state within the United States. The mandated use of an electrocardiogram as a screening implement has provoked international controversy.

EVIDENCE ACQUISITION

Part 1 of this review highlights the current guidelines and controversies surrounding cardiovascular screening, with a focus on the diagnostic challenges associated with identifying athletes with inheritable cardiomyopathies. Data sources were limited to peer-reviewed publications from 1984 to the present.

RESULTS

Preparticipation screening should include at least a history and a physical examination for all athletes, whereas use of an electrocardiogram is still controversial. Diagnosis of inherited cardiomyopathies presents unique challenges, particularly in hypertrophic cardiomyopathy, where many features can mimic those found in the "athlete's heart."

CONCLUSIONS

Recognizing cardiac conditions in athletes that can predispose them to sudden cardiac death or other adverse outcomes is of vital importance, as is the appropriate exclusion of these athletes from competition. Further studies are needed to determine the most efficient and cost-effective means of screening and to increase the sensitivity and specificity of diagnostic testing for inheritable cardiovascular diseases.

Illicit use of androgens and other hormones: recent advances

PURPOSE OF REVIEW

To summarize recent advances in studies of illicit use of androgens and other hormones.

RECENT FINDINGS

Androgens and other appearance-enhancing and performance-enhancing substances are widely abused worldwide. Three notable clusters of findings have emerged in this field in recent years. First, studies almost unanimously find that androgen users engage in polypharmacy, often ingesting other hormones (e.g., human growth hormone, thyroid hormones, and insulin), ergo/thermogenic drugs (e.g., caffeine, ephedrine, and clenbuterol), and classical drugs of abuse (e.g., cannabis, opiates, and cocaine). Second, reports of long-term psychiatric and medical adverse effects of androgens continue to accumulate. In cardiovascular research particularly, controlled studies have begun to supersede anecdotal evidence, strengthening the case that androgens (possibly acting synergistically with other abused drugs) may cause significant morbidity and even mortality. Third, it is increasingly recognized that androgen use may lead to a dependence syndrome with both psychological and physiological origins. Androgen dependence likely affects some millions of individuals worldwide, and arguably represents the least studied major class of illicit drug dependence.

SUMMARY

Given mounting evidence of the adverse effects of androgens and associated polypharmacy, this topic will likely represent an expanding area of research and an issue of growing public health concern.

Strongmen sport is associated with larger absolute heart size and impaired cardiac relaxation

This study was carried out to compare cardiac structure and function and blood lipids among Strongmen, sedentary controls, and marathoners. Echocardiography was performed, and endothelial function, blood lipids and maximal oxygen uptake were measured in 27 Caucasian adult men (8 Strongmen, 10 marathoners, 9 controls). Absolute cardiac size parameters such as left ventricular (LV) diameter and wall thickness of Strongmen were higher (p < 0.05), but relative (body surface area indexed) parameters were not different between controls and Strongmen. In Strongmen, the relative LV diameter (p < 0.05), wall thickness (p < 0.001), and LV mass index (p < 0.01) were lower than in marathoners. The absolute but not relative right ventricular diameter was larger in Strongmen as compared with controls, whereas all of the measured relative cardiac size parameters were higher in marathoners as opposed to in controls. The endothelial function and the ratio of wall thickness to chamber diameter were similar among the groups (p > 0.05). Maximal oxygen uptake of Strongmen was lower than in controls (p < 0.05) and marathoners (p < 0.001). Global diastolic LV function of Strongmen was impaired in comparison to controls (p < 0.05) and marathoners (p < 0.05). Plasma lipids were not different between Strongmen and sedentary controls, but in comparison to runners, Strongmen had higher low-density lipoprotein-cholesterol (p < 0.05) and lower high-density lipoprotein cholesterol (p < 0.01). Participation in Strongmen sport is associated with higher absolute but not relative cardiac size parameters, impaired myocardial relaxation, and low cardiorespiratory fitness. Therefore, Strongmen may demand greater attention as an extreme group of athletes with regard to cardiovascular risk.

The physiological impact of intermittent sequential pneumatic compression (ISPC) leg sleeves on cardiac activity

BACKGROUND

Pneumatic sleeves are widely used in surgery to prevent venous stasis and to improve cardiac function. The aim of this study was to assess the underlying cardiovascular mechanism induced by the activation of intermittent sequential pneumatic compression (ISPC) in healthy volunteers.

METHODS

Twenty male subjects underwent transthoracic echocardiographic and tissue Doppler imaging evaluation before and during the activation ISPC devices. Each patient served as his own control.

RESULTS

Following ISPC activation, there were significant increases in cardiac output (from 5.1 to 5.5 L/min, P < .05) and stroke volume (from 72 to 78 mL, P < .002), as well as ejection fraction, the velocity-time integral of aortic flow, and fractional shortening of the left ventricle. There was no increase in heart rate. Tissue Doppler imaging was compatible with normal cardiac responses. Total peripheral resistance was significantly reduced during ISPC activation.

CONCLUSIONS

The activation of ISPC devices in normal volunteers augmented cardiac output because of increased preload as well as decreased afterload.

Long-term musculoskeletal and cardiac health effects of recreational football and running for premenopausal women

We examined long-term musculoskeletal and cardiac adaptations elicited by recreational football (FG, n=9) and running (RG, n=10) in untrained premenopausal women in comparison with a control group (CG, n=9). Training was performed for 16 months ( approximately 2 weekly 1-h sessions). For FG, right and left ventricular end-diastolic diameters were increased by 24% and 5% (P<0.05), respectively, after 16 months. Right ventricular systolic function measured by tricuspid annular plane systolic excursion (TAPSE) increased (P<0.05) in FG after 4 months and further (P<0.05) after 16 months (15% and 32%, respectively). In RG and CG, cardiac structure, E/A and TAPSE remained unchanged. For FG, whole-body bone mineral density (BMD) was 2.3% and 1.3% higher (P<0.05) after 16 months, than after 4 and 0 months, respectively, with no changes for RG and CG. FG demonstrated substantial improvements (P<0.05) in fast (27% and 16%) and slow (16% and 17%) eccentric muscle strength and rapid force capacity (Imp30ms: 66% and 65%) after 16 months compared with 4 and 0 months, with RG improving Imp30ms by 64% and 46%. In conclusion, long-term recreational football improved muscle function, postural balance and BMD in adult women with a potential favorable influence on the risk of falls and fractures. Moreover, football training induced consistent cardiac adaptations, which may have implications for long-term cardiovascular health.

Doping and effects of anabolic androgenic steroids on the heart: histological, ultrastructural, and echocardiographic assessment in strength athletes

Anabolic androgenic steroids (AAS) are used by some athletes to enhance performance despite the health risk they may pose in some persons. This work was carried out to evaluate the possible structural and functional alterations in the heart using two-dimensional, M-mode, tissue Doppler imaging (TDI) and strain rate imaging (SRI) in athletes using supraphysiological doses of AAS. Additionally, the histological and ultrastructural changes in cardiac muscles of adult albino rats after injection of sustanon, as an example of AAS, were studied. Fifteen male bodybuilders using anabolic steroids constituted group 1, five male bodybuilders who are not using anabolic steroids constituted group 2, and five nonathletic males constituted negative control group (group 3). They were investigated by two-dimensional, M-mode, TDI and SRI. This study was performed on 30 adult albino rats. They were divided into two groups. Group I (Control group) (10) was subdivided into negative control, subgroup 1a (5), and subgroup 1b (5), which received 0.8 ml olive oil intramuscular once a week for 8 weeks. Group II (Experimental group) (20) received sustanon 10 mg/kg intramuscularly once a week for 8 weeks. The heart specimens were prepared for light microscopy and transmission electron microscopy. Echocardiographic results showed that bodybuilders who use steroids have smaller left ventricular dimension with thicker walls, impaired diastolic function, as well as higher peak systolic strain rate in steroid-using bodybuilders as compared to the other two groups. Light microscopy examination of cardiac muscle fibers showed focal areas of degeneration with loss of striations and vacuolation in the experimental group. Ultrastructural examination showed disturbance of the banding pattern of the cardiac muscle fiber with disintegration, loss of striations, dehiscent intercalated disc, and interrupted Z-bands. Administration of supraphysiological doses of AAS caused severe deleterious effects in the myocardium both in athletes and in experimental animals. The SRI shows promise in the early detection of systolic dysfunction in those athletes who use steroids.

Myocardial adaptation and efficiency in response to intensive physical training in elite speedskaters

BACKGROUND

Physiological cardiac adaptations to exercise training resulting in the 'athlete's heart' are well known. Most of these studies, however, were included either those who exercise to exhaustion, non-elite athletes or those who participate primarily in sports requiring extensive weight training. Studies utilizing conventional and tissue Doppler echocardiographic studies in highly competitive elite athletes whose training includes both aerobic and weight training are limited.

AIMS AND METHODS

1) To identify baseline cardiovascular structural and physiologic adaptations present in elite athletes who participate in both endurance aerobic and weight training programs and to compare them to similarly aged sedentary controls. The population includes 24 speedskaters participating in the 2006 Olympic Games and 15 sedentary young subjects. 2) To evaluate possible structural and physiologic cardiac changes following short duration, vigorous exercise. We repeated the baseline echocardiographic protocol in the athletes following a 3000 m sprint conducted at race pace.

RESULTS

Compared to non-athletes, the atrial and left ventricular (LV) volumes at rest were larger in elite athletes. There was enhanced LV diastolic function as manifested by higher early annular (septal and lateral) tissue Doppler velocities (E'): 12.7+/-2.3 vs 11.3+/-1.1 cm/s and 17.4+/-4.7 vs 14.4+/-1.2 cm/s, P=0.025 and 0.020 respectively. Evidence of right ventricular (RV) remodeling included larger basal RV dimensions (38+/-5 vs 32+/-4 mm, P=0.001), attenuated RV systolic function at rest (RV area change 35+/-13% in athletes vs 47+/-11% in controls, P=0.006) and lower RV systolic strain rate (SSR) 1.9+/-0.5 vs 2.9+/-1.1/s, P<0.001). However, there was better right ventricular (RV) diastolic function at rest, E': 13.5+/-3.6 vs 11.1+/-1.5 cm/s (P=0.016). Following exercise, the athletes exhibited augmentation of RV systolic function with increased RV fractional area change (increasing to 43+/-10%, P=0.007) and SSR (2.5+/-1.2/s post-exercise, P=0.038).

CONCLUSION

Participation by world-class speedskaters in a vigorous training regimen results in cardiovascular anatomic and physiologic adaptations. These changes, including cardiac chamber dilatation, enhanced ventricular diastolic function and attenuated resting RV systolic function, are likely adaptive and allow for more efficient energy use at rest and a robust response to demands of exercise.

Sudden cardiac death in young athletes

Although regular aerobic physical activity increases exercise capacity and plays a role in both primary and secondary prevention of a variety of chronic disorders, competitive physical exercise is associated with a significant increase of risk of sudden death in athletes, especially adolescents and young adults. Several pathogenetic mechanisms have been speculated, including silent cardiovascular conditions, mostly cardiomyopathy, premature coronary artery disease and congenital coronary anomalies. Uneventful events, especially commotio cordis, and abuse of unfair and dangerous performance-enhancing drugs, are also claimed as potential causes. Although identification of athletes at major risk and prevention of adverse events seems the more pervasive strategy, guidelines for screening athletes differ widely on international basis and even among the different Sport federations. The aim of this review was to compile the current knowledge on the prevalence and the most common causes of sudden death in sportsmen, providing an overview of the guidelines for pre-participation screening.

The upper limit of physiological cardiac hypertrophy in elite male and female athletes in China

Physiological hypertrophy in response to physical training is important in the differentiation of physiological and pathological left ventricular hypertrophy. The goal of our study was to define the structural characteristics of the heart in Chinese athletes. Between June 2005 and August 2005, 339 (165 male, 174 female) elite Chinese athletes from 19 sports were profiled. Standard two-dimensional guided M-mode and Doppler echocardiography were employed to evaluate left ventricular morphology and function. Of the 165 male athletes, 19 (11.5%) male athletes presented with an LVIDd>or=60 mm, with an upper limit of 65 mm. Only three male athletes presented with wall thickness values>or=13 mm. Eighteen (10.3%) female athletes presented with an LVIDd>or=50 mm, and seven (4.2%) female athletes presented with an LVIDd>or=55 mm, with an upper limit of 62 mm. None were found to have a maximum wall thickness greater than 11 mm. Systolic and diastolic functions were within normal limits for all athletes. Results from the present study suggest that upper normal limits for left ventricular wall thickness and LVIDd are 14 and 65 mm for elite male Chinese athletes, and 11 mm and 62 mm for elite female Chinese athletes. Values in excess of these should be viewed with caution and should prompt further investigation to identify the underlying mechanism for the observed left ventricular hypertrophy.