The ???Athletic Heart Syndrome???

Abstract

Cardiological findings in athletes are often similar to those observed in clinical cases. Electrocardiographic and cardiac imaging abnormalities as well as physical findings may be the same in both of these groups. Bradycardia and rhythm disturbances are the most common abnormalities in athletes. Most athletes with abnormal electrocardiograms are asymptomatic and numerous investigators have failed to detect heart disease in association with such electrocardiograms. In contrast to cardiac dysfunction observed in clinical cases, enhanced or normal ventricular systolic and diastolic function have been reported in athletes. In endurance athletes, this is associated with very high values for maximal aerobic power (VO2max). Absolute and body size-normalised cardiac dimensions in most athletes do not approach values from chronic disease states, and may not exceed echocardiographic normal limits. In addition, pathological and physiological enlargement appear to be biochemically and functionally different. Myosin ATPase enzyme expression and calcium metabolism are different in rats with pathologically or physiologically induced enlargement. The reported biochemical differences underlie systolic and diastolic dysfunction in pathological enlargement. Conversely, trained rodents and humans have demonstrated enhanced systolic and diastolic function. It is important to note that cardiac enlargement observed in athletes is the result of normal adaptation to physical conditioning and/or hereditary influences. Conversely, pathological changes result from disease processes which can lead in turn to reduced function, morbidity and mortality. Since the mid 1970s echocardiography has been used to compare cardiac dimensions in male endurance- and resistance-trained athletes. A sport-specific profile of eccentric and concentric enlargement has been documented in endurance and resistance athletes, respectively. Subsequent studies of athletes have examined factors such as age, sex and degree of competitive success to determine their contribution to these sport-specific cardiac profiles. Unique athletic subgroups have also been analysed and have included ballet dancers, rowers, basketball players and triathletes. However, there is a paucity of data on cardiac dimensions in female athletes. Finally, physical conditioning studies have also examined echocardiographic dimensions before and after endurance and resistance training. Significant enlargement of internal dimensions, wall thickness or left ventricular mass have been reported but such increases are relatively small and by no means universal. Several conflicting explanations for enlarged cardiac dimensions appear in the literature. Chronic volume and pressure haemodynamic overloading during physical conditioning has been proposed to explain eccentric and concentric cardiac enlargement in endurance- and resistance-trained athletes respectively. However, twin studies suggest that hereditary factors may be important determinants of cardiac dimensions and/or the degree of cardiac adaptabi...

The upper limit of physiological cardiac hypertrophy in elite male and female athletes: the British experience

“…An increased left ventricular mass, associated with an increased internal diameter and wall thickness, is a commonly reported finding in the 'athlete's heart' (George et al 1991). The cardiac remodelling observed in athletes is associated with the specific haemodynamic requirements of the exercise undertaken.…”

“…Following the suggestion of differential cardiac remodelling in response to different types of physical training (Morganroth et al 1975), a large number of cross-sectional studies examining small numbers of athletes from a wide range of sports have been published, reviewed, and subjected to meta-analysis (George et al 1991;Pluim et al 1999). Whilst the majority of previous echocardiographic studies have examined small cohorts of athletes, a landmark paper examining 947 elite Italian athletes from 25 sports was published by Pelliccia et al (1991).…”

Exercise and lifestyle predictors of resting heart rate in healthy young adults

“…Many of these health benefits are mediated by cardiovascular adaptations to a regular exercise program, such that physical exercise is an important component of many types of physical rehabilitation programs, including cardiac rehabilitation (recent examples in [5][6][7]). Regular exercise promotes a wide variety of cardiac adaptations, including in alterations in cardiac excitability [8,9], contractile force [10], stroke and end-diastolic volumes [11,12], and diastolic efficiency [13]. These physiological responses to regular exercise increase cardiac peak function, permitting higher levels of physical work [5,6,[11][12][13].…”

The Upper Limit of Physiological Cardiac Hypertrophy in Elite Male Athletes

“…Sport-specific adaptations and differentiation of an athlete's heart were described 100 years ago (Morganroth et al, 1975;Landry et al, 1985;Hoogsteen et al, 2004). Several studies suggested that the precise alterations in cardiac structure associated with training may differ depending on the type of athletic activity (Pluim et al, 2000;Pelliccia et al, 1996;Landry et al, 1985;George et al, 1991;Pearson et al, 1986).…”