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Athletic Heart Syndrome

Athlete's Heart

Athletic heart syndrome is a physiological disorder characterized by various structural and functional changes that occur as a response to the athletic activities. Hypertrophy and increased diameter of the left ventricle, increased cardiac output, changes in stroke volume, and several other adaptive mechanisms can manifest as sinus bradycardia, or sometimes even as arrhythmia. The diagnosis is made through an electrocardiography and echocardiography, both of which are able to discriminate athletic heart syndrome from pathological diseases.


Although numerous structural changes occur in athletic heart syndrome, such as hypertrophy of the heart (but mainly of the left ventricle), significant rise in the maximal oxygen uptake, increased stroke volume, and thickening of the myocardium, this phenomenon is considered to be a physiological response that meets the demands of the body to perform the necessary movements and actions [1] [2] [3] [4]. This syndrome is most commonly encountered among athletes who participate in sports that require endurance - triathlon, long-to-middle distance running, speed skating, and cross-country skiing [1]. Because of the heart's increased size, diameter, and the strength with which it expulses blood, one of the most common signs of athletic heart syndrome is sinus bradycardia [1]. Heart rate can be as low as 30 beats per minute on Holter monitoring, or it can go even less than 30 beats during sleep [1]. Sinus arrhythmias are the second important component of the clinical presentation of athletic heart syndrome [1]. First or second degree atrioventricular (AV) blocks, incomplete right bundle branch block (RBBB), extrasystoles, and early repolarization (presenting as ST elevation) are frequent exercise-related findings that are interpreted as physiological [1] [4]. Atrial fibrillation is noticed in aged athletes who were involved in endurance training [1] [4].

Heart Disease
  • This review examines current information regarding the metabolic and electrophysiological differences between the myocardial hypertrophy of heart disease and that associated with athletic training.[ncbi.nlm.nih.gov]
  • Genetic changes in heart disease : Our medical team and other researchers at Stanford continue to identify more genetic mutations, or differences, that cause heart disease.[familyheart.stanford.edu]
  • However, by 1977, the medical journals were already reporting that running did not create an immunity to heart disease, including a study published by Dr. Timothy Noakes entitled, Coronary Heart Disease in Marathon Runners.[philmaffetone.com]
  • September 6, 2014 Heart Disease FAQ Athletic heart syndrome Heart Disease FAQ It is common knowledge that your muscles become stronger and thicker if you exercise them frequently. The same is true of the heart muscle.[cardiophile.org]
  • So large in fact, that it could be mistaken for heart disease. Having a large heart usually a sign of heart disease. However, there are 10 reasons why most researchers don’t think having a large heart is dangerous if you’re an athlete.(1-13) 1.[completehumanperformance.com]
Slow Pulse
  • The two most common findings in trained athletes are bradycardia, or a slow pulse (less than 70 beats per minute), and phasic sinus arrhythmia, a pulse that speeds and slows with respiration.[sportsdoctor.com]
  • The athletic heart may simulate the diseased heart by exhibiting a systolic murmur, a slow pulse rate, a variety of arrhythmias and disturbances of cardiac conduction, elevation of the S-T segments, and cardiac enlargement by x-ray.[longislandsportsmassage.com]


Many studies stress the need for discriminating athletic heart syndrome from pathological conditions that may present in a similar fashion and pose a life-threatening risk -hypertrophic cardiomyopathy, pathologically enlarged left ventricle, Wolff-Parkinson-White syndrome, Brugada syndrome, arrhythmogenic right ventricular dysplasia, and QT syndrome should be included in the differential diagnosis [1] [2] [3] [4] [5]. The physician should obtain a detailed history during which the patient must be asked about the sport he/she is practicing, for how many years, and on what level (amateur or professional). A thorough physical examination should follow, with an emphasis on cardiac auscultation that will almost universally reveal bradycardia at rest. Electrocardiography (ECG) and Holter monitoring are very useful diagnostic modalities that evaluate the cardiac conduction system and determine if any abnormalities are present [1] [4] [6]. As mentioned previously, sinus bradycardia, AV blocks, extrasystoles, and early repolarization are hallmarks of athletic heart syndrome [1] [4]. If, however, ECG reveals left anterior or posterior hemiblocks, complete bundle branch blocks, ventricular preexcitation (an indicator of Wolff-Parkinson-White syndrome), abnormal Q waves, ST depression, or epsilon waves, further evaluation is mandatory [1] [4]. Cardiac ultrasonography is crucial for examining the morphology of the heart and its characteristics and should be used to confirm that the dimensions of heart are within the criteria for athletic heart syndrome [1] [2] [7]. The end-diastolic diameter of the left ventricle should not exceed 63 mm in men and 60 mm in women, Myocardial thickness of the left ventricle should not exceed 13 and 12 mm respectively, and the heart mass should not be over 7.5 g/kg for men and 7 g/kg in women [1] [8].

Early Repolarization
  • As mentioned previously, sinus bradycardia, AV blocks, extrasystoles, and early repolarization are hallmarks of athletic heart syndrome.[symptoma.com]
  • Differential diagnosis between early repolarization of athlete's heart and coved-type Brugada electrocardiogram. Am J Cardiol 2015;115:529-532.[ahcmedia.com]
  • repolarization pattern, n (%) 11 (34) 8 (25) NS Inverted/flattened T waves, n (%) 7 (22) 4 (12) NS Clinical Findings With Long-Term Detraining Over the long-term follow-up period, none of the 40 detrained athletes had adverse cardiovascular events or[circ.ahajournals.org]
  • This tracing shows early repolarization which occurs in athletes who develop diastolic overload of the ventricles.[rjmatthewsmd.com]


  • Managing treatment for Heart Disease is a highly personalized process.[familyheart.stanford.edu]
  • Treatment Treatment is not required for individuals diagnosed with athlete’s heart. No evidence has been found of any long-term danger from the changes regular exercise may cause to the heart.[sportsmedtoday.com]
  • الصفحة 24 - Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). ‏ الصفحة 134 - Sacks FM, Pfeffer MA, Moye LA et al.[books.google.com]
  • No treatment is necessary. Athlete’s heart is significant because it must be distinguished from serious cardiac disorders. Intensive, prolonged endurance and strength training causes many physiologic adaptations.[merckmanuals.com]


  • Prognosis The yearly rate for occurrence of SUD in people less than 35 years of age is less than 7 incidents per 100,000. Of all SUD cases, only about 8% are exercise related.[medical-dictionary.thefreedictionary.com]
  • Prognosis is generally poor, more because of the seriousness of predisposing disorders than the cardiac lesion. Treatment consists of anticoagulation with heparin (either intravenous unfractionated or subcutaneous low molecular weight).[merck.com]
  • Xian Li and Xianglin Cheng, Application of T-Wave Alternans in Evaluation of Prognosis in Patients with Intracerebral Hemorrhage, Yangtze Medicine, 01, 03, (127), (2017).[dx.doi.org]
  • Arrhythmogenic right ventricular cardiomyopathy: diagnosis, prognosis, and treatment. Heart. 2000 ; 83 :588–595. Crossref Medline Google Scholar 121. Maron BJ, Zipes DP.[circ.ahajournals.org]


  • View/Print Table TABLE 2 Likely Etiologies for Sudden Cardiac Death in Young Athletes Hypertrophic cardiomyopathy Coronary artery anomalies Atherosclerotic coronary artery disease Myocarditis Other etiologies (less common) Right ventricular dysplasia[aafp.org]
  • The etiological diagnosis is, however, essential. Indeed, giving medical clearance for sports participation to a patient with heart disease exposes that athlete to an elevated risk of an adverse cardiac event.[aspetar.com]
  • QT dispersion in patients with different etiologies of left ventricular hypertrophy:the significance of QT dispersion in enduranceathletes. Int J Cardiol 2002; 84: 153–9 PubMed CrossRef Google Scholar 48. Halle M, Huonker M, Hohnloser SH, et al.[dx.doi.org]


  • We really don’t know, but I think the observation, based on epidemiologic data, is valid,” he said. Proposed multifactorial mechanisms for the increased incidence of AF in aging endurance athletes hinge in part upon basic science studies.[mdedge.com]
  • "Significant evidence supports that athletes are "different" from nonathletes from the epidemiological, physiological, evaluation, and management perspectives, with significant heterogeneity among athlete subgroups.[athleticheartsf.com]
  • The use of screening tests, however, should be evaluated by epidemiologic criteria for determining effectiveness, not merely by media and/or public consensus.[aafp.org]
  • Everything here on out is epidemiology and public health concerns. There are three major studies of screening procedures serving as the predominant source of data in this argument.[jessefredeen.kinja.com]
  • Epidemiology and prognostic implications of syncope in young competing athletes. Eur Heart J. 2004 ; 25 :1749–1753. Crossref Medline Google Scholar 109. Basso C, Maron BJ, Corrado D, Thiene G.[circ.ahajournals.org]
Sex distribution
Age distribution


  • 1243 Percutaneous Coronary Intervention 1258 Percutaneous Cardiac Procedures 1273 Coronary Artery Bypass Surgery 1290 Approaches to the Patient with Prior Bypass Surgery 1306 Percutaneous Valve Dilatations 1316 Global Pandemic of Heart Failure 1330 Pathophysiology[books.google.com]
  • ATHLETE’S HEART DETERMINANTS The athlete’s heart pathophysiology is multifactorial 1. As with skeletal muscle, exercise modulates expression of the genome part which encodes for structural and metabolic proteins of the cardiovascular system.[aspetar.com]
  • Obesity cardiomyopathy: pathophysiology and evolution of the clinical syndrome. Am J Med Sci 2001; 321: 225–36 PubMed CrossRef Google Scholar 34. Opie LH, Commerford PJ, Gersh BJ, et al. Controversies in ventricular remodeling.[dx.doi.org]


  • It is not proven that ECG screening will prevent athlete sudden cardiac death. Pre-participation ECGs may increase false alarms for some athletes. Sports may not worsen all conditions, and we can’t prevent all deaths.[utswmedicine.org]
  • Prevention of cardiovascular events and death with pravastatin in patients with coronary heart disease and a broad range of initial cholesterol levels. ‏[books.google.com]
  • Preventing Sudden Death in Young Athletes The sudden death of a young athlete is a tragic event that has devastating effects on families and communities.[barnesjewish.org]
  • “To prevent one death in the U.S., where there’s a lower rate of inherited heart conditions that lead to sudden cardiac arrest, you’d have to stop almost 2,000 kids from playing sports,” he added.[today.com]
  • Lower resting heart rates in trained athletes prevents undue increase in heart rates with exercise. The opposite is seen a physically deconditioned individual, who has a rapid increase in heart rate even with low grades of exercise.[cardiophile.org]



  1. Scharhag J, Löllgen H, Kindermann W. Competitive Sports and the Heart: Benefit or Risk? Dtsch Arztebl Int. 2013;110(1-2):14-24.
  2. Khan AA, Safi L, Wood M. Cardiac Imaging In Athletes. Methodist Debakey Cardiovasc J. 2016;12(2):86-92.
  3. Riding NR, Salah O, Sharma S, et al. Do big athletes have big hearts? Impact of extreme anthropometry upon cardiac hypertrophy in professional male athletes. Br J Sports Med. 2012;46(1):i90-i97.
  4. Fagard R. Athlete’s heart. Heart. 2003;89(12):1455-1461.
  5. Caselli S, Maron MS, Urbano-Moral JA, Pandian NG, Maron BJ, Pelliccia A. Differentiating left ventricular hypertrophy in athletes from that in patients with hypertrophic cardiomyopathy. Am J Cardiol. 2014;114(9):1383–1389.
  6. Biffi A, Pelliccia A, Verdile L, et al. Long-term clinical significance of frequent and complex ventricular tachyarrhythmias in trained athletes. J Am Coll Cardiol. 2002;40:446–452.
  7. Afonso L, Kondur A, Simegn M, et al. Two-dimensional strain profiles in patients with physiological and pathological hypertrophy and preserved left ventricular systolic function: a comparative analyses. BMJ Open. 2012;2(4):e001390.
  8. Basavarajaiah S, Boraita A, Whyte G, et al. Ethnic differences in left ventricular remodeling in highly-trained athletes relevance to differentiating physiologic left ventricular hypertrophy from hypertrophic cardiomyopathy. J Am Coll Cardiol. 2008;51:2256–2262.

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Last updated: 2019-06-28 10:31