EDITORIAL COMMENT
Differences in Cardiac Remodeling Associated With RaceImplications for Pre-Participation Screening and the Unfavorable Situation of Black Athletes*
Antonio Pelliccia, MD*
Institute of Sports Medicine and Science, Italian National Olympic Committee, Rome, Italy.
* Reprint requests and correspondence: Dr. Antonio Pelliccia, Institute of Sports Medicine and Science, Largo Piero Gabrielli, 1, 00197 Rome, Italy. (Email: ant.pelliccia{at}libero.it).
The unexpected, tragic, and highly publicized sudden deaths of top-level athletes reported by the media periodically inflate the debate regarding the most appropriate strategy for identifying individuals at risk and preventing these catastrophes (1–3). Indeed, there is a growing perception in the lay public and medical community that the prevalence of athletic field deaths is larger than previously believed and, although not epidemic, there are innumerable events terminating the lives of young athletes that pass uncovered by media.
Pre-participation cardiovascular screening, routinely including 12-lead electrocardiography (ECG), has been in practice in Italy in the last 25 years (4), and has been shown to reduce mortality in a large population of young competitive athletes, owing to timely identification (largely with ECG) of individuals with clinically silent cardiomyopathies and their subsequent disqualification from competitive sport (5). The inclusion of ECG into pre-participation screening programs has been supported by the European Society of Cardiology and the Medical Commission of the International Olympic Committee (6,7). Recently, the statement that ECG should be included in the pre-participation screening of collegiate and high school athletes in the U.S. has been endorsed in a highly publicized scientific debate (8).
However, the implementation of the 12-lead ECG into pre-participation screening is a still-debated clinical issue and raises justified concern, owing to the expected large proportion of abnormal patterns in young trained individuals (9), which would require additional diagnostic testing to confirm (or exclude) the presence of underlying cardiovascular disease (10,11).
In this perspective, the paper by Magalski et al. (12) in this issue of the Journal, deserves particular interest. The authors (12) have investigated the potential impact of race on ECG changes in young trained athletes. In a large cohort of 1,959 collegiate football players (of whom 67% were black), the authors found a substantially larger proportion of abnormal ECGs in black compared with white athletes (30% vs. 13%; p < 0.001). In this regard, it is worth noting that the prevalence of ECG abnormalities in white U.S. athletes is similar to that found in white European athletes (i.e., 11.8% in a large cohort of Italian young athletes) (13) and confirms that only a relatively small proportion of young white subjects show ECG changes that raise clinical concern for underlying pathologic conditions.
Indeed, Magalski et al. (12) described that the most abnormal patterns, including markedly increased R/S wave voltages, diffuse T-wave inversion, and deep Q waves (defined as distinctly abnormal ECGs), suggesting the presence of cardiac disease, were found in 5.8% of blacks versus only 1.8% of whites (p < 0.005). These striking patterns were >10 times more common in blacks than in whites and explained most of the differences associated with race (12). In conclusion, black race was the only independent predictor for all of the abnormal ECGs (relative risk [RR] 2.03) and, specifically, for the distinctly abnormal ECGs (RR 2.59), after adjustment for all other variables.
In addition, the presence of abnormal ECGs was somehow related to football player position, with wide receivers, defensive backs, and running backs showing >2-fold more abnormalities compared with other players. The relationship of ECG pattern to type of training and endurance capacity is consistent with the results of a previous investigation in a large cohort of Italian competitive athletes and suggests that extent of physiologic cardiac remodeling may be, at least in part, responsible for the alterations in the ECG (9).
Unfortunately, the authors were not able to collect ECGs from all individuals presenting with abnormal ECGs, and, therefore, the proportion of false-positive results in black versus white athletes was not defined. However, in all athletes in whom echocardiography was performed no cardiac disease was found, raising suspicion that a majority of abnormal ECGs might represent false-positive results.
Also in this issue of the Journal, Basavarajaiah et al. (14) conducted a comparative ECG study of cardiac dimensions in black versus white young athletes. Black athletes showed greater LV wall thickness and mass but similar cavity size compared with white athletes matched for age, body size, and level of blood pressure. In addition, a larger proportion of black athletes (18% vs. 4%) showed LV wall thickness increased above normal values (i.e., >12 mm), including an important subset of 3% showing substantial wall thickening ( 15 mm), suggesting the presence of hypertrophic cardiomyopathy (HCM).
As a corollary finding, Basavarajaiah et al. (14) described that ECG changes suggestive of LV hypertrophy (Sokolow-Lyon voltage criteria) were much more common in black athletes with echocardiographic evidence of LV hypertrophy (i.e., 68% vs. 40% of white athletes; p < 0.001). Moreover, certain ECG abnormalities that are consistently found in HCM, such as deep T-wave inversion in precordial leads, occurred in a substantial minority of black (12%) but in no white athletes (14).
A new valuable insight provided by the Basavarajaiah et al. (14) investigation was the different predisposition for LV hypertrophy with respect to the ancestral origin of black athletes (i.e., the Caribbean, West Africa, or East Africa). The LV hypertrophy was predominately seen in individuals originating from the Caribbean or West Africa (20%) and was unusual in individuals coming from East Africa (7%).
Therefore, it seems that ethnicity (through a combination of genetic, endocrine, and other still unknown mechanisms) may be responsible in black athletes (and mostly in those from West Africa or Caribbean) for a disproportionate cardiac remodeling, characterized by a greater LV wall thickening (but equivalent cavity size), than in white athletes. Consistently, cardiac remodeling is associated with a larger prevalence of ECG alterations suggestive of LV hypertrophy in West African or Afro-Caribbean compared with white athletes.
The novel data provided by these 2 studies are of particular clinical interest for their implications in the cardiovascular screening of young competitive athletes. It appears that young black individuals are in a particularly unfavorable situation when exposed to pre-participation screening programs. Black athletes have a disproportionately higher probability of showing abnormal ECG patterns compared with their white teammates and, specifically, of presenting those alterations that unavoidably raise question of underlying HCM. Consequently, echocardiography or other imaging testing (i.e., cardiac magnetic resonance) will be needed to solve the ambiguity of abnormal ECG patterns in a larger proportion of black compared with white individuals, multiplying the occurrence of false-positive results and thus the probability for black athletes to be disqualified from competitive sports.
Therefore, the Magalski et al. (12) and Basavarajaiah et al. (14) studies have relevance to the contemporary scientific debate regarding the feasibility and limitation of pre-participation screening programs in young athletes (8,10). The data suggest the impracticality of cardiovascular screening programs in large populations of black athletes, not only for the expected large proportion of ECG abnormalities and the disproportionate request for imaging and other testing in selected cases, but also for the limited access to medical services of a sizeable proportion of the black population, which includes several millions of uninsured young individuals.
However, considerating that sudden cardiac deaths disproportionately affect young black athletes (>40% of all athletic field deaths) (2), we believe that scientific associations should pursue all efforts to reduce the burden of these adverse events by supporting the most cost-efficient strategy to timely identify all young individuals at risk. In this perspective, the studies by Magalski et al. (12) and Basavarajaiah et al. (14) are of particular clinical value in adjusting our biased knowledge of normality (derived from previous investigations made in white subjects) by introducing the novelty of race-related appropriate standards for interpretation of ECG pattern and physiologic cardiac remodeling in athletes, therefore diminishing the risk for black athletes to be deprived of the many opportunities and benefits (including economic) derived from an athletic lifestyle.
In the near future, efforts should be made to better understand the mechanisms and limits of different cardiac response to athletic conditioning in athletes, and new standards should be defined with consideration of ethnicity in addition to age, gender, and sport. These investigations are particularly needed in countries with heterogeneous populations to offer equal opportunities to the different segments of those societies. In this perspective, implementation of large-scale screening programs with 12-lead ECG in athlete populations of different ethnic origins represent the way to increase our knowledge, with ensuing applications in the customary clinical practice (15).
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Footnotes
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* Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology. 
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References
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1. Maron BJ. Sudden death in young athletes: lessons from the Hank Gathers affair N Engl J Med 1993;329:55-57.[Free Full Text]2. Maron BJ, Shirani J, Poliac LC. Sudden death in young competitive athletes. Clinical, demographic, and pathological profiles. JAMA 1996;276:199-204.[Abstract/Free Full Text] 3. Maron BJ. Sudden death in young athletes N Engl J Med 2003;349:1064-1075.[Free Full Text] 4. Pelliccia A, Maron BJ. Preparticipation cardiovascular evaluation of the competitive athlete: perspectives from the 30-year Italian experience Am J Cardiol 1995;75:827-829.[CrossRef][Web of Science][Medline] 5. Corrado D, Basso C, Pavei A, Michieli P, Schiavon M, Thiene G. Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program JAMA 2006;296:1593-1601.[Abstract/Free Full Text] 6. Corrado D, Pelliccia A, Bjornstad HH, et al. Cardiovascular pre-participation screening of young competitive athletes for prevention of sudden death: proposal for a common European protocol. Consensus statement of the Study Group of Sport Cardiology of the Working Group of Cardiac Rehabilitation and Exercise Physiology and the Working Group of Myocardial and Pericardial Diseases of the European Society of Cardiology. Eur Heart J 2005;26:516-524.[Abstract/Free Full Text] 7. Bille K, Schamasch P, Figoeiras D, et al. Sudden cardiac death in athletes: the Lausanne Recommendations Eur J Cardiovasc Prev Rehabil 2006;13:859-875.[CrossRef][Web of Science][Medline] 8. Myerburg RJ, Vetter VL. Electrocardiograms should be included in preparticipation screening of athletes Circulation 2007;116:2616-2626.[Free Full Text] 9. Pelliccia A, Maron BJ, Culasso F, et al. Clinical significance of abnormal electrocardiographic patterns in trained athletes Circulation 2000;102:278-284.[Abstract/Free Full Text] 10. Maron BJ. How should we screen competitive athletes for cardiovascular disease? Eur Heart J 2005;26:428-430.[Free Full Text] 11. Maron BJ, Thompson PD, Ackerman MJ, et al. Recommendations and considerations related to preparticipation screening for cardiovascular abnormalities in competitive athletes: 2007 update: a scientific statement from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism: endorsed by the American College of Cardiology Foundation Circulation 2007;115:1643-1655.[Free Full Text] 12. Magalski A, Maron BJ, Main ML, et al. Relation of race to electrocardiographic patterns in elite American football players J Am Coll Cardiol 2008;51:2250-2255.[Abstract/Free Full Text] 13. Pelliccia A, Culasso F, Di Paolo F, et al. Prevalence of abnormal electrocardiograms in a large, unselected population undergoing preparticipation cardiovascular screening Eur Heart J 2007;28:2006-2010.[Abstract/Free Full Text] 14. 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.[Abstract/Free Full Text] 15. Pelliccia A. The preparticipation cardiovascular screening of competitive athletes: is it time to change the customary clinical practice? Eur Heart J 2007;28:2703-2705.[Abstract/Free Full Text]
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