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Re: Author's response

Dear Editor

I would like to thank Dr. Arno Müller for his thoughtful response to my recent editorial, and for raising several important points that I did not tackle in my brief consideration of the mass ECG screening of athletes.

Firstly, mass ECG screening is required by law in Italy [1], and is recommended by the European Society of Cardiology [2], but is not recommended by either the American Heart Association or the American College of Cardiology [3].  Nevertheless, Dr. Müller is correct in underlining that there is no rigid transatlantic divide on this issue.  Some groups in Europe accept that screening is inappropriate, and some supporters of mass screening can undoubtedly be found in North America.

Secondly, a family history of sudden premature death undoubtedly gives some indication of an increased risk of sudden death in a young athlete.  But unfortunately, a family history of premature death is by no means universal in patients with hypertrophic cardiomyopathy.  Is genetic technology helpful in identifying a sub-group of vulnerable individuals, thus allowing cost-effective detailed investigation with a low burden of false positive test results?  Certainly, a variety of genetic mutations have been associated with hypertrophic cardiomyopathy, including abnormalities that affect cardiac troponins T and I, the beta- myosin heavy chain, alpha tropomyosin, alpha-actin and myosin-binding protein C [4-10].  At only one of several possible sites of mutation, the chromosomal locus 14ql, as many as 36 possible abnormalities of the β-MHC gene have been implicated [5]; some of these mutations are associated with a dramatic shortening of life span, but with others, the life span is virtually normal.  The phenotypic penetrance of the abnormal genotype is often low, and sometimes there is an interaction with environmental factors; if myocardial hypertrophy develops at all, it may not be seen until middle age.  Further, about a half of the cases of hypertrophic cardiomyopathy apparently have no genetic basis [5]. The rarity and heterogeneity of the relevant genetic abnormalities, and the variability of their penetrance are important obstacles. Genetic screening is also tedious, time-consuming and expensive.  Thus, at present this approach cannot be recommended as a method of triage prior to more detailed electrocardiographic and echocardiographic screening.

Does a sinister fear of legal action cause some physicians to oppose universal ECG screening?  One would certainly hope not.  In general, if there is fear of a malpractice suit in North America, it acts in the opposite sense to what Dr. Müller suggests.  There is a regrettable tendency to perform tests that are unnecessary or have little diagnostic value, because the physician fears criticism for not undertaking a thorough enough screening protocol. B.J. Maron argues that a successful action for malpractice in relation to pre-participation screening would require evidence of negligence, including deviation from accepted medical practice, and a failure to use established diagnostic criteria that would have disclosed the risk of sudden death during exercise [11]. At least in North America, neither of these conditions is satisfied if a physician has advised against ECG screening.

Does an athlete have the right to insist on ECG screening?  Given that little useful information is likely to result, this should not be permitted if the costs of testing are to be met from the public purse.  However, if the competitor or the parents are prepared to assume this expense, there can be little objection, provided that the fallibility of the test has been explained clearly to them.  The only potential harm to the athlete is a false positive test result, and thus an unnecessary subsequent restriction of physical activity.

A related question is whether athletes want to know about possible contraindications to participation in their chosen sport.  In general, both the individual and society accept that we are unlikely to achieve zero risk in competitive sports.  For activities such as mountain climbing and snow-boarding, risk is an inherent part of the experience for the participant. Equally, in traditional sports such as North American football, most team members recognize and accept the current risks of major trauma and fatalities, and few would wish to abandon competition because they cannot be assured of a 100 per cent safety record. 

References

1. Corrado D, Basso C, Pavei A, et al. Trends in sudden  cardiovascular death in young competitive athletes after implementation of a preparticipation screening program. JAMA 2006;296:1593–601.

2. 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;26:516–24.

3. 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;115:1643–55.

4. Geisterfer-Lowrance AAT, Kass S,Tanigawa G et al. A molecular basis for familial hypertrophic cardiomyopathy: a β-myosin heavy chain gene mutation. Cell 1990; 62: 999-1006.

5. Marian AJ, Roberts R. Recent advances in the molecular genetics of hypertrophic cardiomyopathy. Circulation 1995; 92:1336-47.

6. Schwarz K, Carrier L, Guicheney P et al. Molecular basis of familial cardiomyopathies, Circulation 1995; 91: 532-540.

7. Spirito P, Seidman CE, McKenna WJ et al. The management of hypertrophic cardiomyopathy. N Engl J med 1997; 336: 775-785.

8. Thierfelder L, Watkins H, MacRae C et al. α-tropomyosin and cardiac troponin T mutations cause familial hypertrophic cardiomyopathy: a disease of the sarcomere. Cell 1994; 77: 701-712.

9. Watkins H, Conner D, Thierfelder L et al. Mutations in the cardiac myosin binding protein-C gene on chromosome 11 cause familial hypertrophic cardiomyopathy. Nature Genetics 1995; 11: 434-437.

10. Daw EW, Chen SN, Czernuszewicz G. et al. Genome-wide mapping of modifier chromosomal loci for human hypertrophic cardiomyopathy. Human Mol Genet 2007; 16:2463-71, 2007.

11. Maron BJ. Considerations for preparticipation cardiovascular screening in young competitive athletes. In: Endurance in Sport, 2nd ed. Editors: R.J. Shephard, P-O Ã…strand. Oxford, UK: Blackwell Scientific, 2000; pp. 667-681.

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Re: What about Ethics and Genetics?

The Editorial by Shephard addresses the potential problems involved in a mass ECG screening for athletes. He explains that on the one hand Italian (sport)cardiologists are in favor of a (mandatory) mass screening program, while on the other hand US physicians seem to have good reasons for opposing this Italian model.

Although Shepard’s review is agreeable to the current situation, he neglects some important issues. I will just sketch two of them:

• What about genetic testing? Could genetic testing be a helpful tool for diagnosis/differential diagnosis? Could a cascade screening, i.e. testing of family members of a person at risk help to reduce the numbers of sudden death in athletes and at the same time reduce the costs?

• What about further legal and ethical aspects? Is it only a factual disagreement? Or is there maybe a moral divergence behind the opposing view in the US? Or is the opposition to a mass screening the result of US physicians fears of lawsuits? Do the athletes have a voice in this process? What about the athletes right to know – their right not to know about their medical condition?

Besides these two important aspects of pre participation screening in general and the question if the ECG should be part of it, I finally wanted to mention that the often simplified picture on Europe suggests that there is this dichotomy of views that Shephard offers us (USA vs. Europe). But the range of opinions on this issue in Europe is far more heterogeneous than this. For example many Scandinavian countries are not convinced by the Italian model so far and therefore do not support the implementation of a mandatory mass ECG screening for athletes.