Preventing sudden cardiac death in athletes
BMJ 2016; 353 doi: https://doi.org/10.1136/bmj.i1270 (Published 20 April 2016) Cite this as: BMJ 2016;353:i1270
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Surprisingly, in their editorial, Preventing sudden cardiac death in athletes, Semsarian and Ingles did not mention the importance of magnesium and omega-3 fatty acids.
The link between magnesium deficiency and sudden cardiac death has been suggested by a substantial number of published studies over the past few decades. Data come from epidemiologic, autopsy, clinical, and animal studies. They suggest that: (1) Sudden death is common in areas where community water supplies are Mg-deficient. (2) Myocardial Mg content is low in people who die of sudden death. (3) Cardiac arrhythmias and coronary artery vasospasm can be caused by Mg deficiency and (4) Intravenous Mg reduces the risk of arrhythmia and death immediately after acute myocardial infarction (i). Further, magnesium is lost in sweat during strenuous exertion, exacerbating any pre-existing magnesium insufficiency or deficiency.
Omega-3 deficiency may also play a role; a considerable body of evidence has shown that low omega-3 fat intake significantly increases the risk and severity of cardiac arrhythmias, the main cause of sudden cardiac death.
A recent study determined the Omega-3 Index in 106 consecutive German national elite winter endurance athletes presenting for pre-participation screening, using a well-established analytical procedure (HS-Omega-3 Index) - only one athlete had a value within the target range; all others had values <8%. The authors concluded that the deficiency of EPA and DHA in these athletes deficiency presents a potential option for prevention of cardiovascular events such as sudden cardiac death (ii).
Screening athletes for magnesium and omega-3 deficiency should be considered, along with appropriate supplementation to reduce their risk of sudden death.
(i) Magnesium deficiency and sudden death. Eisenberg MJ. Am Heart J. 1992 Aug;124(2):544-9
(ii) Low Omega-3 Index in 106 German elite winter endurance athletes: a pilot study. von Schacky C1, Kemper M, Haslbauer R, Halle M. Int J Sport Nutr Exerc Metab. 2014 Oct;24(5):559-64. doi: 10.1123/ijsnem.2014-0041. Epub 2014 Sep 8
Competing interests: No competing interests
As a GP and sports coach, I would certainly agree that widespread teaching of BLS and access to AEDs are likely to be be more important than screening. However, I do have two questions. Firstly, is there any evidence for echocardiography as a screening tool? Secondly, is there any research on the role of acute infections in precipitating sudden cardiac death?
Competing interests: No competing interests
Re: Preventing sudden cardiac death in athletes (response to Dr Jarrett)
Dear Dr Jarrett
Thank you for your questions. Echocardiography is usually reserved for athletes in which there is either a suspicious personal or family history, or following an abnormal ECG (e.g. LVH). There is no definitive evidence of echocardiography as a primary screening tool in athletes. In terms of infection, direct viral infection of the heart, leading to myocarditis, is a recognised cause of sudden cardiac death in athletes. Systemic infections leading to fever can trigger arrhythmias, e.g. in Brugada syndrome.
Helpful review: http://www.bmj.com/content/350/bmj.h1218
Competing interests: No competing interests