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The prevention of sudden death by athletes, defined as natural, unexpected, death within one hour of the onset of symptoms and subsequent cardiac arrest, remains a challenge. The prevalence of any single, associated condition is very low, probably less than 0.3% and the sensitivity and specificity of tests commonly used to screen leaves much to be desired. Wider definitions of sudden death are also in use but not usually applied to the athletic situation. The single most important predictor is exercise fainting or near fainting, which should require explanation and investigation. While most causes relate to congenital or acquired cardiovascular disease, an exception is commotio cordis, in which the heart is structurally normal but a potentially fatal loss of rhythm occurs because of the accident of timing of a blow to the chest. Survival is about 15% and time to CPR and defibrillation may determine this. ==Incidence== Sudden death occurs in approximately one in 200,000 athletes annually. The victim is usually male and, in the US, two-thirds occur in football and basketball. This reflects the popularity of these sports and the number of athletes involved in them and elsewhere in the world, soccer is most commonly associated. From statistics derived from NCAA data, one death per 25,000 collegiate athletes over a five-year period was attributable to medical causes. A series of observational studies have reported on death rates in athletes for causes other than trauma. Van Camp reported rates of approximately 7:1,000,000 and 1:1,000,000 for male and female high school and colleges students respectively, during organized athletic activity. Philips reported rates of 1:735,000 US Air Force recruits aged 17 to 28 during training. The sudden death rate amongst Rhode Island joggers was reported as 1:280,000 for those under 30 years of age, by Ragosta, and 1:7,260 for those 30–65 years according to Thompson. Finally, Maron reported rates of 1:50,000 race finishers in marathons, where the mean age was 37. To place in context, sudden cardiac death in the US (population 300 million), is estimated to occur 180,000 – 250,000 times per year. While the predominant cause is coronary artery and other vascular disease, about 20% of cases show no obvious structural cardiovascular abnormality and remain undiagnosed after autopsy. Interest in these 'autopsy-negative' deaths in the past ten years has centered around the 'ion channelopathies'. These channels are pores controlling the movement of sodium, potassium and calcium ions into cardiac cells, cumulatively responsible for creating and controlling the electrical signals which control the heart's rhythm. Abnormalities in this system are known to cause relatively rare genetic diseases such as 'Long QT syndrome', 'Brugada syndrome' and 'Catecholaminergic polymorphic ventricular tachycardia', all associated with sudden death. Consequently, more patients with autopsy-negative sudden cardiac death (no genetic abnormalities identified) may comprise a larger part of the 'channelopathies' than previously anticipated and it has been estimated that their incidence may be as high as 11/100,000, in a survey of unexpected sudden cardiac death in England, involving presumed healthy individuals aged 16–64 years. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sudden death (athletes)」の詳細全文を読む スポンサード リンク
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