Sudden cardiac death of athletes

It remains a difficult medical challenge to prevent the sudden cardiac death of athletes, typically defined as natural, unexpected death from

The sudden cardiac deaths of 387 young American athletes (under age 35) were analyzed in a 2003 medical review:[3]

While most causes of sudden cardiac death relate to

Age 35 serves as an approximate borderline for the likely cause of sudden cardiac death. Before age 35, congenital abnormalities of the heart and blood vessels predominate. These are usually asymptomatic prior to the fatal event, although not invariably so.[6] Congenital cardiovascular deaths are reported to occur disproportionately in African-American athletes.^[7]

After age 35, acquired coronary artery disease predominates (80%),^[6] and this is true regardless of the athlete's former level of fitness.^{[citation needed]}

Various

Cardiomyopathies are generally inherited as

Since HCM, as an example, is typically an autosomal dominant trait, each child of an HCM parent has a 50% chance of inheriting the mutation. In individuals without a family history, the most common cause of the disease is a "de novo" mutation of the gene that produces the β-myosin heavy chain.^[citation needed]

Channelopathies

Sudden cardiac death can usually be attributed to cardiovascular disease or commotio cordis, but about 20% of cases show no obvious cause and remain undiagnosed after autopsy. Interest in these "autopsy-negative" deaths has centered around the "ion channelopathies". These electrolyte channels are pores regulating the movement of sodium, potassium and calcium ions into cardiac cells, collectively responsible for creating and controlling the electrical signals that govern the heart's rhythm. Abnormalities in this system occur in relatively rare genetic diseases such as Long QT syndrome, Brugada syndrome, and Catecholaminergic polymorphic ventricular tachycardia, all associated with sudden death. Consequently, autopsy-negative sudden cardiac deaths (no physical abnormalities identified) may comprise a larger part of the channelopathies than previously anticipated.^[10][11]

Heritable connective tissue diseases

Heritable connective tissue diseases are rare, each disorder estimated at one to ten per 100,000, of which

Recruiting practices aimed at attracting athletes who are unusually tall or who have an unusually wide arm span (characteristics of Marfan syndrome) can increase the prevalence of the syndrome within sports such as basketball and volleyball.[15]

DNA testing

After a disease-causing mutation has been identified in an index case (which is not always accomplished conclusively), the main task is genetic identification of carriers within a pedigree, a sequential process known as "cascade testing". Family members with the same mutation may show different severities of disease, a phenomenon known as "variable penetrance". As a result, some may remain asymptomatic, with little lifelong evidence of disease. Nevertheless, their children remain at risk of inheriting the disorder and potentially being more severely affected.^[16]

Screening

Screening athletes for cardiac disease can be problematic because of low prevalence and inconclusive performance of various tests that have been used. Nevertheless, sudden death among seemingly healthy individuals attracts much public and legislator attention because of its visible and tragic nature.^[17]

As an example, the

In the United States approximately 8 to 10 deaths per year can be attributed to sudden cardiac death in NCAA with overall rate of 1 per 43,000.^[21][22]

Notable cases

These athletes, with notable careers, experienced sudden cardiac death by age 40.

See also

• Cardiac Risk in the Young (UK charity)
• Lists of sportspeople who died during their careers

References