Since its inception at the first modern Olympic Games in 1896, the marathon has gained popularity with participation rising from an estimated 143,000 US marathon finishers in 1980 to a record high of 507,000 during 2010 (11,17). Because regular exercise promotes health (2), the concept of death during a marathon is unsettling.
The vast majority of marathon deaths are caused by sudden cardiac arrest (SCA), defined as the sudden termination of cardiac activity with hemodynamic failure (3). Most victims of exercise-related SCA have no premonitory symptoms (18). Autopsy reports have shown that 65%–70% of all adult sudden cardiac deaths (SCDs) are attributable to CAD, 10% are due to other structural heart diseases (e.g., hypertrophic cardiomyopathy, congenital coronary anomalies), 5%–10% are due to primary cardiac conduction disorders such as prolonged QT and ion channel disorders, and the remainder are due to noncardiac etiologies (4–7,19).