BACKGROUND: Sudden death from cardiac arrest in a young person may occur during 
sports play after a blunt blow to the chest in the absence of structural 
cardiovascular disease or traumatic injury (cardiac concussion or commotio 
cordis). We studied the clinical features of this apparently uncommon but 
important phenomenon.
METHODS: We identified cases from the registries of relevant agencies and 
organizations, as well as newsmedia accounts, and developed a clinical profile 
of 25 children and young adults, 3 to 19 years of age.
RESULTS: Each victim collapsed with cardiac arrest immediately after an 
unexpected blow to the chest, which was usually inflicted by a projectile (such 
as a baseball or hockey puck). Incidents took place during organized competitive 
sports in 16 cases and in recreational settings at home, at school, or on the 
playground in 9. In each instance, the impact to the chest was not judged to be 
extraordinary for the sport involved and did not appear to have sufficient force 
to cause death. Twelve victims collapsed virtually instantaneously on impact, 
whereas 13 remained conscious and physically active for a brief time before 
cardiac arrest. Cardiopulmonary resuscitation was administered within about 
three minutes to 19 victims, but normal cardiac rhythm could be restored in only 
2 (both incurred irreversible brain damage and died shortly thereafter). Seven 
victims (28 percent) were wearing some form of protective chest padding.
CONCLUSIONS: We speculate that most sudden deaths related to impact to the chest 
(not associated with traumatic injury) are due to ventricular dysrhythmia 
induced by an abrupt, blunt precordial blow, presumably delivered at an 
electrically vulnerable phase of ventricular excitability. This profile of blunt 
chest impact leading to cardiac arrest adds to our understanding of the range of 
causes of sudden death on the athletic field and may help in the development of 
preventive measures.