Commotio Cordis Leads to Sudden Cardiac Arrest

Commotio Cordis is the medical term for a rare disruption of the heart's electrical system resulting from a blunt impact to the chest that leads to sudden cardiac arrest.

Commotio cordis:

• Has been documented in over 128 cases in the four years since the formation of the United States Commotio Cordis Registry in Minneapolis, Minnesota in 1998, although the true number of deaths is unknown because of underreporting and misclassification¹.

• The commotio cordis sudden-death rate is highest in lacrosse (.63 deaths per 100,000 person-years), hockey (.53 deaths per 100,000 person-years) and baseball (.24 deaths per 100,000 person-years), rates significantly higher than in other sports.²

• Is largely the result not of the force of the blow but from an incredibly untimely blow contacting the chest directly over the heart at just the wrong time -- the precise millisecond between heart contractions that throws the heart into a lethal abnormal heart rhythm called "ventricular fibrillation" or VF, which causes a useless quivering of the heart that results in a complete cessation of circulation instantly depriving the brain and other vital organs without circulation and oxygen. The blows usually causes no identifiable structural injury to the ribs, sternum or to the heart itself.

• Occurs most often in healthy young athletes, who are especially at risk because the pliability of their chest walls. In one study of 55 cases of sudden cardiac arrest, 90% were 16 years of age or younger, 25 were playing in organized athletic events such as baseball, softball, and ice hockey. The remaining 30 children were playing informal sports at home, school or on the playground. None of the children showed evidence of any heart defect or diseases.

• Cannot be completely eliminated through the use of protective equipment. Commercially available chest protectors have not been shown to prevent against commotio cordis for athletes playing baseball, lacrosse, hockey and softball.³ Studies have shown that the use of softer, lighter baseballs may reduce the risk of commotio cordis. Softer, heavier (so-called Reduction In Force or "RIF") baseballs may actually increase the risk of commotio cordis.

• Has a survival rate that declines by approximately 7 to 10% for every additional minute that passes without defibrillation. After 12 minutes, the time Emergency Medical Service (EMS) paramedics typically arrive, it is usually too late (the national survival rate from sudden cardiac arrest (SCA) is a dismal 5%. In some cities it is as low as 1 to 2%.

• Requires community-based programs using Automated External Defibrillators (AEDs) if the survival rate is to be increased. When defibrillation is delivered in one minute, the reported survival rates can be as high as 90%. For defibrillation within 5 minutes, the survival rate can be as high as 50%. Of ten athletes who experienced commotio cordis from being struck by a lacrosse ball (8) or stick (2), timely defibrillation was performed on 7, with 4 surviving.¹

To prevent deaths from commotio cordis it is necessary to train coaches, bystanders and other sports personnel in the recognition of this event and timely response. Basic life support training and access to AEDs are crucial to achieving this goal.

1. Maron, B.J., et. al., "Sudden Death in young competitive athletes: analysis of 1,866 deaths in the U.S 1980-2006. Circulation 2009; 119(8): 1085-1092.
2. Maron, B.J. et. al., "Commotio Cordis and the Epidemilogy of Sudden Death in Competitive Lacrosse," Pediatrics 124 (3); 976-981, September 2009.
3. Weinstock, J. et. al., "Failure of commercially available chest wall protectors to prevent sudden cardiac death induced by chest wall blows in an experimental model of commotio cordis" Pediatrics, 2006; 117(4).