Commotio Cordis

Commotio cordis (Latin, "agitation of the heart") is an often lethal disruption of heart rhythm that occurs as a result of a blow to the area directly over the heart (the precordial region), at a critical time during the cycle of a heart beat. It is a form of ventricular fibrillation, not mechanical damage to the heart muscle or surrounding organs, and not the result of heart disease. The fatality rate is about 65%. It can sometimes, but not always, be reversed by defibrillation.

Commotio cordis occurs mostly in boys and young men (average age 15), usually during sports, most often baseball, often despite a chest protector. It is most often caused by a projectile, but can also be caused by the blow of an elbow or other body part. Being less developed, the thorax of an adolescent is likely more prone to this injury given the circumstances.

The phenomenon was confirmed experimentally in the 1930s, with research in anaesthetized rabbits, cats and dogs.