commotio cordis
noun
com·mo·tio cor·dis
| \ kə-ˈmō-shē-ō-ˈkȯrd-əs
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Medical Definition of commotio cordis
: concussion of the heart that is caused by a blow to the chest over the region of the heart by a blunt object (as a baseball, hockey puck, or fist) which does not penetrate the body and that usually results in ventricular fibrillation leading to sudden cardiac death if treatment by defibrillation is not immediately given