What is it? Commotio Cordis is a "Cardiac Concussion" or a disturbance of the heart. It is a non-penetrating, precordial blow to the chest that causes cardiac arrest and tachycardia/ fibrillation. This is unassociated with any structural damage to the heart, ribs, or sternum.
Russell, Trixie; Weir, Jasmine; Castleberry, Randa; and Mahlock, Kris, "Commotio Cordis" (2013). Student Research. 1.