Commotio Cordis Resulting from Sibling Rivalry.

A 17-year-old girl with no significant medical, surgical, or family history presented to the emergency department following an episode of sudden cardiac arrest after being punched in the chest by her brother. Bystander CPR was immediately initiated, and she was found to be in ventricular fibrillation by emergency services. The patient had return of spontaneous circulation after one defibrillation event. No other significant injuries were found, and she eventually experienced a complete neurologic recovery and was discharged with no other identified cause for her arrest. The objective of this clinical case report is to highlight this unusual and rare injury to increase awareness and avoid incorrect diagnosis.