Commotio Cordis occurs when there is a sudden blunt impact to the chest that causes sudden death. This is also known as an "R on T Phenomenon." This is a traumatic cause of arrest that produces Ventricular Fibrillation - typically, PEA or asystole is more expected in a traumatic arrest. Ventricular Fibrillation or pulseless Ventricular Tachycardia likely indicate a cardiac (or medical) cause of arrest.
Resuscitation in Commotio Cordis was once thought to be universally unsuccessful, now demonstrated to be successful in up to 35% of patients (AHA, 2012).
In an effort to decrease the incidence of Commotio Cordis, safety baseballs have been developed and encouraged. Safety baseballs have differing degrees of "hardness." At 40mph, softest safety baseballs trigged VF in only 11% of impacts, compared to 69% of impacts with standard baseballs.
For more information on Commotio Cordis, check out this AHA journal article: https://www.ahajournals.org/doi/full/10.1161/circep.111.962712