2. Yes, this is a thing. From the American Heart Association:
Commotio cordis is a phenomenon in which a sudden blunt impact to the chest causes sudden death in the absence of cardiac damage. This condition was first described in the middle of the 18th century in the context of chest trauma among workers …commotio cordis events have primarily occurred in sports… Baseball is the most common sport in which commotio occurs. Nearly all commotio events are caused by direct baseball strikes to the left chest wall over the cardiac silhouette. Pitchers, catchers, and batters have the highest incidence of commotio cordis.