Call it heart attack risk: the abrupt, untimely departure of a chief executive officer—which, really, can leave any number of people experiencing chest pains.

Some CEOs might be whisked off to prison, such as Bernie Ebbers from WorldCom or Dennis Kozlowski from Tyco. Others might need to be dumped unceremoniously before a shareholder rebellion (think Robert Nardelli, formerly of Home Depot), or split town ahead of an indictment (think Kobi Alexander, formerly of Comverse Technologies and currently living in Namibia). A few, sadly, do die unexpectedly of heart attacks or other serious illness (Coca-Cola in 1994, McDonald’s in 2004).