The Chain of Survival is a metaphor used to describe the sequence of therapeutic interventions for cardiac arrest is the Chain of Survival. Successful treatment of cardiac arrest and particularly ventricular fibrillation is associated with an EMS systems ability to deliver care quickly. The chain of survival, with its four pre-hospitals links of early access, early CPR, early defibrillation, early advanced care, illustrates the most critical elements of addressing sudden cardiac arrest.

Every EMS system already incorporates some if not all of these system factors at least to some degree – but even these factors, although necessary, are not sufficient. After all, a sports team can have great individual players but still lose every game.