Automatic external defibrillators for prevention of out-of-hospital sudden death: effectiveness of the automatic external defibrillator.

Approaches to the prevention of sudden cardiac death (SCD) include strategies designed to attack the problem from the multiple perspectives of primary prevention of the underlying diseases, prophylactic treatment of high-risk individuals with identified diseases, and responses to cardiac arrest victims in the community. The latter strategy began with conventional fire department-based emergency rescue systems (emergency medical services [EMS]) that originated in the early 1970s. Although such systems were innovative and impressive at the time, they are limited by less-than-optimal response times that translate to low survival rates. Newer strategies, designed to respond faster, include a variety of methods, including ambulance- and police-based automatic external defibrillators (AEDs), deployment of AEDs in settings in which crowds accumulate and designated rescuers are available, and more general public access sites. The value of conventional EMS systems remains because of their ability to provide advanced life support as part of a dual-response system. These approaches, in conjunction with better primary and secondary prevention strategies, offer the hope of reducing the SCD burden.