Recovery from nontraumatic cardiac arrest depends on the presence of all the elements in the chain of survival. "Early defibrillation" is critical because ventricular fibrillation is the most common initial dysrhythmia of sudden cardiac arrest. Defibrillation is the only treatment, and survival from ventricular fibrillation is determined by time. Out-of-hospital studies have demonstrated that defibrillation provided by first responders improves survival. Technologic advances have simplified defibrillation delivery through the development of automated external defibrillators (AEDs). Early defibrillation programs with AEDs are quickly becoming a standard of care for emergency medical service systems throughout the United States. Improvement in in-hospital survival rates from cardiac arrest is not as evident as in the emergency medical service community. Medical centers need to assess response times to cardiac arrest and implement AED programs. All the nurses should learn to use an AED as part of basic life support training.