Few diseases have such disparate clinical outcomes in the absence of definitive treatment as sudden cardiac death. Many studies have shown excellent outcomes in patients resuscitated after sudden cardiac death who receive early defibrillation, so it is logical for doctors to seek to extend this powerful treatment to other populations at high risk. Unfortunately, the trials that have sought to protect individual patients with automated external defibrillators have been overwhelmingly unsuccessful. In light of the fortuitous convergence of circumstances that leads to a successfully resuscitated out of hospital cardiac arrest, the task of broad application of this treatment seems indeed daunting.

First, defibrillation works only for patients presenting with ventricular tachyarrhythmia. The current incidence of out of hospital cardiac arrest in the United States is 0.55 per 1000 people—about 160 000 events a year.1 Of these arrests, only 20-38% will have ventricular tachycardia or ventricular fibrillation at presentation; thus most …