Figure 1.

Comparison of survival rates (successful hospital discharge) in Seattle, USA, during the years when emergency responders made defibrillation attempts their first priority (1990–1993) versus subsequent years (1994–1996), when they provided 90 seconds of basic cardiopulmonary resuscitation before defibrillatory attempts for out-of-hospital cases of ventricular fibrillation. Survival rates and historical comparisons are stratified according to those patients receiving an emergency response within 4 min versus those with response intervals greater than 4 min. The response interval was measured from the time of dispatch of emergency vehicles until the time of arrival at the street address (not time of collapse to arrival at the patient's side). Adapted from Cobb and coworkers [8].