Background: The potential impact of efforts to improve the chain of survival for out-of-hospital sudden cardiac arrest (SCA) is unclear in part because estimates of the incidence of treatable cases of SCA are uncertain. The aim of the investigation was to determine a representative national incidence of emergency medical services (EMS)-treated all-rhythm and ventricular fibrillation (VF) SCA as well as survival.
Methods: We used Medline to identify peer-reviewed articles published between 1 January 1980 and 31 March 2003 that reported a US community's EMS SCA experience. Inclusion criteria required the study to include at least 25 cases, report the total number of all-rhythm and/or ventricular fibrillation arrests, and provide information about population size and study duration. Incidence was computed by dividing the total number of SCA events by the product of the community's population and the study duration.
Results: Reports from 35 communities met the inclusion criteria. A total of 35,801 all-rhythm EMS-treated cardiac arrests occurred during 62.11 million person-years of observation resulting in an overall incidence of 54.99 per 100,000 person-years. The incidence of ventricular fibrillation-rhythm SCA was 21.32 per 100,000 person-years. Sensitivity analyses generally produced similar results. Applying these results to the US population, 155,000 persons would experience EMS-treated all-rhythm SCA and 60,000 persons would experience EMS-treated ventricular fibrillation-rhythm SCA annually in the US. Survival was 8.4% for all-rhythm and 17.7% for ventricular fibrillation SCA.
Conclusion: The results provide a framework to assess opportunities and limitations of EMS care with regard to the public health burden of SCA.