As per the study, researchers have reviewed 13,769 cases of SCA occurring outside hospitals in multiple sites in the US and Canada. An AED was used before arrival of emergency medical services (EMS) personnel in 2.1% of cases. Survival in the overall group was 7%, compared to 24% when an AED was applied before EMS arrival, and 38% when an AED shock was delivered before EMS arrival.

Use of an AED before EMS arrival increased the odds of survival by 80%. When study results were extrapolated to the entire population of the US and Canada, researchers found that 470 people are saved each year due to bystander use of AEDs.

Myron Weisfeldt, principal investigator and director of Department of Medicine at Johns Hopkins Medical Institutions, said: “This is the first time a broad population was studied in this country. The study shows in a dramatic way that the use of AEDs by bystanders is a very potent indicator of survival.”

Mary Newman, president of the Sudden Cardiac Arrest Foundation, said: “The study is the landmark research we have been waiting for. It confirms the need for widespread deployment of AEDs, and the need for the public to become familiar with their use.”