Study finds training bystanders and responders does not boost survival after sudden cardiac arrest

Sudden cardiac arrest kills about 350,000 people in the United States each year, and only one in ten victims survive. Survival depends heavily on rapid CPR and defibrillation by nearby bystanders or emergency crews, with chances dropping roughly 10% for each minute without intervention.

A randomized controlled trial presented at the American Heart Association scientific sessions and published in the New England Journal of Medicine tested whether advanced training of 911 dispatchers, first responders and potential bystanders would improve outcomes. The study found no statistically significant increase in survival rates compared with standard practice.

The investigators cautioned that the findings do not rule out benefits from longer-term education programs or mandatory CPR training, such as those implemented in Denmark. They suggest further research to identify more effective community‑based strategies.