App alerts heroes: volunteers with defibrillators rush to cardiac arrests
NCT ID NCT03835403
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tested whether using a smartphone app to alert nearby volunteers (called 'heart runners') to bring an automated external defibrillator (AED) to a suspected cardiac arrest can improve survival. Over 2,000 emergency calls were randomly assigned to either activate these volunteers or provide standard emergency medical services alone. The main goal was to see if more patients were alive 30 days later, and the study also checked for any harm to the volunteers.
What this could mean
Our plain-language read of the trial. This is informational only — not medical advice or a prediction.
- Active substance
- Smartphone app activation of volunteer citizen first-responders with AEDs
- What this could lead to
- If successful, this approach could significantly increase survival rates for out-of-hospital cardiac arrest by getting defibrillators to patients faster.
- What could go wrong
- The trial is completed but results may show no survival benefit, and there are risks of psychological or physical harm to volunteer responders.
This is an AI summary of the original study and may miss details. Read our disclaimer.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Emergency Medical Services Copenhagen
Copenhagen, Ballerup, Denmark
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