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Public access defibrillation by activated community first responders – the randomized HeartRunner trial
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Key result
Smartphone-activated community first responders undergo evaluation for improving 30-day OHCA survival vs standard care.
Why the trial?
Survival after out-of-hospital cardiac arrest hinges on the minutes before ambulance arrival. HeartRunner asked whether smartphone-activated community first responders, dispatched to start CPR and fetch defibrillators, improve survival.
Does community first-responder activation via smartphone application improve 30-day survival in patients with suspected out-of-hospital cardiac arrest?
Population
2,060 emergency calls for suspected OHCA, Capital Region of Denmark
Comparison
App-dispatched community first responders + standard EMS vs standard EMS alone
Design
Investigator-initiated randomized trial, 1:1, stratified by estimated arrival time
Follow-up
30 days (primary); 1-year survival secondary
Authors
Discussion
No takes yet. Share an insight, caveat, or question.
Where experts stand
Experts view HeartRunner as a disappointing but not definitive null result, noting that community first responder activation boosted bystander CPR but failed to improve survival, and they point to system-level activation gaps rather than dismissing the concept.
The trial showed no survival benefit from app-based community first responder dispatch despite significant increases in bystander CPR and defibrillation. Experts were surprised by the null finding but largely attribute it to how the system was activated rather than a fundamental flaw in the concept. The open question is whether better activation protocols and broader deployment can translate the bystander response gains into actual survival improvement.
Agreement
Multiple experts agree that the null survival result does not close the door on community first responder programs, pointing instead to system activation and design issues as likely explanations that warrant further study.
2 clinicians say this directly
What they’re arguing about
supportiveneutralcautiouscritical
Counts are expert takes we classified by axis. Tap a row to see the takes behind its count.
Still unclear
Whether optimizing when and how often the app-based system is activated could convert the observed gains in bystander CPR into a survival benefit remains unanswered. Experts also raise the question of whether it is ethical to continue enrolling over 80,000 citizen responders without evidence that dispatch improves survival.
Key expert perspectives
PSPersia ShahriariPhysician, Copenhagen University HospitalEndpoint critiqueAug 31
An excellent system cannot improve outcomes if it is not activated enough
She argues that under-activation of the dispatch system, not a failure of the concept itself, explains the null result. If the system is not triggered as much as it should be, cardiac arrest outcomes will not change.
Distilled from their postOriginal post
LALinn AndeliusPhysician, Copenhagen Emergency Medical ServicesPractice takeAug 31
With 80,000 registered citizen responders, we must prove app dispatch improves survival
She stresses that rigorous evaluation is essential because Denmark already has over 80,000 registered citizen responders. Without evidence that dispatch actually saves lives, it is hard to justify asking volunteers to accept the physical and psychological risks of responding.
Distilled from their postOriginal post
AUAnezi UzenduCardiologist, Saint Luke's Mid America Heart InstituteResults readoutAug 31
Surprising null result, but activation flaws may explain why survival did not improve
He was surprised the trial was negative given the resuscitation community's enthusiasm for app-based bystander activation. He argues that reading deeper into potential flaws in how rescuers were activated points to ways the approach could still be improved.
Distilled from their postOriginal post
Implication
Community first-responder activation did not improve 30-day survival versus standard EMS in a short-ambulance-response region; bystander CPR and defibrillation increased.
Key Points
- Determine whether dispatching smartphone-activated community first responders alongside standard emergency medical services improves 30-day survival in out-of-hospital cardiac arrest.
- Randomized clinical trial (NCT03835403) assigning 2,060 emergency calls for suspected out-of-hospital cardiac arrest 1:1 to community first-responder activation plus standard care versus standard care alone in the Capital Region of Denmark.
- Randomization was stratified by estimated first-responder arrival time (<3 minutes vs 3 to 9 minutes) to evaluate 30-day survival, bystander cardiopulmonary resuscitation, and defibrillation rates.
- The primary endpoint of 30-day survival did not differ between the intervention and standard care arms in the <3-minute stratum (15% vs 17%, p=0.42) or the 3-to-9-minute stratum (13% vs 14%, p=0.43).
- Community activation significantly increased bystander CPR rates (86% vs 75% in the 3-to-9-minute stratum, p<0.0001) and doubled bystander defibrillation rates (14% vs 6%, p<0.0001), though return of spontaneous circulation and neurologically favourable survival did not differ.
Evidence details
What drove the result?
| Outcome | CFR + EMS | EMS alone |
|---|---|---|
| 30-day survival, <3-minute stratum | 15% | 17% |
| Primary endpoint · p=0.42 | ||
| 30-day survival, 3-9-minute stratum | 13% | 14% |
| Primary endpoint · p=0.43 | ||
| Bystander defibrillation | 14% | 6% |
| Secondary outcome · doubled with activation (p<0.0001), opposite in direction to the neutral survival result | ||
| Bystander CPR (3-9-minute stratum) | 86% | 75% |
| Secondary outcome · p<0.0001 | ||
Limitations & tradeoffs
Statistical certainty
Enrolment ended at 2,060 of the 4,188 randomisations the protocol anticipated, limiting power, and responder safety and 1-year survival results are not reported.
Design limitations
Randomisation was of emergency calls for suspected cardiac arrest rather than confirmed arrests, and ambulance response times averaging around seven minutes limited the achievable time advantage for first responders.
Structured PICO
Does community first-responder activation via smartphone application improve 30-day survival in patients with suspected out-of-hospital cardiac arrest?
P
Population
2,060 emergency calls for suspected out-of-hospital cardiac arrest (OHCA) of non-traumatic origin, outside nursing homes, in patients ≥8 years of age, in the Capital Region of Denmark.
I
Intervention
Community first-responder (CFR) activation via smartphone application (HeartRunner) to perform CPR and retrieve an AED, in addition to standard emergency response.
C
Comparator
Standard emergency response alone (CFRs not alerted).
O
Outcome
30-day survivalhard clinical
Activating community first responders via a smartphone app significantly increased bystander CPR and defibrillation rates but did not improve 30-day survival in out-of-hospital cardiac arrest.
Coverage & sources
Journal, society, and media accounts. Useful signal, not independent expert judgment.
Cite This Study
Folke et al. (2026) studied this question.
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