Restart a Heart: Why the Bystander Decides Who Survives
About 60,000 Canadians have a cardiac arrest outside hospital each year and most do not survive. Why the person nearby matters more than the ambulance.
Jarrett Chisholm, ACP · October 12, 2026
Friday, October 16, is World Restart a Heart Day. It exists for one reason: to get more ordinary people doing CPR and using defibrillators, because in cardiac arrest the people standing nearby do more to decide the outcome than anyone else involved.
Image needed · hero
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Community centre or school hallway. A woman in everyday clothes kneels with locked arms doing compressions on a man lying on his back (clothed; training manikin substitute acceptable). In the background a second person is jogging toward them holding a yellow or green AED case. Real lighting, determined not panicked faces.
Alt text ready: “A woman kneels over a collapsed man in a community centre hallway doing chest compressions while a second bystander runs toward them carrying a defibrillator.”
The numbers explain why. Heart and Stroke estimates that about 60,000 cardiac arrests happen outside hospital in Canada every year, and that only about one in ten of those people survives. It also says that CPR together with a defibrillator can double a person's chance of survival, and that every minute without either one cuts the chance of survival by about ten percent.
Put those two facts side by side. An ambulance in a Canadian city does well to arrive within several minutes of the call, and in rural Alberta it can be much longer. Every one of those minutes belongs to whoever is already there. If nobody acts, the minutes simply run out. If somebody pushes on the chest and somebody else brings a defibrillator, the minutes are spent keeping the brain alive until the heart can be restarted.
Image needed · diagram
survival-falls-each-minute-without-cpr-diagram.svg
A clean line chart: horizontal axis minutes 0 to 10 after collapse, vertical axis relative chance of survival. One steep line falling roughly ten percent per minute with no bystander help, and a second, much flatter line with CPR started early. Label the gap between them as the bystander's minutes. Delta gold and charcoal, no numbers beyond the axis ticks.
Alt text ready: “A simple line chart showing the chance of surviving cardiac arrest falling about ten percent for every minute without CPR or defibrillation.”
This week is about the two things that fill those minutes: CPR and the automated external defibrillator, usually called an AED.
What cardiac arrest actually is
Cardiac arrest is not the same as a heart attack, although one can cause the other. A heart attack is a blocked artery starving part of the heart muscle of blood. The person is usually awake, often in pain, and their heart is still beating. Cardiac arrest is the heart's electrical system failing so that it stops pumping altogether. The person collapses, stops responding and stops breathing normally within seconds.
In many adult cardiac arrests, the heart has not simply stopped. It is quivering in a chaotic rhythm that moves no blood. That rhythm can often be reset by an electric shock, which is what a defibrillator delivers. It cannot be reset by anything a bystander can do with their hands. CPR does not restart the heart. What CPR does is keep some blood moving to the brain and the heart itself, so that when the shock comes there is still something to save.
The chain, and where you fit in it
Resuscitation is often described as a chain: recognising the arrest and calling for help, starting CPR early, defibrillating early, then the advanced care that paramedics and hospitals give. Each link depends on the one before it. The best cardiac hospital in the province can do nothing for a person whose brain went without oxygen for ten minutes on a sidewalk.
The first three links are bystander links. They do not need a medical background, and they do not need you to be certain. They need someone willing to call, someone willing to push, and someone willing to open a defibrillator and follow its voice prompts. how to tell real breathing from the gasps that mean cardiac arrest.
What a bystander can do, in order:
- Recognise it: unresponsive, and not breathing normally. Gasping counts as not breathing normally.
- Call 911, or point at one person and tell them to call, with the phone on speaker.
- Push hard and fast in the centre of the chest, and keep going.
- Send someone for the nearest AED, turn it on, and do what it says.
Why so few people get help
Most people say they would help. Fewer do. The reasons are consistent: not recognising what is happening, being afraid of doing it wrong, being afraid of hurting the person, not knowing where the defibrillator is, and assuming someone else is more qualified. Every one of those is a training problem, and every one of them gets smaller after a few hours of hands-on practice. CPR training delivered to a whole team at your own workplace.
Some patients are helped less often than others. The Canadian edition of the 2025 resuscitation guideline highlights notes that women receive public defibrillation at significantly lower rates than men, and suggests that discomfort with exposing a woman's chest may be part of the reason. The guidelines now say it may be reasonable to adjust a bra rather than remove it to place the pads. A person in cardiac arrest is a person in cardiac arrest. The care is the same.
What this week covers
Wednesday is the AED itself: what the machine is doing when it talks to you, why it is very hard to misuse, and the handful of situations people worry about, from a wet chest to a pacemaker.
Thursday's clinical post is about what makes compressions work: the depth, the rate, and the part almost everyone forgets, letting the chest come all the way back up between pushes.
Saturday is one small job you can do this weekend: find the three defibrillators nearest to where you spend your time, before you need one.
If you have been meaning to take or renew a CPR course, this is a good week to do it. Reading will not put the feel of a compression into your hands. Practice will. the half-day CPR-A and AED certificate for adult rescue.
Quick answers
- When is World Restart a Heart Day?
- October 16. It is an international day focused on getting more bystanders to recognise cardiac arrest, start CPR and use defibrillators.
- How many people survive cardiac arrest outside hospital in Canada?
- Heart and Stroke estimates about 60,000 out-of-hospital cardiac arrests a year in Canada, with only about one in ten surviving. CPR together with a defibrillator can double a person's chance of survival.
- Is a cardiac arrest the same as a heart attack?
- No. A heart attack is a blocked artery damaging heart muscle, usually in a person who is awake. Cardiac arrest is the heart stopping pumping, and the person collapses and stops breathing normally. A heart attack can lead to cardiac arrest, which is one reason to call 911 early for chest pain.
Sources
- Heart and Stroke Foundation of Canada: About 60,000 out-of-hospital cardiac arrests occur in Canada each year and only one in ten people survive; CPR and an AED can double the chance of survival; survival falls about 10% for every minute without CPR or defibrillation. (checked 2026-09-23)
- Heart and Stroke Foundation of Canada: Canadian edition of the 2025 guideline highlights: women receive public-access defibrillation at significantly lower rates than men, and it might be reasonable to adjust a bra rather than remove it when placing pads. (checked 2026-09-23)