Article posted on May 8, 2025
The cardiac arrest chain of survival and the importance of early recognition
The patient journey after experiencing cardiac arrest is often referred to as the “Chain of Survival.” This represents a series of critical actions that contribute to survival and recovery for a person who has experienced sudden cardiac arrest. The involvement of both bystanders and medical professionals plays a vital role in patient survival.
A common idiom emphasizes that a chain is only as strong as its weakest link, and this also true of the chain of survival. After sudden cardiac arrest occurs, the patient’s survival rate can drop by 7-10% for every minute that passes without intervention.¹
Early bystander intervention is one of the most significant factors impacting patient survival. By quickly calling 9-1-1, starting CPR and retrieving a nearby AED (automated external defibrillator), bystanders can not only increase the patient’s chance of survival but also help ensure better outcomes with less likelihood of long-term damage to vital structures such as the heart and brain.
What does cardiac arrest look like?
It’s important to recognize the signs of sudden cardiac arrest. The patient may suddenly collapse or become unresponsive, and they will not be breathing or are breathing ineffectively which is called agonal respirations. Agonal respirations may sound like gasps, snoring, moaning and may appear irregularly and shallow. These respirations are not effectively providing oxygen to vital organs. Patients demonstrating agonal respirations are not considered to be breathing.
Cardiac arrest can appear like a seizure because of the body’s reaction to the sudden arrest and lack of oxygen. However, the lack of effective breathing is a clear sign of the need for immediate medical attention. In these instances, it is better to err on the side of caution and assume cardiac arrest in order to not waste precious time in the chain of survival.
If a person is believed to be experiencing cardiac arrest, it is vital to immediately call 9-1-1 and begin CPR. When the dispatcher asks, it is important to clarify that the patient is not awake and not breathing. The dispatcher will instruct the caller to start CPR if they haven't already done so. For bystanders who are unfamiliar with CPR, trained emergency medical dispatchers will coach them through the steps.
The Heart Safe registry tracks AED locations across the province. When a patient is in cardiac arrest, the dispatcher can find the location of the nearest registered AED and direct bystanders to go retrieve it if the device is within close proximity to the medical emergency.
An AED can aid in restoring a functional heart rhythm by delivering a shock to the heart. AEDs are safe, easy to use devices that emit audible instructions, guiding the rescuer through the steps to help the patient in cardiac arrest. Using an AED can significantly increase the patient’s odds of survival.
It’s important to remember that you don’t need to be a medical professional to save a life. Calling 9-1-1, starting CPR and using an AED can empower everyday people to become lifesavers. By strengthening the links in the chain of survival, you are supporting a better cardiac arrest outcomes in your community.
If you’d like to be better prepared to act during a medical emergency, CPR and first aid training is available across the province. While this is not required for bystanders to help, it can enable you to act more confidently during the event. You can find a list of approved training providers here.
If you have an AED at your workplace and wish to register it with the Heart Safe registry, please click here.
¹ Ibrahim WH. Recent advances and controversies in adult cardiopulmonary resuscitation. Postgrad Med J. 2007;83(984):649-654. doi:10.1136/pgmj.2007.057133
Last Updated: Thursday, May 08, 2025