Automated external defibrillators (AEDs) are a type of portable, battery-operated defibrillator that detect the heart’s rhythm and issue an electric shock to restore a regular heartbeat. They are commonly found in public places like schools, offices, and sports facilities, where they can be used in an emergency to help a person who is experiencing cardiac arrest. Certain groups of people — such as those with health conditions that put them at higher risk of sudden cardiac arrest — may benefit from having an AED at home.

How do AEDs work?

Sticky pads containing electrodes are attached to the chest of the person who is experiencing cardiac arrest. A computer inside the AED receives information about the person’s heart rhythm from the electrodes. The person’s heart rhythm is analyzed and if appropriate, an electric shock is sent to the heart to help it return to a normal heartbeat.

Who might need an AED at home?

According to the Heart and Stroke Foundation of Canada, an estimated 35,000 cardiac arrests occur every year, and survival rates double if someone performs CPR and uses an AED. People with health issues that put them at a heightened risk of cardiac arrest (such as coronary heart disease) may consider having a home defibrillator. Cardiac arrest is more likely to occur in older adults, and the main risk factors for cardiac arrest in the older population are coronary heart disease and other heart conditions.

When is an AED needed?

AEDs are used to treat someone who is experiencing sudden cardiac arrest. This typically occurs when a disruption in the heart's electrical activity leads to an irregular, fast heartbeat (ventricular fibrillation) or a dangerously fast heartbeat (ventricular tachycardia). Both of these arrhythmias prevent the heart from pumping effectively and can cause it to stop beating. 

During cardiac arrest, the brain and other vital organs don't receive enough blood or oxygen. The risk of permanent damage to the brain and body increases the longer vital organs remain deprived of blood and oxygen. Cardiac arrest is often fatal unless treatment begins immediately. Administering cardiopulmonary resuscitation (CPR) after cardiac arrest can help keep blood flowing to the heart and brain, but defibrillation is often needed to bring a person’s heartbeat back to a normal rhythm.

How do you use an AED?

While all AEDs work in a similar way — by checking heart rhythm and delivering an electric shock if needed — the way they are operated can differ from model to model. The device’s user manual should be consulted for instructions related to the specific machine.

The Heart and Stroke Foundation of Canada advises that in the event of cardiac arrest, 911 should be called immediately, CPR should be administered straight away to keep blood flowing, and an AED should be used as soon as possible. After the AED has been switched on, the AED pads are attached to the person’s bare chest. All AEDs feature voice prompts to take users through the steps of administering treatment and AED pads feature illustrations to demonstrate where they should be placed. It is important that nobody is touching the person experiencing cardiac arrest once the pads have been placed and while the AED is analyzing heart rhythm or administering treatment.

Some AEDs send an electric shock to the heart automatically when necessary, but others require the user to press a button to initiate the shock. A voice prompt will notify the user if they need to press a button. If no shock is advised, CPR should be continued until emergency medical services arrive.

Do you need training to use a home defibrillator?

Many AEDs are available without a prescription, and a variety of models available today offer user-friendly features (such as visual guidance and CPR coaching) to assist individuals in helping someone who is experiencing cardiac arrest. Although training isn’t required in order to use a home defibrillator, it’s advisable for people living in the home to familiarize themselves with the AED and its functions.

For those interested in formal training, a number of organizations in Canada (such as the Canadian Red Cross) offer CPR courses that include information on how to use AEDs.

How to maintain and store an at-home AED

AEDs are believed to be most beneficial when used within three minutes of the onset of sudden cardiac arrest. It is recommended to store the home defibrillator in a central location that allows for easy, quick access. People who live in the home, caregivers, and visitors, should be made aware of where the AED is kept.

Most AEDs come with built-in self-testing processes, but some can also be tested manually — always follow the advice in the device’s user manual when performing tests. The home defibrillator, its battery, and its pads should be checked regularly and any service prompts delivered by the device should be dealt with immediately so the AED is ready in the event of an emergency. Batteries, AED pads, disposable razors (for removing chest hair), and other accessories should be stored somewhere safe and accessible.

AEDs can save lives and reduce the risk of lasting damage to the brain and body after cardiac arrest: but not all types of arrhythmias respond to AED treatment. There are other types of defibrillators — such as implantable cardioverter defibrillators (ICDs), which are surgically placed inside the body — that may be recommended to people with certain health conditions. Those considering purchasing an AED for home use due to specific health concerns may wish to consult a doctor for further guidance.