Defibrillation: What It Is and When It’s Used

Defibrillation might be utilized as an emergency technique to cease a rapid heart rate responsible for triggering low blood pressure or other significant symptoms.

Defibrillation, also known as electrical cardioversion, is a medical procedure that delivers a brief electrical shock to the heart to help restore a normal heart rhythm. The shock is delivered through adhesive pads placed on the outside of the chest or, in some cases, handheld paddles.

In hospital or controlled medical settings, individuals are typically sedated for planned defibrillation procedures. If the person is conscious, medications are given to reduce pain and anxiety so they are comfortable during the procedure.

It’s important to distinguish this from emergency defibrillation using an AED (Automated External Defibrillator), which is commonly taught in first aid and CPR training and is used during cardiac arrest.

Why Defibrillation Is Performed

Defibrillation may be used in both emergency and non-emergency situations to correct dangerous heart rhythms that interfere with effective blood circulation.

It is commonly used to treat abnormal heart rhythms such as:

Atrial fibrillation
Ventricular tachycardia
Supraventricular tachycardia

In emergency situations, defibrillation can be life-saving when a dangerously fast or irregular heart rhythm causes low blood pressure, loss of consciousness, or cardiac arrest.

What to Expect After Defibrillation

After defibrillation, healthcare providers closely monitor the individual’s:

Heart rhythm
Blood pressure
Oxygen levels

Medications may be prescribed before and after the procedure to help prevent abnormal heart rhythms from returning. In many cases, blood thinners (such as anticoagulants) are used for several weeks to reduce the risk of blood clots and stroke.

Many people return to a normal heart rhythm immediately after defibrillation, making it a highly effective treatment when used appropriately.

Possible Risks and Side Effects

While defibrillation is generally safe and effective, potential risks may include:

Dislodgement of a blood clot, which can lead to stroke
The procedure being unsuccessful, requiring repeat treatment
Abnormal heart rhythms caused by medications or the shock itself
Reactions to sedative medications
Minor skin burns where pads or paddles are placed

These risks are carefully managed by healthcare professionals in medical settings.

First Aid & AED Awareness in Canada

For the general public, defibrillation is most relevant through AED use during cardiac arrest. AEDs are designed to be safe, easy to use, and are increasingly available in workplaces, schools, recreation centres, and public spaces across Canada.

Learning CPR and AED skills empowers Canadians to respond confidently in cardiac emergencies while waiting for emergency medical services.

Disclaimer

The information provided on this page is for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. In a medical emergency, always call 911 immediately.

To learn how to recognize cardiac emergencies, use an AED, and perform CPR safely and confidently, consider taking a First Aid and CPR course with St. Mark James Training, Canada’s largest 100% Canadian-owned and operated first aid and CPR training provider.