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What is a cardiac arrest?

Your heart


What is a cardiac arrest?

With immediate help a cardiac arrest can be survived. Learn how to save a life.

Key takeaways

2 min read

  • A cardiac arrest occurs when the heart suddenly stops beating. 

  • It is a medical emergency that can lead to death. 

  • With urgent medical care to restart the heart, survival is possible.  

  • Cardiac arrest treatment steps are: Call. Push. Shock. Call Triple Zero (000) immediately, start chest compressions and use a defibrillator (AED) if available.

Your heart is one of the most important muscles as it pumps blood all around your body. This blood is full of oxygen, which is needed by every cell in your body. A cardiac arrest occurs when the heart stops beating. That’s why it’s a medical emergency that can lead to death. 

What is cardiac arrest?

 A cardiac arrest is when your heart stops beating. This means that your brain and vital organs are starved of oxygen; you become unconscious and stop breathing or do not breathe normally. A cardiac arrest is a medical emergency.

Every minute counts when a person is in cardiac arrest. Without chest compressions and use of a defibrillator, a person in cardiac arrest will not survive.

A cardiac arrest can be survived if you get appropriate help. If you see someone in this situation, call Triple Zero (000) immediately. The call operator can talk you through what to do. Any attempt at resuscitation is better than no attempt. 

What’s the difference between a cardiac arrest and a heart attack?  

People often use these terms interchangeably, but they’re not the same. A cardiac arrest is different to a heart attack. The symptoms and management are also different. 

  • A person experiencing a heart attack will usually be alert, breathing, and complaining of chest pain or other symptoms. See heart attack warning signs for more information. 
  • If someone is having a cardiac arrest, they will not be conscious or breathing normally. They need immediate help by calling Triple Zero (000), starting chest compressions and using a defibrillator (AED).  

A heart attack can sometimes deteriorate to cause a cardiac arrest. Urgent response within 10 minutes of chest pain and/or other warning signs of heart attack starting may prevent a cardiac arrest in a person experiencing a heart attack.

It is important to call Triple Zero (000) as soon as possible if you think you see someone in cardiac arrest.

What causes a cardiac arrest?  

Your heart's electrical system controls the rate and rhythm of its pumping. A cardiac arrest is usually caused by an electrical malfunction in your heart’s electrical system that causes your heart to stop pumping. 

Certain heart conditions and events can lead to cardiac arrest if they cause a life-threatening arrhythmia (heart rhythm problem). Although heart disease is a common cause of many cardiac arrests, they may also be caused by trauma, respiratory (breathing) problems, drowning, electrocution or allergic reactions. Sometimes there’s no identifiable cause of a cardiac arrest. 

How common is a cardiac arrest? 

A cardiac arrest can happen to any of us. Most cardiac arrests that occur out of hospital occur in people’s homes, but a cardiac arrest can happen anywhere, at any time. Each year in Australia, about 25,000 people have a cardiac arrest out of hospital, and only about 10% of these people survive to leave hospital and go home.

What are the signs and symptoms of a cardiac arrest? 

A cardiac arrest happens suddenly and rapidly. It often occurs with no warning. The person in cardiac arrest will:

  • Collapse and fall to the ground 
  • Have no pulse 
  • Not breathe or breathe abnormally (gasp for air) 
  • Lose consciousness (not rousable, not aware of their surroundings and not responsive to talk or touch). 

What do you do if someone has a cardiac arrest? 

  • A cardiac arrest is a medical emergency. If a person has a cardiac arrest, they will not be conscious or breathing normally. They need your immediate help by calling Triple Zero (000), starting chest compressions and using a defibrillator (AED).

Every minute counts when a person is in cardiac arrest. You don’t have to be a trained paramedic to help save a life. Any bystander (even with no training) can improve the likelihood of a cardiac arrest patient surviving by taking three key steps. 

Responsive Table


Call Triple Zero (000). Request an ambulance.


Compressions-Only CPR (Cardiopulmonary Resuscitation).
Push hard and fast in the centre of the chest.


Use an AED. Provide rapid defibrillation. Anyone can use a defibrillator, as the device gives voice instructions to tell you what to do.

The rescuer should continue CPR until the ambulance arrives. Remember the Triple Zero (000) operator will guide you through what to do.

What is CPR (Cardiopulmonary Resuscitation)?

Cardiopulmonary Resuscitation (CPR) is a combination of mouth-to-mouth rescue breathing and chest compressions. CPR helps to keep blood and oxygen circulating to the brain of a person whose heart has stopped beating, until the heart can be restarted. CPR alone does not restore a normal heart rhythm.

Compressions-Only CPR (COCPR) is CPR without rescue breaths (also known as ‘hands only CPR’). Both types of CPR double the patient’s survival rates. 

What is a defibrillator (AED or Automated External Defibrillator)? 

An automated external defibrillator (AED) is a portable electronic device that diagnoses life-threatening abnormal heart rhythms that can cause a cardiac arrest.

An AED might be able to treat these abnormal heart rhythms by giving an electric shock to try to ‘restart’ the heart to its normal rhythm. This is known as defibrillation.

An automated external defibrillator (AED) will only give a shock if it is necessary. 

You cannot do any harm by using an automated external defibrillator (AED) on someone who is unconscious. 

 Life after cardiac arrest

 After a cardiac arrest, your doctor will try to discover its cause. Your doctor will also discuss treatment options with you to reduce your risk of having another cardiac arrest.  Life after a cardiac arrest will depend on:
  • If the survivor had brain damage and how much 

  • Time between collapse and the start of CPR/defibrillation 

  • Quality of CPR/defibrillation 

  • When brain activity restarted after the cardiac arrest

There are people who have survived a cardiac arrest and gone on to live a healthy, fulfilling life because of the immediate action taken by a bystander calling Triple Zero (000), starting chest compressions and using a defibrillator (AED). 

Watch David’s cardiac arrest survivor story

  • Beck B, Bray J, Cameron P, et al. Regional variation in the characteristics, incidence and outcomes of out-of-hospital cardiac arrest in Australia and New Zealand: Results from the Aus-ROC Epistry. Resuscitation. May 2018;126:49-57. doi:10.1016/j.resuscitation.2018.02.029
  • Ambulance Victoria. Call Push Shock.

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Last updated24 January 2024