Understanding Sudden Cardiac Arrest

Here’s what you need to know about this medical emergency.

Sudden cardiac arrest, sometimes called cardiac arrest or SCA, is one of Australia’s biggest causes of death and disability. It affects an estimated 33,000 Australians each year. But immediate CPR and defibrillation in the first few minutes may reverse a sudden cardiac arrest to save a person’s life and reduce any long-term neurological impairment.

What is cardiac arrest?

A cardiac arrest is when your heart suddenly stops beating. 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. When your heart stops, it starves your brain and vital organs 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. Any attempt at resuscitation is better than no attempt.

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 and New Zealand, about 33,000 people have a cardiac arrest out of hospital, but it’s estimated that as few as 5% 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 breathing or breathing abnormally 
  • Lose consciousness (not rousable, not aware of their surroundings and not responsive to talk or touch).

How do you treat sudden cardiac arrest?

Following the steps in the Chain of Survival provides the best chance of survival from sudden cardiac arrest, including early use of a defibrillator to shock the heart back into a normal rhythm.

Want to be heart safe?

Get an AED and be shock ready

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