Heart Disease 

Cardiac Arrest 


  • 20,000 Australians suffer a cardiac arrest outside a hospital every year.
  • The survival rate if you have a cardiac arrest outside of hospital is approximately 10%. 
  • The first 3-5 minutes holds the key to survival.


A sudden cardiac arrest is an electrical problem and occurs when the heart suddenly stops pumping blood. If sudden cardiac death is not treated properly and quickly, it will cause sudden death within 10 minutes.


The symptoms of sudden cardiac arrest are immediate and drastic. They include:

  • Sudden collapse
  • No pulse
  • No breathing
  • Loss of consciousness

Other signs and symptoms may occur before a sudden cardiac arrest, such as fatigue, fainting, blackouts, dizziness, chest pain, shortness of breath, weakness, palpitations or vomiting. However sudden cardiac arrest often occurs with no warning.  


The immediate cause of sudden cardiac arrest is usually an abnormality in your heart rhythm, known as an arrhythmia.

The most common cause of cardiac arrest is ventricular fibrillation, an arrhythmia where rapid, erratic electrical impulses, cause your heart chambers or ventricles, to quiver uselessly instead of pumping blood.

Deadly arrhythmias do not usually occur on their own. People with normal, healthy hearts may suffer a cardiac arrest due to an outside trigger such as an electrical shock, the use of illegal drugs or trauma to the chest at the wrong time of the heart’s cycle. 

However a cardiac-arrest-inducing arrhythmia usually develops in someone with a pre-existing heart condition. These include:

  • Coronary artery disease
  • Heart attack
  • Enlarged heart (cardiomyopathy)
  • Valvular heart disease
  • Congenital heart disease
  • Electrical problems in the heart


Sudden cardiac arrest often occurs with no warning and there is a 90% chance of death if it occurs outside a hospital. If you survive a sudden cardiac arrest, your doctor will want to investigate what caused it to identify the underlying cause. Tests may include:

  • Electrocardiogram
  • Blood tests
  • Imaging tests such as chest x-rays, echocardiogram, nuclear scan
  • Electrical system (electrophysiological) testing and mapping
  • Coronary catheterization (angiogram)
  • Genetic tests


Immediate action is required in order to survive a sudden cardiac arrest. The following steps must be taken urgently:

  • Cardiopulmonary resuscitation (CPR) – urgent CPR is critical. By maintaining a flow of oxygen-rich blood to the body’s vital organs, CPR can provide a vital link until more-advanced emergency care is available.
  • Defibrillation – A portable device which momentarily stops the heart and the chaotic rhythm, often allowing the normal heart rhythm to resume. The procedure delivers a therapeutic dose of electric currents to the heart. If a defibrillator is available, it should be used as soon as possible.

Long term treatment includes:

  • Anti-arrhythmic medication
  • Implantable cardioverter defibrillator (ICD)
  • Coronary angioplasty
  • Coronary bypass surgery
  • Radiofrequency catheter ablation
  • Corrective heart surgery


There is no definite way to know your absolute risk of sudden cardiac arrest, so reducing your overall risk is the best strategy. This includes regular check-ups at your GP, screening for heart disease and living a healthy lifestyle, for example:

  • Exercise regularly
  • Quit smoking
  • Eat a healthy diet
  • Manage weight
  • Monitor cholesterol levels
  • Monitor blood pressure
  • Manage diabetes
  • Drink alcohol only in moderation

If you have a pre-existing heart condition and are at high risk of a sudden cardiac arrest, you may need the following treatment/s:

  • Anti-arrhythmic drugs
  • Implantable cardioverter-defibrillator (ICD)
  • Purchase an automated external defibrillator (AED)
  • Ensure people around you (family, at work) know CPR

Research into Sudden Cardiac Arrest

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