Sudden Cardiac Death

Heart disease is Australia's No.1 killer and it takes a precious life every 26 minutes. In many people this is sudden and without warning. Sudden cardiac death happens as a result of a cardiac arrest and can happen to people of all ages. 

There is no national registry of sudden cardiac death, but our estimates suggest around 15,000 people die unexpectedly in Australia from sudden cardiac death every year.

This equates to around 10% of all Australian deaths that occur every year (153,000).  Sudden cardiac death rates have not declined in Australia at the same rate as other heart related deaths. 

Causes

There are many causes:

  • In adults over 35, it is almost always due to coronary heart disease 
  • In younger people under 35 it can also be due to rare congenital heart conditions they sometimes aren’t aware of.

The most common cause in adults is coronary heart disease, accounting for 80% of sudden cardiac deaths overall.  The remainder are related to disease of the heart valves, disease of the heart muscle (cardiomyopathy) and inherited disorders of the heart rhythm.

Irrespective of the underlying disease the final cause of sudden cardiac death is an abnormal rhythm.  The heart may either stop beating or beat irregularly and ineffectively in a rhythm known as ventricular fibrillation (VF). 

People can be at a higher risk if a previous heart attack or inherited condition means they already have a weakened heart muscle.

Warning Signs

About a third of sudden cardiac deaths occur without any warning at all. But in many people – particularly older people with heart disease - they do experience some warning signs.

In people with coronary heart disease, cardiac arrest is often preceded by chest pain and other warning signs of heart attack.  Prompt response to chest pain may avert cardiac arrest and sudden cardiac death in people suffering a heart attack. 

Heart attack warning signs aren’t always what you think - symptoms are not always sudden or severe and some people don’t experience chest pain at all.

If the more unusual form of sudden cardiac death occurs in younger people - they might have a family history, or suffer from:

  • palpitations
  • dizziness
  • sudden fainting or seizure
  • severe headaches
  • breathlessness on exertion or chest pain

Who’s at risk?

Risk factors of coronary heart disease include; smoking, having high cholesterol, high blood pressure, diabetes, being inactive, being overweight, an unhealthy diet and depression. These risk factors are manageable and coronary heart disease can be prevented.

Heart disease is not always obvious and often there are no symptoms.

The only way to know whether you have high blood pressure or high cholesterol for example is to have a regular checkup. So the best thing you can do to find out about your risk of heart disease is to see your doctor for an annual heart health check.

In younger people who are at risk, they may have rare conditions, often inherited from someone in the family – such as hypertrophic cardiomyopathy (an inherited disease of the heart muscle, where the muscle wall of the heart becomes thickened)

  • It’s important everyone has an awareness of their family history of heart death or heart attack at a younger age.
  • There are relatively easy tests that can be done – such as an ECG (electrocardiogram).
  • Talk to a cardiologist and family doctor about the right test for you.
  • Genetic testing is also now available for many of these rare cardiac conditions.

If you have any of these symptoms, a family history and feel you’re at risk, please see your GP who can further investigate.

What to do

A person in cardiac arrest has the best chance of survival if CPR is started immediately and a ‘defibrillator’ is used on them as soon as possible. The Heart Foundation recommends that every adult and teenager learn this lifesaving skill.

There are public access defibrillators on the wall in many public places.  They can be used by anyone as they guide the operator through the necessary actions, such as delivering an electric shock to the heart to help resume the heart’s normal rhythm. 

Call Triple Zero (000) immediately so that other treatments are available before major damage to other vital organs occurs from the lack of sufficient blood and oxygen supply. 

The chance of survival reduces by 10% every minute without CPR. Continue CPR until an ambulance arrives.

 

More information

Contact the Heart Foundation Helpline to speak to one of our qualified health professionals who can provide free personalised information on 1300 36 27 87 or email health@heartfoundation.org.au

 

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