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Heart Attack (Myocardial Infarction)

The most common cause of a heart attack is coronary artery disease and is also known as a myocardial infarction (MI)

Heart needs a good blood supply to function. A  heart attack  occurs if an artery supplying blood to the heart gets blocked. This stops the blood flow to the heart muscle which may get damaged if the blood supply is not restored quickly. The longer the blockage is left untreated the more the damage occurs. Without urgent treatment to restore the blood flow, the damage can be permanent. 

A heart attack can be fatal. Each day, an average of 21 Australians die from a heart attack. One patient is admitted to an Australian hospital with a heart attack every nine minutes (source: national heart foundation):

The most common heart attack symptoms are chest discomfort, chest pain, or chest heaviness, which can spread to your arms, neck, jaw or back. Unlike angina this discomfort often last for longer than 10 minutes

What causes a heart attack? 


The most common cause of a heart attack is coronary artery disease. This occurs when the coronary artery (the artery supplying blood to your heart muscle), narrows due to a build-up of plaque over time.


Plaque is made of fat, cholesterol and other materials.


The narrowed artery causes a reduced amount of blood flow to your heart muscle.  

During a heart attack, plaque from the artery wall breaks away (ruptures) and forms a clot. This can block the flow of blood through the artery and cause damage to the heart muscle. 

Some heart attacks are caused when a coronary artery contracts (spasms) and narrows. Like coronary heart disease, this also reduces or stops blood flow reaching your heart. If an artery has a severe spasm, it can cause a heart attack.  


A heart attack can also be caused by the tearing of the coronary artery wall. This is called a spontaneous coronary artery dissection. This may be due to an underlying medical condition.

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Cardiac arrest is different from heart attack and  occurs when your heart stops beating. This may be due to a heart attack or due to an electrical problem such as arrhythmia.

A person in cardiac arrest will be unconscious and will not be breathing. This is a medical emergency. If the heart is not restarted immediately, cardiac arrest can lead to brain damage and death. Immediate CPR is required. 


If you witness a cardiac arrest call 000 immediately. 

Cardiac Arrest
Who Is At Risk?


In men, the risk for heart attack increases significantly after the age of 45. In women, heart attacks are more likely to occur in the years after menopause (usually, after the age of 50). However, younger men and women can also have heart attacks.


Besides age, factors that increase the risk for heart attack are:

  • A previous heart attack or procedure to open up the coronary arteries

  • Family history of early heart disease: Father or brother diagnosed before age 55, mother or sister diagnosed before age 65

  • Diabetes mellitus

  • High blood cholesterol

  • High blood pressure

  • Cigarette smoking

  • Overweight

  • Physical inactivity


Symptoms Vary for Women


Women tend to experience heart attacks about ten years later in life than their male-counterparts. Also, women are twice as likely to die within few weeks of suffering a heart attack. 


There are a number of things one can do to help lower the risk of having a heart attack, including being physically active, adopting a health diet and managing your weight and stress levels. 

If you have one or more of these factors, see your doctor to find out how to reduce your risk of having a heart attack.

Timing is everything!
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