What is a heart attack?

The heart is a muscular pump that’s a little larger than your fist. It’s one of your most important muscles as it pumps blood all over your body through the circulatory system. 

Your blood carries oxygen, which is needed by every cell in your body, all the time. Your heart pumps oxygen-rich blood from the lungs to the heart, and then on to the rest of the body.

What is a heart attack? 

For your heart to function properly, it needs a good blood supply. A heart attack occurs when a coronary artery, which supplies blood to your heart, becomes blocked. This stops the blood flow and reduces the amount of oxygen that gets to your heart muscle. This causes the most common heart attack symptoms, which are chest discomfort or pain and can spread to your arms, neck, jaw or back. Unlike angina this discomfort often last for longer than 10 minutes

Your heart can be damaged by interrupted blood flow caused by a heart attack. 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.  

If you, or someone you know, is experiencing heart attack symptoms for greater than 10 minutes of rest, or if symptoms are severe, or they are getting worse, call Triple Zero (000) immediately. 

A heart attack can also be called a myocardial infarction (MI).

What causes a heart attack? 

The most common cause of a heart attack is coronary heart disease. This occurs when the coronary artery, which supplies blood to your heart, narrows because of a build-up of plaque. 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 can form a clot. This can block the flow of blood through the artery and cause damage to the heart muscle. 

Other causes of heart attack besides blockage 

Not all heart attacks are caused by coronary heart disease and plaque rupture. 

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 (spontaneous coronary artery dissection). 

What is the difference between heart attack and cardiac arrest? 

Heart attack 

A heart attack occurs when an artery supplying blood to your heart becomes blocked, which stops blood flow and reduces the amount of oxygen that gets to your heart.  

A person having a heart attack is usually conscious and may be complaining of chest discomfort or pain or other symptoms.  

Cardiac arrest  

A cardiac arrest occurs when your heart stops beating due to an electrical malfunction.  

A person in cardiac arrest will be unconscious (not able to respond) and will not be breathing. This is because their heart has suddenly stopped beating and blood can no longer flow to the brain, heart and lungs.  

A cardiac arrest is a medical emergency. If the heart is not restarted immediately, cardiac arrest can lead to brain damage and then death. Every second counts. If you witness a cardiac arrest call Triple Zero (000) immediately. Giving chest compressions and using a defibrillator (AED) can improve a person’s chances of survival.

Heart attack warning signs and symptoms  

Recognising the symptoms of a heart attack and calling Triple Zero (000) could save your life or the life of a loved one. It’s important that everyone, both male and female, know the warning signs and symptoms of a heart attack, because early treatment is vital. The longer a blockage is left untreated, the more damage occurs.        

The most common heart attack warning signs are:  

• Chest discomfort or pain (angina). This can feel like uncomfortable pressure, aching, numbness, squeezing, fullness or pain in your chest. This discomfort can spread to your arms, neck, jaw or back. It can last for several minutes or come and go 
• Dizziness, light-headedness, feeling faint or feeling anxious 
• Nausea, indigestion, vomiting 
• Shortness of breath or difficulty breathing – with or without chest discomfort 
• Sweating or a cold sweat.    

Download our heart attack warning signs action plan

How do you know if you’re having a heart attack and not something less serious?

Heart attack symptoms can be different for each person. No two heart attacks are the same, even for the same person. You may have just one, or a combination of symptoms. Sometimes the symptoms of a heart attack are not the classic ‘crushing chest pain’ you may expect. 

You may feel less obvious symptoms, such as a burning feeling in your chest and shortness of breath. Sometimes you may have no ‘warning sign symptoms’ at all. In fact, your doctor may even discover that you have had a silent heart attack. 

A heart attack can only be diagnosed by medical tests. The only way to know what you’re experiencing is to seek urgent help. At worst, you may have something less serious. At best, you will receive the treatment that you need.  

Do not ignore the warning signs of a heart attack. Every minute counts. Download our heart attack action plan. 

If you’re experiencing the warning signs of a heart attack or are worried you or someone you know is having a heart attack – tell someone. If symptoms are severe, or getting worse, or last for more than 10 minutes, call Triple Zero (000) immediately.  

How can you reduce your risk of having a heart attack?  

Knowing your risk of coronary heart disease is the first step to reducing your risk of having a heart attack. Yet many people don’t know that they are at risk. More than two thirds of Australian adults, or 12 million people, have three or more heart attack risk factors¹. 

The best way to find out your risk of having a heart attack is to see your GP for a heart health check if you are over the age of 45 (or 30 for Aboriginal and Torres Strait Islander people). 

You can reduce your risk by making positive changes to your lifestyle with the help of your doctor. 

How is a heart attack diagnosed? 

A heart attack is a medical emergency. If you’re experiencing the symptoms of a heart attack, call Triple Zero (000) and ask for an ambulance. An ambulance is the safest way to go to hospital and the quickest way to seek treatment. Treatment can start when ambulance staff arrive, saving precious minutes and preventing damage to your heart muscle. 

Once you get to hospital, your doctor will perform tests to diagnose if you’re having a heart attack.  

These tests will also measure the amount of damage caused to your heart and the best treatment course to take.

These tests include: 

• Electrocardiogram (ECG) 
• Blood tests 
• Coronary catheterisation (angiogram) 

How is a heart attack treated? 

A heart attack requires emergency treatment to restore blood flow to your heart. The faster this happens, the less the heart muscle is damaged. Heart attack treatments may involve medications or surgery.