What is a heart attack?

A heart attack happens when there is a sudden loss of blood flow to part of the heart muscle. This is usually caused by a blockage in one or more of the heart's blood vessels, which are called coronary arteries. These arteries deliver blood and oxygen to your heart.

When an artery is blocked, your heart muscle doesn't get enough oxygen. This means it can't pump blood to the rest of your body.

A heart attack is also known as a myocardial infarction.

A heart attack is a medical emergency. Without enough oxygen, your heart muscle can be permanently damaged.

In Australia, almost 1 in 50 people will experience a heart attack during their life.

Is a cardiac arrest the same as a heart attack?

A cardiac arrest and a heart attack are both medical emergencies. However, they are not the same thing.

A heart attack is where a blocked artery reduces blood flow to the heart muscle. It causes chest pain and breathing difficulties but the heart can usually continue to beat. Sometimes a heart attack can lead to a cardiac arrest.

A cardiac arrest is where there is a problem with the electrical signals that tell your heart to beat. Your heart stops beating or doesn't beat properly. This leads to unconsciousness ('passing out') and loss of breathing. Immediate treatment is needed to get your heart working again.

What are the symptoms of a heart attack?

If you have chest pain, difficulty breathing or palpitations, or feel faint, sweaty or unwell, you could be having a heart attack. Call triple-zero (000) immediately and ask for an ambulance if symptoms are severe, getting worse or last longer than 10 minutes.

Heart attack symptoms can vary from person to person. Some people do not have any symptoms. You may have mild chest pain or no chest pain at all, or for the pain to come and go.

Symptoms of a heart attack may include:

• chest pain — pressure, heaviness, tightness, squeezing or a crushing feeling in the middle of your chest
• pain in other areas such as your arms, shoulders, back, neck, jaw or stomach
• coughing, a choking sensation or difficulty breathing
• suddenly feeling dizzy, faint, light-headed or anxious
• nausea or vomiting
• a feeling of indigestion
• sweating or a cold sweat
• irregular or fast heartbeat (palpitations)

Heart attack symptoms in females

Females are less likely than males to have chest pain. They may experience:

• pain in the back, neck, jaw or both arms
• shortness of breath or nausea
• feeling very tired
• pressure or a tight feeling in the chest

What are the warning signs?

When should I call an ambulance or go to the emergency department?

If you think you or someone else may be having a heart attack, call triple-zero (000) right away and ask for an ambulance. Early treatment could save a life.

What should I do while waiting for the ambulance?

If you are having symptoms of a heart attack, you should:

• chew aspirin — take 300 milligrams of aspirin (unless you are allergic to it). Chewing aspirin during a heart attack can help reduce heart damage.
• take glyceryl trinitrate — if your doctor has prescribed this medicine for an existing heart condition, take it as directed.

If someone is unconscious or not breathing, call for help and start CPR immediately. If available, use a defibrillator.

Do not drive if you're having a heart attack. If no ambulance is available, ask a bystander or neighbour to take you to the hospital.

What causes a heart attack?

The most common cause of a heart attack is coronary artery disease.

This happens when the arteries of the heart narrow or get blocked by plaque. Plaque is made up of fat, cholesterol and other substances. If the plaque bursts, a blood clot can form. This blocks the flow of blood and oxygen to your heart muscle, causing damage.

Other causes of a heart attack include:

• coronary artery embolism — a blood clot from another part of the body blocks the coronary artery
• coronary vasospasm — a sudden narrowing or tightening of the coronary artery, which reduces blood flow to your heart
• aortic dissection — a sudden tear in the wall of your aorta

Risk factors

Certain lifestyle factors can increase your risk of a heart attack.

Risk factors you can't change include:

• age — as you get older, your risk of a heart attack increases
• sex — males are more likely to have heart attacks than females
• family history — if heart disease runs in your family, your chances of having a heart attack are higher

Risk factors you can change or manage include:

• smoking
• high cholesterol
• diabetes
• high blood pressure
• not getting enough physical activity
• living with obesity or overweight
• eating an unhealthy diet high in saturated fats, salt and sugar

Other health conditions can increase your chance of having a heart attack, such as hyperthyroidism and severe anaemia. Getting the flu or COVID-19 can also lead to a heart attack.

How is a heart attack diagnosed?

Your doctor will diagnose a heart attack by asking about your symptoms and doing tests. They will also check your vital signs, such as your blood pressure, pulse and temperature.

Tests to confirm a heart attack and check for any damage to your heart include one of more of the following:

• Electrocardiogram (ECG) — small pads with wires are placed on your chest, arms and legs. This measures electrical signals travelling through your heart muscle.
• Cardiac troponin test — this blood test checks for a protein called troponin, which is released when your heart muscle is damaged.
• Chest x-ray — to rule out other causes of your symptoms.
• Angiography (cardiac catheterisation) — a small tube is inserted into an artery in your groin or wrist and guided to your heart. A special dye is injected to show if there is a narrowing or blockage.
• Echocardiogram — an ultrasound scan of your heart.
• CT scan or MRI scan of the heart — these tests take detailed pictures of your heart to check for damage or problems.

How is a heart attack treated?

When treating a heart attack, it is important to get blood flowing again to your heart quickly. The longer your heart is without oxygen, the more damage there will be.

Medicines

Medicines are given as soon as possible to help restore blood flow and prevent further damage. They can also help prevent another heart attack.

Medicines include:

• aspirin — this thins the blood, preventing blood clots forming or getting bigger
• thrombolytics — a medicine to dissolve the blood clot in your blocked coronary artery
• nitrate medicines (such as glyceryl trinitrate) — to improve blood flow through the coronary arteries
• blood pressure medicines ( ACE inhibitors, angiotensin II receptor blockers and beta blockers) — these lower the strain on your heart and help it work better
• cholesterol-lowering medicines — to lower the cholesterol in your blood and prevent another heart attack
• pain relievers

Surgical procedures

Treatments that can restore blood flow to your heart include the following:

• Angioplasty — a small balloon is inserted into the blocked artery and inflated to open it. A stent (a tiny mesh tube) may be left in the artery to keep it open.
• Coronary artery bypass graft surgery (CABG) — this involves taking a healthy blood vessel from somewhere else in your body and attaching it to the blocked artery on each side of the blockage. This lets blood flow around the blockage.

Life after a heart attack

After the heart attack is treated, ongoing treatment focuses on recovery and prevention of further heart attacks.

Cardiac rehabilitation is a program of education and exercise. It provides support during your recovery and helps lower your risk of having another heart attack. It will help you make lifestyle changes (such as starting a healthy diet, quitting smoking and managing stress) to help prevent another heart attack.

What are the complications of a heart attack?

Complications can be serious and may include:

• lack of blood flow — this can lead to another heart attack or ongoing chest pain (angina)
• arrhythmias — your heart may develop an abnormal heartbeat due to damage
• heart failure
• cardiogenic shock — a life-threatening condition where your heart suddenly can't pump enough blood to your body
• heart rupture — where part of your heart tears open
• blood clots
• pericarditis — inflammation of the lining around the heart

Can a heart attack be prevented?

Making healthy lifestyle changes is the best way to lower your risk of a heart attack.

Here are some tips to improve your heart health:

• Quit smoking.
• Eat a healthy diet.
• Stay physically active and exercise regularly.
• Maintain a healthy weight.
• Don't drink too much alcohol.
• Reduce stress.

See your doctor to check your blood pressure, blood sugar and cholesterol. Your doctor can help you manage these to prevent a heart attack.

Get vaccinated against COVID-19 and the flu to help protect yourself and others.

Resources and support

The Heart Foundation offers resources about:

• how your heart works
• recognising a heart attack
• support after a heart attack
• relationships and sex after a heart attack
• caring for someone who has had a heart attack

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available 24 hours a day, 7 days a week.

Do you prefer to read in languages other than English?

The Heart Foundation has fact sheets on heart health translated into more than 25 community languages.

The Heart Foundation has a video about the warning signs of a heart attack in several community languages.

Looking for information for Aboriginal and/or Torres Strait Islander people?

HealthInfoNet provides advice on cardiovascular health for Aboriginal and/or Torres Strait Islander people.