Heart attack

The heart is one of your most important muscles, pumping blood that carries oxygen and nutrients to every part of your body. To work properly, the heart needs a good blood supply of its own. A heart attack, also known as a myocardial infarction (MI), happens when one or more of the arteries supplying the heart muscle becomes blocked. This stops the blood flow and reduces the oxygen reaching the heart muscle.

Recognising the warning signs and calling for help quickly could save your life or someone else’s. The longer a blockage is left untreated, the more damage occurs, so early treatment is vital and everyone should know the warning signs.

Warning signs of a heart attack#

During a heart attack you may feel pain, pressure, heaviness or tightness in one or more parts of your upper body, including the:

• chest
• shoulder
• neck
• arm
• jaw
• back

This may occur with other warning signs, such as:

• shortness of breath or difficulty breathing
• nausea, indigestion or vomiting
• dizziness, light-headedness or feeling faint
• sweating or breaking out in a cold sweat

You may have just one of these signs or several. They usually last at least 10 minutes, and may come on suddenly or get worse over time.

Chest pain or discomfort is the most common warning sign, but some people have no chest pain at all, and others have only mild discomfort. Warning signs can differ for women: although chest pain is the most common sign in both women and men, women are more likely than men to have the non-chest symptoms above, along with feeling fatigued or tired.

It is also possible to have a “silent heart attack” with few or no symptoms, which may not be picked up until later.

If you or someone you know has the warning signs of a heart attack, tell someone. If the symptoms are severe, getting worse, or last more than 10 minutes, call your local emergency number immediately and ask for an ambulance.

Causes of a heart attack#

The most common underlying cause is coronary heart disease. This occurs when fatty deposits (called plaque or atheroma) slowly build up on the inner wall of the coronary arteries, causing them to narrow. During a heart attack, plaque from the artery wall breaks away (ruptures) and can form a clot. The clot blocks blood flow through the artery and damages the heart muscle.

Less common causes include:

• coronary artery spasm – a sudden narrowing or contraction of a coronary artery
• spontaneous coronary artery dissection – a tearing of the coronary artery wall

To find out your own risk of having a heart attack, see your doctor for a heart health check.

Diagnosing a heart attack#

A heart attack is a medical emergency, and diagnosis and treatment can begin in the ambulance. At hospital, further tests confirm the heart attack, measure the amount of damage, and guide treatment. Tests may include:

• an electrocardiogram (ECG) to measure the electrical activity of your heart
• blood tests, including a troponin test that measures proteins released into the blood when heart muscle is damaged
• a coronary angiogram, in which a long, thin tube (catheter) is inserted into an artery in the wrist (or sometimes the groin) and threaded up to the heart; dye is injected and an X-ray shows where the coronary arteries are blocked

Treatment for a heart attack#

A heart attack needs emergency treatment to restore blood flow to the heart – the faster this happens, the less damage occurs. Treatment may involve medicines, surgery, or both.

One treatment is thrombolysis (thrombolytic therapy), in which a “clot-busting” medicine is given through a drip to dissolve the clot narrowing or blocking the artery. Dissolving the clot improves blood flow to the heart muscle and around the body.

To reduce the risk of future heart attacks, your doctor will usually start you on medicines while you recover in hospital, which you will need to keep taking long term. Do not stop them unless your doctor or cardiologist tells you to, and have regular check-ups so your medicines can be reviewed and adjusted. Commonly prescribed medicines after a heart attack include:

• antithrombotic medicines such as anticoagulants and antiplatelets, to reduce the risk of blood clots forming
• blood pressure medicines such as ACE inhibitors and angiotensin II receptor blockers (ARBs), which widen blood vessels and make it easier for the heart to pump
• beta blockers, to lower blood pressure and regulate heart rate and rhythm
• cholesterol-modifying medicines, to reduce cholesterol levels

Some people need surgery to open a blocked artery. This may include:

• coronary angioplasty and stent insertion – a balloon is used to open the blocked artery; once it is open, an expandable tube (stent) is left in place to keep it open and the balloon is withdrawn
• coronary artery bypass graft (CABG) surgery – a healthy blood vessel (a vein or artery from the arm, leg or chest) is attached on either side of the blockage so blood can flow to the heart again

Recovering from a heart attack#

A heart attack can be a life-changing event, and it is normal to feel scared, confused or overwhelmed afterwards. Having one heart attack increases your risk of having another, but there is a lot you can do to recover and lower that risk.

Cardiac rehabilitation is a program of support, exercise and education led by health professionals. It helps you recover, return to a full and active life, and make long-term lifestyle changes that improve your heart health. Ask your doctor about a local program suited to your needs.

Take your medicines as prescribed. Medicines help protect your heart and lower the risk of future problems. For more information, speak to your doctor or pharmacist. Always check with your doctor before taking other medicines you buy over the counter (from a pharmacy, supermarket or health food shop without a prescription), because many – including some pain, cold and flu medicines, supplements and vitamins – can interact with your heart medicines.

Make heart-healthy lifestyle changes, including:

• quitting smoking and limiting exposure to second-hand smoke
• being physically active most days of the week
• following a heart-healthy eating pattern
• drinking less alcohol
• looking after your mental health
• maintaining a healthy body weight
• managing your blood pressure and cholesterol
• managing your blood sugar levels, if you have diabetes

Join a support group. Connecting with others who have had a similar experience can offer practical advice and emotional support.

Key points#

• A heart attack is a medical emergency – call your local emergency number immediately if warning signs are severe, worsening, or last more than 10 minutes.
• Warning signs include pain, pressure or tightness in the chest, shoulder, neck, arm, jaw or back, often with shortness of breath, nausea, dizziness or cold sweats; women more often have the non-chest signs.
• The most common cause is coronary heart disease, where plaque ruptures and forms a clot that blocks blood flow to the heart muscle.
• Diagnosis and treatment can start in the ambulance, and faster treatment means less heart damage.
• After a heart attack, cardiac rehabilitation, taking medicines as prescribed and a heart-healthy lifestyle help reduce the risk of another.

Where to get help and trusted information#

For evidence-based global health guidance, see Source: World Health Organization (WHO).