Heart attack

A heart attack (myocardial infarction or MI) is a serious medical emergency in which the supply of blood to the heart is suddenly blocked, usually by a blood clot.

A heart attack is a medical emergency. Call 999 and ask for an ambulance if you suspect a heart attack.

A lack of blood to the heart may seriously damage the heart muscle and can be life threatening.

Symptoms of a heart attack

Symptoms of a heart attack can include:

  • chest pain – the chest can feel like it's being pressed or squeezed by a heavy object, and pain can radiate from the chest to the jaw, neck, arms and back
  • shortness of breath 
  • feeling weak or lightheaded, or both
  • an overwhelming feeling of anxiety

It's important to know that not everyone experiences severe chest pain. This is particularly the case with many women. The pain can often be mild and mistaken for indigestion.

It's the combination of symptoms that's important in determining whether a person is having a heart attack and not the severity of chest pain.

Treating heart attacks

While waiting for an ambulance, it may help to chew and then swallow a tablet of aspirin (ideally 300mg), as long as the person having a heart attack is not allergic to aspirin.

Aspirin helps to thin the blood and improves blood flow to the heart.

In hospital, treatment for a heart attack depends on how serious it is.

The 2 main treatments are:

  • using medicines to dissolve blood clots
  • surgery to help restore blood to the heart

Causes of a heart attack

Coronary heart disease (CHD) is the leading cause of heart attacks.

CHD is a condition in which the major blood vessels that supply the heart get clogged with deposits of cholesterol, known as plaques.

Before a heart attack, 1 of the plaques bursts (ruptures), causing a blood clot to develop at the site of the rupture.

The clot may block the supply of blood to the heart, triggering a heart attack.

Recovering from a heart attack

The time it takes to recover from a heart attack will depend on the amount of damage to your heart muscle.

Most people can return to work after having a heart attack. Some people are well enough to return to work after 2 weeks. Other people may take several months to recover. How quickly you can go back to work depends on your health, the state of your heart and the type of work you do.

The recovery process aims to:

  • reduce your risk of another heart attack through a combination of lifestyle changes (such as eating a healthy diet), and medicines (such as statins), which help to lower blood cholesterol levels
  • gradually restore your physical fitness so you can resume normal activities (cardiac rehabilitation)

Find out more about recovering from a heart attack

Complications of a heart attack

Complications of a heart attack can be serious and possibly life threatening.

These include:

  • arrhythmias – these are abnormal heartbeats. 1 type is where the heart begins beating faster and faster, then stops beating (cardiac arrest)
  • cardiogenic shock – where the heart's muscles are severely damaged and can no longer contract properly to supply enough blood to maintain many body functions
  • heart rupture – where the heart's muscles, walls or valves split apart (rupture)

These complications can happen quickly after a heart attack and are a leading cause of death.

Many people die suddenly from a complication of a heart attack before reaching hospital or within the 1st month after a heart attack.

The outlook often depends on:

  • age – serious complications are more likely as you get older
  • the severity of the heart attack – how much of the heart's muscle has been damaged during the attack
  • how long it took before a person received treatment – treatment for a heart attack should begin as soon as possible

Find out more about complications of a heart attack

Preventing a heart attack

There are 5 main steps you can take to reduce your risk of having a heart attack (or having another heart attack):

  • smokers should quit smoking
  • lose weight if you're overweight or obese
  • do regular exercise – adults should do at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity each week, unless advised otherwise by the doctor in charge of your care
  • eat a low-fat, high-fibre diet, including wholegrains and at least 5 portions of fruit and vegetables a day
  • moderate your alcohol consumption
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If you suspect the symptoms of a heart attack, call 999 immediately and ask for an ambulance.

Do not worry if you have doubts. Paramedics would rather be called out to find an honest mistake has been made than be too late to save a person's life.

Symptoms of a heart attack can include:

  • chest pain – a sensation of pressure, tightness or squeezing in the centre of your chest
  • pain in other parts of the body – it can feel as if the pain is travelling from your chest to your arms (usually the left arm is affected, but it can affect both arms), jaw, neck, back and tummy (abdomen)
  • feeling lightheaded or dizzy
  • sweating
  • shortness of breath
  • feeling sick (nausea) or being sick (vomiting)
  • an overwhelming sense of anxiety (similar to having a panic attack)
  • coughing or wheezing

Although the chest pain is often severe, some people may only experience minor pain, similar to indigestion. In some cases, there may not be any chest pain at all, especially in women, older people, and people who have diabetes.

It's the overall pattern of symptoms that helps to determine whether you are having a heart attack.

Waiting for an ambulance

If you have had a heart attack, it's important that you rest while you wait for an ambulance, to avoid unnecessary strain on your heart.

If aspirin is available and you are not allergic to it, slowly chew and then swallow an adult-size tablet (300mg) while you wait for the ambulance.

Aspirin helps to thin your blood and improve blood flow to your heart.

Cardiac arrest 

In some cases, a complication called ventricular arrhythmia can cause the heart to stop beating. This is known as sudden cardiac arrest.

Signs and symptoms that suggest a person has gone into cardiac arrest include:

  • they appear not to be breathing
  • they're not moving
  • they don't respond to any stimulation, such as being touched or spoken to

If you think somebody has gone into cardiac arrest and you do not have access to an automated external defibrillator (AED), you should perform chest compressions, as this can help restart the heart.

Chest compression

To do chest compressions on an adult:

  1. Place the heel of your hand on the breastbone at the centre of the person's chest. Place your other hand on top of your first hand and interlock your fingers.
  2. Using your body weight (not just your arms), press straight down by 5 to 6cm on their chest.
  3. Repeat this until an ambulance arrives.

Aim to do 100 to 120 compressions a minute. Watch the video on "hands-only" CPR from the British Heart Foundation.

Find out about how to resuscitate a child.

Automated external defibrillator (AED)

If you have access to an AED, you should use it. An AED is a safe, portable electrical device that most large organisations keep as part of first aid equipment.

It helps to establish a regular heartbeat during a cardiac arrest by monitoring the person's heartbeat and giving them an electric shock if necessary.

Find out more about and AED from the Arrhythmia Alliance.

Angina and heart attacks

Angina is a syndrome (a collection of symptoms caused by an underlying health condition) caused by the supply of oxygen-rich blood to the heart becoming restricted.

People with angina can experience similar symptoms to a heart attack, but they usually happen during exercise and pass within a few minutes.

However, occasionally, people with angina can have a heart attack. It's important to recognise the difference between the symptoms of angina and those of a heart attack. The best way to do this is to remember that the symptoms of angina can be controlled with medicine, but symptoms of a heart attack cannot.

If you have angina, you may have been prescribed medicine (glyceryl trinitrate) that improves your symptoms within 5 minutes. If the first dose does not work, a second dose can be taken after 5 minutes, and a third dose after a further 5 minutes.

If the pain persists, despite taking 3 doses of glyceryl trinitrate over 15 minutes, call 999 and ask for an ambulance.

Page last reviewed: 28 November 2019
Next review due: 28 November 2022

Heart attacks are caused by the blood supply to the heart being suddenly interrupted. Without this supply, heart muscles may be damaged and begin to die.

Without treatment, the heart muscles will experience irreversible damage.

If a large portion of the heart is damaged in this way, the heart stops beating (known as a cardiac arrest), resulting in death.

Coronary heart disease

Coronary heart disease (CHD) is the leading cause of heart attacks. CHD is a condition in which the coronary arteries (the major blood vessels that supply the heart with blood) become clogged with deposits of cholesterol. These deposits are called plaques.

Before a heart attack, one of the plaques ruptures (bursts), causing a blood clot to form at the site of the rupture. The clot may block the supply of blood to the heart, triggering a heart attack.

Your risk of developing CHD is increased by:

Find out more about the causes of CHD.

Less common causes

Some less common causes are described here.

Drug misuse

Using stimulants such as cocaine, amphetamines (speed) and methamphetamines (crystal meth) can cause coronary arteries to narrow, restricting blood supply and triggering a heart attack.

Heart attack from the use of cocaine is one of the most common causes of sudden death in young people.

Lack of oxygen in the blood (hypoxia)

If levels of oxygen in the blood decrease due to carbon monoxide poisoning or a loss of normal lung function, the heart will receive un-oxygenated blood.

This will result in the heart muscles being damaged, triggering a heart attack.

Page last reviewed: 28 November 2019
Next review due: 28 November 2022

If a heart attack is suspected, you should be admitted to hospital immediately. You will usually be admitted to an acute cardiac care unit (ACCU), or directly to the cardiac catheterisation unit, to confirm the diagnosis and begin treatment.


An electrocardiogram (ECG) is an important test in suspected heart attacks. It should be done within 10 minutes of being admitted to hospital.

An ECG measures the electrical activity of your heart. Every time your heart beats, it produces tiny electrical impulses. An ECG machine records these signals onto paper, allowing your doctor to see how well your heart is functioning.

An ECG is painless and takes about 5 minutes to do. During the test, flat metal discs (electrodes) are attached to your arms, legs and chest. Wires from the electrodes are connected to the ECG machine, which records the electrical impulses.

An ECG is important because:

  • it helps confirm the diagnosis of a heart attack
  • it helps determine what type of heart attack you have had, which will help determine the most effective treatment

Types of heart attack

Heart attacks can be classified by a measurement from an ECG known as the ST segment. This corresponds to the area of damage inflicted on the heart.

Acute coronary syndrome

A heart attack is a form of acute coronary syndrome (ACS), where there is a significant blockage in the coronary arteries.

The 3 main types of ACS include:

  • ST segment elevation myocardial infarction (STEMI)
  • non-ST segment elevation myocardial infarction (NSTEMI)
  • unstable angina

ST segment elevation myocardial infarction (STEMI)

An STEMI is the most serious type of heart attack where there is a long interruption to the blood supply. This is caused by a total blockage of the coronary artery, which can cause extensive damage to a large area of the heart. An STEMI is what most people think of when they hear the term "heart attack".

Non-ST segment elevation myocardial infarction (NSTEMI)

An NSTEMI can be less serious than an STEMI because the supply of blood to the heart may be only partially, rather than completely, blocked. As a result, a smaller section of the heart may be damaged. However, an NSTEMI is still regarded as a serious medical emergency. Without treatment, it can progress to serious heart damage or STEMI.

Unstable angina

Unstable angina is the least serious type of ACS. However, like NSTEMI, it is still a medical emergency as it can also progress to serious heart damage or STEMI. In unstable angina, the blood supply to the heart is still seriously restricted, but there is no permanent damage, so the heart muscle is preserved.

Other tests

Other tests can be used to assess the state of your heart and check for related complications. However, because heart attacks are medical emergencies, some of these tests are usually done after your initial treatment has begun and your condition has been stabilised.

Blood tests

Damage to your heart from a heart attack causes certain proteins to slowly leak into your blood. Enzymes are special proteins that help regulate chemical reactions that happen in your body.

If doctors suspect you have had a suspected heart attack, a sample of your blood will be taken so it can be tested for these heart proteins (known as cardiac markers).

The most common protein measurement is called cardiac troponin. Your troponin level will be measured through a series of blood tests done over the course of a few days.

This will allow damage to your heart to be assessed, and also help determine how well you are responding to treatment.

Chest X-ray

A chest X-ray can be useful if diagnosis of a heart attack is uncertain and there are other possible causes of your symptoms, such as a pocket of air trapped between the layers of your lungs (pneumothorax).

A chest X-ray can also be used to check whether complications have happened because of the heart attack, such as a build-up of fluid inside your lungs (pulmonary oedema).


An echocardiogram is a type of scan that uses sound waves to build a picture of the inside of your heart.

This can be useful to identify exactly which areas of the heart have been damaged and how this damage has affected your heart's function.

Coronary angiography

Coronary angiography can help determine whether there is a blockage or narrowing in the coronary arteries and, if so, to locate the exact place of the blockage or narrowing.

The test involves inserting a thin tube (catheter), into one of the blood vessels in your groin or arm. The catheter is guided into your coronary arteries using X-rays.

A special fluid, called a contrast agent, is pumped through the catheter. This fluid can be seen on X-rays and studying how it flows around and through your heart can help locate the site of any blockage or narrowing. This helps a doctor who specialises in heart conditions (cardiologist) decide the best treatment for you.

Find out more about treating a heart attack.

Page last reviewed: 28 November 2019
Next review due: 28 November 2022

The treatment options for a heart attack depend on whether you've had an ST segment elevation myocardial infarction (STEMI), or another type of heart attack.

An ST segment elevation myocardial infarction (STEMI) is the most serious form of heart attack and requires emergency assessment and treatment. It's important you're treated quickly, to minimise damage to your heart after an STEMI.

If you have symptoms of a heart attack and an electrocardiogram (ECG) shows you have an STEMI, you'll be assessed for treatment to unblock your coronary arteries.

The treatment used will depend on when your symptoms started and how soon you can access treatment.

  • If your symptoms started within the past 12 hours – you'll usually be offered primary percutaneous coronary intervention (PCI).
  • If your symptoms started within the past 12 hours but you cannot access PCI quickly – you'll be offered medicine to break down blood clots.
  • If your symptoms started more than 12 hours ago – you may be offered a different procedure, especially if your symptoms have improved. The best course of treatment will be decided after an angiogram and may include medicine, PCI or bypass surgery.

Primary percutaneous coronary intervention (PCI)

Primary percutaneous coronary intervention (PCI) is the term for emergency treatment of an STEMI. It's a procedure to widen the coronary artery (coronary angioplasty).

Coronary angiography is done first, to assess your suitability for PCI.

You may also be given blood-thinning medicines to prevent further clots from forming, such as low-dose aspirin.

You may need to continue taking medicines for some time after PCI.

Coronary angioplasty

Coronary angioplasty is a potentially complex procedure that requires specialist staff and equipment, and not all hospitals have the facilities.

This means you'll need to be taken urgently, by ambulance, to one of the specialist centres (Heart Attack Centres) that now serve most of the UK's regions.

During coronary angioplasty, a tiny tube with a sausage-shape balloon at the end (a balloon catheter) is put into a large artery in your groin or arm. The catheter is passed through your blood vessels and up to your heart, over a fine guidewire, using X-rays to guide it.

Once the catheter is in the narrowed section of your coronary artery, the balloon is inflated to open it. Flexible metal mesh (a stent) is usually inserted into the artery to help keep it open afterwards.

Medicine to break down blood clots

Medicines used to break down blood clots, known as thrombolytics or fibrinolytics, are usually given by injection.

Thrombolytics, or fibrinolytics, target and destroy a substance called fibrin. Fibrin is a tough protein that makes up blood clots by acting like a sort of fibre mesh that hardens around the blood.

You may also be given a medicine called a glycoprotein llb/llla inhibitor if you have an increased risk of experiencing another heart attack in the future.

Glycoprotein IIb/IIIa inhibitors do not break up blood clots, but they prevent blood clots from getting bigger. They're an effective method of stopping your symptoms getting worse.

Coronary artery bypass graft

A coronary angioplasty may not be technically possible if the anatomy of your arteries is different from normal. This may be the case if there are too many narrow sections in your arteries or if there are lots of branches coming off your arteries that are also blocked.

In such circumstances, an alternative operation, known as a coronary artery bypass graft (CABG), may be considered.

A CABG involves taking a blood vessel from another part of your body (usually your chest, leg or arm) and attaching it to your coronary artery above and below the narrowed area or blockage. This new blood vessel is known as a graft.

The graft diverts blood around narrowed or clogged parts of your major arteries to improve blood flow and oxygen supply to your heart.

Treating non-ST segment elevation myocardial infarction (NSTEMI) and unstable angina

If an ECG shows you have an NSTEMI or unstable angina (the "less serious" types of heart attack), blood-thinning medicine, including aspirin and other medicines, is usually recommended.

In some cases, further treatment with coronary angioplasty or coronary artery bypass graft (CABG) may be recommended in cases of NSTEMI or unstable angina, after initial treatment with these medicines.

Page last reviewed: 28 November 2019
Next review due: 28 November 2022

Recovering from a heart attack can take several months, and it's very important not to rush your rehabilitation.

During your recovery period, you'll receive help and support from a range of healthcare professionals, which may include:

  • nurses
  • physiotherapists
  • dietitians
  • pharmacists
  • exercise specialists

These healthcare professionals will support you physically and mentally to ensure your recovery is conducted safely and appropriately.

The recovery process usually happens in stages, starting in hospital, where your condition can be closely monitored and your individual needs for the future can be assessed.

After being discharged from hospital, you can continue your recovery at home.

The 2 most important aims of the recovery process are:

  • to gradually restore your physical fitness so you can resume normal activities (known as cardiac rehabilitation)
  • to reduce your risk of another heart attack

Cardiac rehabilitation

Your cardiac rehabilitation programme will begin when you're in hospital.

You should also have another session within 10 days of leaving hospital.

A member of the cardiac rehabilitation team will visit you in hospital and provide detailed information about:

  • your state of health and how the heart attack may have affected it
  • the type of treatment you received
  • what medicines you'll need when you leave hospital
  • what specific risk factors are thought to have contributed to your heart attack
  • what lifestyle changes you can make to address those risk factors

They can also answer any questions you have about financial support, welfare rights, housing and social care.


Once you return home, it's usually recommended that you rest and only do light activities, such as walking up and down the stairs a few times a day or taking a short walk.

Gradually increase the amount of activity you do each day over several weeks. How quickly you can do this will depend on the condition of your heart and your general health.

Your care team can provide more detailed advice about a plan to increase your activity levels.

Your rehabilitation programme should contain a range of different exercises, depending on your age and ability. 

Most of the exercises will be aerobic. These are designed to strengthen your heart, improve circulation and lower blood pressure.

Examples of aerobic exercises include riding an exercise bike, jogging on a treadmill and swimming.

Returning to work

Most people can return to work after having a heart attack, but how quickly will depend on your health, the state of your heart and the kind of work you do.

If your job involves light duties, such as working in an office, you may be able to return to work in 2 weeks.

However, if your job involves heavy manual tasks or your heart was extensively damaged, it may be several months before you can return to work.

Your care team will provide a more detailed prediction of how long it will be before you can return to work.


According to the British Heart Foundation, you're usually able to start having sex again once you feel well enough, usually about 4 to 6 weeks after having a heart attack.

Having sex will not put you at further risk of having another heart attack.

Following a heart attack, some men have erectile dysfunction, which may make having sex difficult. This is most commonly due to anxiety and the emotional stress associated with having a heart attack.

Less commonly, erectile dysfunction is a side effect of a heart medicine called beta blockers.

If you experience erectile dysfunction, speak to a GP. They may be able to recommend treatment. For example, you may be prescribed medicine such as sildenafil which stimulates the flow of blood to the penis and makes it easier to get an erection.

Find out more about treatments for erectile dysfunction.


If you drive a car or motorcycle and you have a heart attack, you do not have to inform the Driver and Vehicle Licensing Agency (DVLA).

Many people can now return to driving 1 week after a heart attack, as long you do not have any other condition or complication that would disqualify you from driving.

But in more severe cases, you may need to stop driving for 4 weeks.

Your doctor or rehabilitation team should advise how long you must wait before driving after your heart attack.

If you drive a large goods vehicle or passenger-carrying vehicle, you must inform the DVLA if you have a heart attack.

Your licence will be temporarily suspended, for a minimum of 6 weeks, until you have adequately recovered.

Your licence will be reissued if you can pass a basic health and fitness test and do not have any other condition that would disqualify you from driving.


Having a heart attack can be frightening and traumatic, and it's common to have feelings of anxiety afterwards.

For many people, the emotional stresses can cause them to feel depressed and tearful for a few weeks after returning home from hospital.

If feelings of depression persist, speak to a GP, as you may have a more serious form of depression.

It's important to seek advice as serious types of depression often do not get better without treatment.

Your emotional state could also have an adverse effect on your physical recovery.

Reducing your risk

Reducing your risk of having another heart attack involves making lifestyle changes and taking different medicines long term. See preventing heart attacks for more information.


There are currently 4 types of medicines widely used to reduce the risk of a heart attack:

  • angiotensin-converting enzyme (ACE) inhibitors
  • anti-platelets
  • beta blockers
  • statins

ACE inhibitors

ACE inhibitors are often used to lower blood pressure, as they block the actions of some of the hormones that help regulate blood pressure.

By stopping these hormones from working, the medicine helps to reduce the amount of water in your blood and also widens your arteries, both of which will reduce your blood pressure.

ACE inhibitors have been known to reduce the supply of blood to the kidneys, which can reduce their efficiency. This means blood and urine tests may be done before you start taking ACE inhibitors to make sure there are no pre-existing problems with your kidneys.

Annual blood and urine tests may be required if you continue to take ACE inhibitors.

The side effects of ACE inhibitors can include:

  • dizziness
  • tiredness or weakness
  • headaches
  • a persistent, dry cough

Most of these should pass within a few days, although some people continue to have a dry cough.

If ACE inhibitors are taken with other types of medicines, including over-the-counter medicines, they can cause unpredictable side effects.

Check with a GP or pharmacist before taking any other medicines if you are taking an ACE inhibitor.

It's usually recommended that you begin taking ACE inhibitors immediately after having a heart attack and, in most cases, continue taking them indefinitely.

Some people cannot take ACE inhibitors. If this is the case, a related medicine called an angiotensin receptor blocker (ARB) may be prescribed as an alternative.


Antiplatelets are medicines that help prevent blood clots. They work by reducing the "stickiness" of platelets, which are tiny particles in the blood that help it to clot.

It's usually recommended that you take low-dose aspirin, which has blood-thinning properties.

You're more likely to be given additional antiplatelet medicines, such as clopidogrel, prasugrel or ticagrelor, especially if you have had stent treatment.

These can also be used if you're allergic to aspirin.

Side effects of antiplateletes can include:

As with ACE inhibitors, treatment with antiplatelets usually begins immediately after a heart attack.

How long you will take an antiplatelet can be between 4 weeks and 12 months and depends on the type of heart attack you have had and the other treatment you have received.

It's usually recommended that you take low-dose aspirin indefinitely.

If you experience troublesome side effects from aspirin, you should contact a GP for advice.

Do not suddenly stop taking aspirin, as this could increase your risk of another heart attack.

You may occasionally also be prescribed another blood-thinning medicine called warfarin.

This usually only happens if you have remained in an irregular heart rhythm (atrial fibrillation) or sustained severe damage to your heart.

Excessive bleeding is the most serious side effect of warfarin.

Seek immediate medical attention and have an urgent blood test if you experience any of the following side effects:

You must also seek immediate medical attention if you:

Beta blockers

Beta blockers are a type of medicine used to protect the heart from further damage after a heart attack.

They help to relax the heart's muscles so the heart beats slower and blood pressure drops, both of which will reduce the strain on your heart.

It's usually recommended that you begin treatment with beta blockers as soon as your condition stabilises, and continue taking them indefinitely.

Common side effects of beta blockers include:

  • tiredness
  • cold hands and feet
  • a slow heartbeat
  • diarrhoea
  • feeling sick

Less common side effects include:

  • difficulty sleeping or nightmares
  • inability to obtain or maintain an erection (erectile dysfunction, or impotence)

Beta blockers can also interact with other medicines, causing possible adverse side effects.

Check with a GP or pharmacist before taking any other medicines, including over-the-counter medicine, in combination with beta blockers.


Statins are a type of medicine used to reduce blood cholesterol.

This helps to prevent further damage to your coronary arteries and should reduce the risk of another heart attack.

Statins block the effects of an enzyme in your liver called HMG-CoA reductase, which is used to make cholesterol.

Statins sometimes have mild side effects, including:

Occasionally, statins can cause muscle pain, weakness and tenderness.

Contact a GP if you experience these symptoms, as your dosage may need to be adjusted.

It's usually recommended that you take statins indefinitely.

Getting help

Everyone who experiences a heart attack will face different problems and challenges, and any guidance or advice you receive will be tailored to your needs.

There are many local and national cardiac support groups where you can meet people who have been through a similar experience.

The British Heart Foundation's heart helpline offers confidential information about your recovery and advice about how to keep your heart healthy.

Call the helpline on 0300 330 3311 from 9am to 5pm, Monday to Friday.

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Potential complications from a heart attack can vary widely, from mild to life threatening.

Some people experience a "minor" heart attack (although it can still be very serious) with no associated complications. This is also known as an uncomplicated heart attack.

Other people experience a major heart attack, which has a wide range of potential complications and may require extensive treatment.


An arrhythmia is an abnormal heartbeat and can include:

Arrhythmias can develop after a heart attack as a result of damage to the heart muscles. Damaged muscles disrupt electrical signals that control the heart.

Some arrhythmias, such as tachycardia, are mild and cause symptoms such as:

Other arrhythmias can be life threatening, including:

  • complete heart block, where electrical signals are unable to travel from one side of your heart to the other, so your heart cannot pump blood properly
  • ventricular arrhythmia, where the heart begins beating faster before going into a spasm and stops pumping completely; this is known as sudden cardiac arrest

These life-threatening types of arrhythmia can be a major cause of death during the 24 to 48 hours after a heart attack.

However, survival rates have improved significantly since the invention of the portable defibrillator – an external device that delivers an electric shock to the heart and "resets" it to the right rhythm.

Mild arrhythmias can usually be controlled with medicine such as beta-blockers.

More troublesome bradycardias that cause repeated and prolonged symptoms may need to be treated with a pacemaker. This is an electric device surgically implanted in the chest to help regulate the heartbeat.

Find out more about sudden cardiac arrest from the charity Sudden Cardiac Arrest UK.

Heart failure

Heart failure happens when your heart is unable to effectively pump blood around your body. It can develop after a heart attack if your heart muscle is extensively damaged. This usually happens in the left side of the heart (the left ventricle).

Symptoms of heart failure include:

  • breathlessness
  • tiredness (fatigue)
  • swelling in your arms and legs due to a build-up of fluid

Heart failure can be treated with a combination of medicines and, in some cases, surgery.

Find out more about treating heart failure.

Cardiogenic shock

Cardiogenic shock is similar to heart failure, but more serious. It develops when the heart muscle has been damaged so extensively it can no longer pump enough blood to maintain many of the body's functions.

Symptoms include:

  • mental confusion
  • cold hands and feet
  • a decreased need to pee or not peeing at all
  • rapid heartbeat and breathing
  • pale skin
  • difficulty breathing

A type of medicine called vasopressors (or inotropes) may be used. Vasopressors help squeeze (constrict) the blood vessels, which increases blood pressure and improves blood circulation.

Once the initial symptoms of cardiogenic shock have been stabilised, surgery may be required to improve the functioning of the heart. This may include percutaneous coronary intervention (PCI), alongside the insertion of a small pump, known as an intra-aortic balloon pump. This can help improve the flow of blood from the heart.

Another option is a coronary artery bypass graft (where a blood vessel from another part of your body is used to bypass any blockage).

Heart rupture

A heart rupture is an extremely serious but relatively uncommon complication of a heart attack where the heart's muscles, walls or valves split apart (rupture).

It can happen if the heart is significantly damaged during a heart attack and usually happens 1 to 5 days afterwards.

Symptoms are the same as those of cardiogenic shock. Open heart surgery is usually required to repair the damage.

The outlook for people who have a heart rupture is poor; it's estimated that 1 in 2 people die within 5 days of the rupture occurring.

Page last reviewed: 28 November 2019
Next review due: 28 November 2022

Making lifestyle changes is the most effective way to prevent having a heart attack (or having another heart attack).

There are 3 main steps you can take to help prevent a heart attack (as well as stroke):

  • eat a healthy, balanced diet
  • do not smoke
  • try to keep your blood pressure at a healthy level

A healthy diet

Eating an unhealthy diet that is high in fat will make hardening of the arteries (atherosclerosis) worse and increase your risk of a heart attack.

Continuing to eat high-fat foods will cause more fatty plaques to build up in your arteries. This is because fatty foods contain an unhealthy type of cholesterol.

There are 2 main types of cholesterol:

  • low-density lipoprotein (LDL) – this is mostly made up of fat plus a small amount of protein; this type of cholesterol can block your arteries, so it is often known as "bad cholesterol"
  • high-density lipoprotein (HDL) – this is mostly made up of protein plus a small amount of fat; this type of cholesterol can reduce deposits in your arteries, so is often known as "good cholesterol"

There are also 2 types of fat – saturated and unsaturated. Avoid foods containing high levels of saturated fat, as they increase levels of LDL cholesterol in your blood.

Foods high in saturated fat include:

  • pies
  • fried foods
  • sausages and fatty cuts of meat
  • butter
  • ghee (a type of butter often used in Indian cooking)
  • lard
  • cream
  • hard cheese
  • cakes and biscuits
  • foods that contain coconut or palm oil

You should aim to follow a Mediterranean-style diet. This means eating more bread, fruit, vegetables and fish, and less meat.

Replace butter and cheese with products based on vegetable and plant oil, such as olive oil.

Oily fish, such as herring, sardines and salmon, can form part of a Mediterranean-style diet, but there's no need to eat this type of fish specifically to try to prevent another heart attack.

Also, taking omega-3 fatty acid supplements, or eating foods fortified with omega-3 fatty acids, has not been found to help prevent another heart attack.

Never take a food supplement without first consulting a GP. Some supplements, such as beta-carotene, are potentially harmful.

Find out more about changing your diet after a heart attack.


Smoking is a major risk factor for heart attack because it causes atherosclerosis and raises blood pressure.

A GP can refer you to a local NHS Stop Smoking Service, which will provide support and advice about the best ways to quit.

You can also call the NHS Smokefree Helpline on 0300 123 1044 (England only, from Monday to Friday 9am to 8pm, and Saturday and Sunday 11am to 4pm). Specially trained helpline staff offer free expert advice and encouragement.

If you are committed to quitting but do not want to be referred to a stop smoking service, a GP should be able to prescribe treatment to help with withdrawal symptoms you may experience.

Find out about self-help tips to stop smoking.

High blood pressure

Persistent high blood pressure (hypertension) can put extra strain on your arteries and heart, increasing your risk of a heart attack.

High blood pressure can often be reduced by eating a healthy diet, moderating your alcohol intake, maintaining a healthy weight and doing regular exercise.

Diet and high blood pressure

The advice on eating a healthy, balanced diet also applies if you have high blood pressure. In addition, cut down on the amount of salt in your food.

Salt raises blood pressure. The more salt you eat, the higher your blood pressure. You should aim to eat less than 6g of salt a day (2.4g sodium) – that's around 1 teaspoonful.

Find out how to cut down on salt.

Eating a low-fat diet that includes lots of fibre – such as wholegrain rice, bread, pasta and plenty of fruit and vegetables – has been proven to help lower blood pressure. Fruit and vegetables also contain vital vitamins and minerals and help keep your body healthy.

You should aim to eat 5 portions of fruit and vegetables every day.

Find out more about getting your 5 A Day.


If you drink alcohol, do not exceed the recommended limits:

  • men and women are advised not to regularly drink more than 14 units of alcohol a week
  • spread your drinking over 3 or more days if you regularly drink as much as 14 units a week

14 units is equivalent to 6 pints of average-strength beer, or 10 small glasses of low-strength wine.

Find out more about alcohol units.

Regularly exceeding the recommended alcohol limits raises your blood pressure and cholesterol level, increasing your risk of a heart attack.

Avoid binge drinking, which is drinking lots of alcohol in a short space of time or drinking to get drunk.

Binge drinking can cause a sudden and large rise in your blood pressure, which could be potentially dangerous.

Research has found people who have had a heart attack and continue to binge drink are twice as likely to die from a serious health condition, such as another heart attack or stroke, compared with people who moderate their drinking after having a heart attack.

Find tips for cutting down on alcohol.

Contact your GP if you find it difficult to moderate your drinking. Counselling services and medicines can help you reduce your alcohol intake.

Find out more about alcohol support.


Being overweight forces your heart to work harder to pump blood around your body, which can raise your blood pressure. Use the BMI healthy weight calculator to find out if you are a healthy weight for your height.

If you do need to lose weight, remember that losing just a few kilos will make a positive difference to your blood pressure and health.

Find out more about how to start losing weight.


Being active and doing regular exercise will lower your blood pressure by keeping your heart and blood vessels in good condition. Regular exercise can also help you lose weight, which will help to lower your blood pressure.

Low-impact activities such as walking, swimming and cycling are recommended. More strenuous activities, such as playing football and squash, may not be suitable for you. Check with the doctor in charge of your care.

Find out more about the benefits of walkingswimming for fitness and how to start cycling.

Page last reviewed: 28 November 2019
Next review due: 28 November 2022