Cardiac arrest

Symptoms

What are the signs and symptoms of a cardiac arrest?

If someone is in cardiac arrest, they collapse suddenly and will be:

• unconscious
• unresponsive
• not breathing or not breathing normally – they may make gasping noises.

A cardiac arrest is an emergency that usually happens without warning.

Without immediate treatment, the person will die. Call 999 and start CPR if you see someone having a cardiac arrest.

Causes

What causes a cardiac arrest?

A cardiac arrest is when your heart has stopped beating and blood is not being pumped around your body.

It happens when your heart’s electrical system does not work properly and your heart starts beating too quickly, too slowly or irregularly. This is an abnormal heart rhythm, called an arrhythmia.

Not all abnormal heart rhythms are life-threatening, but some mean that the heart cannot pump blood around the body.

Abnormal heart rhythms that can lead to a cardiac arrest include:

• ventricular fibrillation (VF)
• ventricular tachycardia (VT)
• supraventricular tachycardia (SVT).

Can other conditions cause a cardiac arrest?

Some conditions can cause abnormal heart rhythms and in turn, a cardiac arrest if they're severe or left untreated:

• Cardiomyopathies – diseases of the heart muscle.
• Inherited heart conditions – affects the electrical system of the heart, such as Brugada syndrome.
• Congenital heart disease – a heart condition or defect you get before you’re born.
• Heart failure – when your heart cannot pump blood around your body as well as it should.
• Heart valve disease – when one or more of your heart valves do not work properly.
• Severe or untreated myocarditis – inflammation of the heart muscle.

Other causes of cardiac arrest include:

• a heart attack (often caused by coronary artery disease)
• losing a large amount of blood (severe haemorrhage)
• a sudden drop in oxygen levels (hypoxia)
• being electrocuted
• a drug overdose.

Treatments

How is a cardiac arrest treated?

Call 999 and start CPR immediately if you're with someone who's having a cardiac arrest. Follow instructions from the 999 operator until emergency services arrive and take over.

If someone is with you, ask them to go get a defibrillator. The defibrillator will give a controlled electric shock to try and get the heart beating normally again. You do not need training to use one, the machine will talk you through the steps.

Starting CPR immediately is important as it keeps blood and oxygen moving to the brain and around the body.

What are non-shockable rhythms?

Non-shockable rhythms are when the electrical activity in your heart does not respond to electrical shocks from a defibrillator. You will need to continue giving the person CPR.

Recovery

How do I recover from a cardiac arrest?

Immediate recovery

After a cardiac arrest, you’ll be looked after in a coronary care or intensive care unit. This is where people who need special monitoring go so a close eye can be kept on them. You may be kept asleep (an induced coma) to allow your body to recover.

Mid-term recovery

Doctors will want to work out what caused your cardiac arrest. They can then recommend medicine and treatment to reduce the risk of it happening again.

Treatments may include:

• an implantable cardioverter defibrillator (ICD).
• ablation.

They may also refer you to cardiac rehabilitation to help rebuild your confidence, fitness and strength levels.

Long-term recovery

The time it takes to recover depends on what caused your cardiac arrest and how long it took for your heart to beat on its own again after the arrest.

It could take several weeks, a few months or longer if you need more rehab for things like learning to walk and caring for yourself again.

However long it takes, your doctor will support you during this time. Talk to family and doctors about what will happen once you go home and practical matters, like driving and returning to work.

Are there long-term effects after a cardiac arrest?

A lack of oxygen to the brain during a cardiac arrest can sometimes have long-term effects on your brain. Effects can include:

• personality changes
• problems with memory
• feeling tired
• dizziness or balance issues
• problems with speech and language (aphasia and dysphasia)
• involuntary muscle movements (myoclonus)
• permanent brain injury.

Your doctor can help you get specialist support like speech and language therapists or an occupational therapist.

How will I feel after having a cardiac arrest?

It’s normal to have no memory of a cardiac arrest and you may feel low, angry, confused or a combination of lots of different emotions due to the shock of the experience. It can also be difficult for your family members who may have seen it happening.

Speak to your doctor if you’re concerned about how you’re feeling as they may be able to refer you to counselling. You can also refer yourself for talking therapies on the NHS.

Our emotional wellbeing webpages have information about topics such as anxiety and depression, caring for someone who's had a cardiac arrest and life after you’ve given someone CPR.

Reduce your risk

How can I reduce my risk of having a cardiac arrest?

Your doctor may suggest making lifestyle changes to reduce your risk of another cardiac arrest. This can include:

• eating a healthy diet
• quitting smoking
• cutting down on alcohol
• taking medicine and following treatments from your doctor
• being physically active.

You’re able to get an NHS Health Check for your risk of heart disease, kidney disease, stroke and other issues if you live in England. If you live elsewhere in the UK, contact your GP about getting checked for your risk of heart disease.

Get support

• Speak to our cardiac nurses by phone, callback, email or online chat on Heart Helpline (Monday to Friday, 9am to 5pm).
• Sign up to our Heart Matters magazine for online information packed with health and lifestyle information.
• Find more support from Sudden Cardiac Arrest UK, including meeting people who've had a cardiac arrest.
• Find emotional support.