Atrial fibrillation (AF) and stroke

Atrial fibrillation (AF) is a heart condition that causes an irregular heartbeat and raises your risk of a serious stroke.

What do I need to know about atrial fibrillation (AF)?

  • Atrial fibrillation is a heart rhythm problem which raises your risk of a stroke.

  • AF makes you five times more likely to have a stroke. If you’re diagnosed with AF, you’ll have an individual stroke risk assessment to make sure you get the right treatment and advice for you.

  • Strokes due to AF tend to be more serious, with more damage to the brain and worse long-term effects. So if you have AF, you’ll be offered any treatment you need to reduce your risk of a stroke.

Your heart, AF and stroke

How can AF cause a stroke?

Normally, blood flows into the heart, and gets fully pumped out every time the heart beats. But in AF, blood can pool inside the heart. A clot can form in the blood and then travel up to the brain, causing a stroke.

What happens to the heartbeat in atrial fibrillation?

Your heart is a powerful pump. Its job is to keep the blood constantly moving around your body, bringing vital oxygen to your cells and organs.

The heart is designed to contract (beat) regularly, pumping blood around the body. Your heart contracts when specialised ‘pacemaker cells’ in the heart send out electrical impulses. The pacemaker cells set the rhythm of your heartbeat. In AF, the electrical impulses that set your heartbeat are disrupted. The heartbeat can become irregular, and may be extremely fast.

Your heart has four chambers:

  • Left and right atria.

  • Left and right ventricles.

Specialised cells send electrical impulses to set your heartbeat. These cells are known as the pacemaker, or sinoatrial node. They can adapt to your body’s oxygen needs, speeding up if you move around, or slowing down when you rest.

How is atrial fibrillation diagnosed?

Tests and checks to find out whether you have AF include:

  • An electrocardiogram (ECG) tests the electrical activity of your heart. It’s painless and usually takes less than 10 minutes. It may be done by your GP or in hospital. Because AF can come and go, you might be given a wearable device to track your heartbeat over 24 hours.

  • An echocardiogram is a type of ultrasound that checks the heart’s structure and function.

  • Blood tests for conditions such as overactive thyroid.

Who can get AF?

AF can happen to anyone, including people who are otherwise fit and well. It usually affects adults, and your risk goes up with age. It’s more common in men, and people with conditions such as heart disease, diabetes, obesity, overactive thyroid, and high blood pressure. It’s also more common in smokers.

How do I know I have it?

Atrial fibrillation often has no symptoms. Because of this, you might only find out you have AF during a routine medical check-up or after a stroke. AF sometimes has symptoms including palpitations (feeling as if your heart is fluttering, thumping or skipping a beat), fatigue, feeling breathless or having chest pain. If you are having symptoms or notice an abnormal pulse, contact your GP or stroke nurse. If you are having worrying symptoms such as chest pains, call 999.

Reducing your risk of stroke with AF

If you have AF, your doctor will discuss with you whether you need treatment to reduce your risk of stroke. The main treatment is a blood thinning medication called an anticoagulant. You may also be offered treatment to help your heart beat more effectively. This can include medication or surgical procedures to restore heart rhythm.

Assessing your risk

Doctors assess your stroke risk using a scoring system called CHA2DS2-VASc. This can help you and your doctor to decide on your treatment together. To see the CHA2DS2-VASc scale please download the Atrial fibrillation (AF) and stroke guide (PDF) and go to page 3.

Blood thinning medications to reduce your risk

Anticoagulant medications are the main treatment given to reduce your risk of stroke with atrial fibrillation. They reduce your risk of stroke by slowing down the clotting process, and making a clot less likely to form.

Anticoagulants: benefits and risks Benefits: anticoagulants help to protect your brain by reducing your chance of a stroke. If you have already had a stroke or transient ischaemic attack (TIA or mini-stroke), anticoagulants for AF help you reduce your risk of another stroke while you continue your recovery.

Risks: because anticoagulants reduce clotting, this can make you bleed more than usual if you have an injury. It can also cause bleeding inside your body, including the digestive system and brain.

To help you decide on the right treatment, your doctor will discuss the risks and benefits of medication with you. This includes your individual health, and your stroke risk score.

Because your stroke risk can change over time, you should be regularly reassessed, and your treatment will be monitored at least once a year. You may have regular tests while you are taking certain types of anticoagulant.

Help and support with anticoagulants

Types of anticoagulant

Anticoagulants have changed in recent years. You may have heard of warfarin, but there are several other options available which are more commonly used. The main types of anticoagulant are below (brand names may vary).

  • Apixaban.

  • Dabigatran.

  • Edoxaban.

  • Rivaroxaban.

  • Warfarin.

When you start a new long-term medication such as anticoagulants, you might need information and support. You’ll be monitored when you first start taking the medication, and your dose and the type of medication could be changed until doctors find what works best for you.

What else can I do to reduce my risk of stroke?

There are many things you can do to lower your chances of having a stroke. These include:

  • Managing any other medical conditions you have, for example high cholesterol or diabetes.

  • Having treatment for high blood pressure.

  • Stopping smoking.

  • Limiting the amount of alcohol you drink.

  • Following a healthy diet.

  • Exercising regularly.

Look for information about healthy lifestyle changes in our guide ‘How to reduce your risk of a stroke’ and visit

What else do I need to know?

Always read the patient information leaflet that comes with your medication, and check with the pharmacist how and when to take the pills.

  • If you feel unwell or have side-effects, don’t stop taking your medication, as this can put you at risk of a stroke. Contact your GP or pharmacist for advice. You may be able to try a different type of medication, or have a medication review. If you’re having stroke symptoms, or bleeding in your wee, poo or vomit, call 999.

  • Ask the GP or pharmacist about any other medications, including non-prescription treatments you are using such as herbal remedies.

  • Carry an alert card, available from your GP or pharmacist.

Types of atrial fibrillation

AF has three categories, which depend on how long the symptoms last.

  • Paroxysmal AF comes and goes, and episodes stop within seven days without treatment.

  • Persistent AF lasts more than seven days and need treatment.

  • Permanent or long-standing persistent AF means you have had continuous atrial fibrillation for a year or more.

What is ‘lone AF’?

You might hear your condition described as “lone” AF. This term is sometimes used when you don’t have any other risk factors or conditions causing your AF. However, this doesn’t affect your treatment options, which will depend on you and your individual risk of stroke.

Atrial flutter

Atrial flutter is a similar condition to AF, and you can have both at the same time. With atrial flutter, your upper heart chambers (atria) beat very fast, but regularly. Your heart may beat up to 150 times a minute and this can cause similar symptoms to AF, such as shortness of breath and fatigue. It is diagnosed in the same way as AF, and can also increase your risk of stroke.

Catheter ablation

If medication doesn’t work, catheter ablation can be used to remove the heart cells which are causing the irregular electrical impulses. This procedure uses thin wires guided through a vein to locate the abnormal electrical activity in the heart. The cells are then destroyed using high-frequency radio waves.

AF triggers

AF symptoms can be triggered by drinking alcohol. Some illegal drugs such as cocaine or amphetamines can trigger an episode of AF. Some people find that caffeine in drinks like coffee or soft drinks can give the feeling of a racing heart, but moderate amounts of caffeine don’t cause AF.

Treating an irregular heartbeat

On top of treatment to reduce your stroke risk, you may have treatments to improve your heart rate and rhythm control.

Heart rate control

If your heart beats too fast (over 100bpm resting heart rate) you may need medication to slow your heart rate. The main type used is beta blockers, but an alternative is calcium channel blockers. If you can’t use medication, you might be offered a heart pacemaker.

Heart rhythm control

If an irregular heart rhythm is causing symptoms, you may be offered electrical cardioversion treatment. This is a nonsurgical therapy. It uses a controlled electric shock to restore a normal rhythm.

Irregular heartbeat can also be treated with medications, including beta blockers and flecainide.

Find your heart rate

If you want to check your heart rate, you can try a manual pulse check or use a mobile device like a fitness tracker. But these can’t be relied on to diagnose AF, and you need medical checks to diagnose and monitor AF.

Manual pulse check

Wrist: while sitting down, press two fingers on the inside of the opposite wrist, next to the tendon under the thumb. You might have to try a few times to find your pulse.

Neck: gently press two fingers to the side of your Adam’s apple, just below the jaw. To find your heart rate, either:

  • Count your pulse for 60 seconds or

  • Count your pulse for 30 seconds and multiply by two.

Using mobile technology

Many mobile devices like phones and watches now have the ability to check body functions like heart rate, blood pressure and blood oxygen levels. Using your mobile device to measure your heart rate can be a good way of spotting early signs of any problems.

There are some devices on the market that can take very accurate readings which can be used by your doctors. However, most standard mobile devices and apps don’t give highly precise readings, and you will also need medical tests to get the full picture.

Understand your heart rate

  • Normal heart rate: your pulse should feel regular. Most people have a resting heart rate between 60 and 100 beats per minute (bpm).

  • Abnormal heart rate: your pulse may feel uneven, or skip a beat. Your resting heart rate could be over 120 bpm.

You can read more about Atrial fibrillation (AF) and stroke in the PDF below.

Information guide

Where to get help and information from the Stroke Association

Call us on 0303 3033 100,from a textphone 1800 0303 3033 100
Our Helpline offers information and support for anyone affected by stroke, including family, friends and carers.

Other sources of help and information

Arrhythmia Alliance
Phone: 01789 867 501
Supports people with all types of heart arrhythmias.

Atrial Fibrillation Association
Phone: 01789 867 502
Supports people with all AF, offering a range of leaflets, treatments and types of medication, plus details of AF specialists.

British Heart Foundation
Phone: 0300 330 3311
Provides information and support on heart issues including a nurse-led helpline.

Provides information about atrial fibrillation and the anticoagulant medications used to treat it.

NHS Medicine Service
Pharmacy-based support service (England only)
In England, you can join the New Medicines Service (NMS) by asking your local pharmacist. This gives you three appointments with your pharmacist in a private consultation room. The service helps you with getting started, and supports you with solving any problems.

Disclaimer: The Stroke Association provides the details of other organisations and apps for information only. Inclusion on My Stroke Guide does not constitute a recommendation or endorsement.