Atrial fibrillation

Expert reviewed by Dr Matthew Wright, Consultant Cardiologist and Electrophysiologist
Next review due June 2020

Atrial fibrillation (AF) is a type of abnormal heartbeat (arrhythmia) in which your heartbeat is irregular, and often, too fast. It’s the most common type of arrhythmia – more than a million people in the UK have it. You’re more likely to get it as you get older, and more men than women get it.

Juliette, who has atrial fibrillation, says her story started when: "I told my GP that I sometimes feel a butterfly sensation in my chest." See our personal experience section to find out more about Juliette's story.

Older man carving at a workbench

What happens in atrial fibrillation?

Your heartbeat is controlled by electrical signals (impulses) that travel through your heart to make it contract.

Atrial fibrillation happens when faulty electrical signals in the upper chambers of your heart, called atria, become disorganised. This stops your atria contracting regularly and leads to the lower chambers (ventricles) contracting irregularly and so puts your heart out of rhythm. This can also make your heart beat too fast.

Watch our animation to see how your heart beats normally and what happens in atrial fibrillation.

There are different types of atrial fibrillation.

  • Paroxysmal atrial fibrillation is when your heart suddenly begins to beat in a disorganised way, and then returns to normal. This can happen for anything from half a minute to a week but it usually lasts less than a couple of days. It will usually keep coming back though.
  • Persistent atrial fibrillation is when your heart rhythm is abnormal for more than a week. This may get better with treatment.
  • Permanent atrial fibrillation is when your abnormal heart rhythm has gone on for longer than a year. And it hasn’t got better with a treatment called cardioversion (see below).

You might only get short, and only very occasional attacks of atrial fibrillation at first. But it can often steadily get worse to the point where it gets longer and more frequent, before becoming permanent.

Symptoms of atrial fibrillation

You might not get any symptoms of atrial fibrillation; or they may only be mild and not cause you any problems. So you might only find out you have it from having medical tests for something else. But if you have persistent or permanent atrial fibrillation, you could have symptoms most of the time, which include:

  • palpitations (a thumping in your chest)
  • finding it difficult to exercise, or not being able to exercise as well as normal
  • shortness of breath
  • tiredness
  • feeling dizzy or light-headed, or actually blacking out
  • going to the toilet more than usual (to wee)

If you have any of these symptoms, go and see your GP. If your symptoms come on suddenly, and you have chest pain or feel out of breath, go to the accident and emergency department of your nearest hospital.

Diagnosis of atrial fibrillation

You might not be aware that you have atrial fibrillation and it may only be discovered by chance in tests you have for another reason. But if you get any symptoms or have any concerns about your heart rhythm, go and see your GP. Our Cardiology Clinical Adviser, Dr Yassir Javaid, explains why in our video: When should you see a doctor about your heart?

Your GP will ask about your symptoms and examine you. They’ll take your pulse, check your blood pressure, and listen to your heartbeat. Your GP will also ask you about your medical history. If you’ve noticed anything that sets off your symptoms, let them know.

You’ll need to have a test called an electrocardiogram (ECG). An ECG records the electrical activity in your heart to see how well it’s working. You might need to wear a 24-hour heart monitor, which is called ambulatory ECG. This records the electrical activity of your heart while you go about your usual activities over 24 hours (or longer if necessary).

Your GP may give you (or refer you for) other tests, such as a transthoracic echocardiogram. This uses ultrasound to produce a clear image of your heart muscles and valves to see how well it's working. Other tests might include the following.

  • Blood tests. These will check for substances that may be causing atrial fibrillation or other conditions that may be causing your symptoms.
  • An exercise ECG (cardiac stress test). This is when you have an ECG while you exercise to see how your heart works under pressure. It may trigger abnormal heart rhythms, but you're in the best place for this to happen as you'll be surrounded by a medical team.
  • Chest X-ray. This will enable your doctor to look for any changes in your heart or lungs that might be causing the problem.

Treatment of atrial fibrillation

Atrial fibrillation treatments will be tailored to you and will depend on your symptoms, the type of atrial fibrillation you have and what’s causing it. Your GP will refer you to see a cardiologist for treatment – a doctor who specialises in identifying and treating heart conditions.

The main aim of treatment is to prevent complications, such as a stroke, and treat the symptoms of atrial fibrillation. Some treatments are used to stop your heart beating in a disorganised way or to control the speed at which it beats. Your doctor will talk through your treatment options with you.


Your doctor may prescribe you one or more medicines to help manage your symptoms. You may need to take these for several years. Each year (sometimes more often), your doctor will review whether you need to stay on your medicines.

Medicines for atrial fibrillation include the following.

  • Medicines to control your heart rate. These will control how fast your heart beats and include beta-blockers, calcium-channel blockers and digoxin.
  • Medicines to control your heart rhythm. Usually you’ll have cardioversion to do this (see below). But if cardioversion isn’t an option for you, you can have antiarrhythmic medicines, such as a beta-blocker, or a medicine called amiodarone or flecainide. 
  • Medicines to reduce blood clotting. If you have atrial fibrillation, it’s more likely that your blood will clot, which may in turn, increase your risk of having a stroke. Your doctor may prescribe you a medicine called an anticoagulant, which will thin your blood and reduce your risk. Examples include warfarin, apixaban, dabigatran, edoxaban and rivaroxaban.

Hospital treatment

If your symptoms are more serious or medicines haven’t controlled atrial fibrillation, you may need to have a procedure in hospital. Options include the following.


Cardioversion is a procedure to help return your heart’s rhythm to normal using a controlled electric shock to your chest. You can read all about what happens in our separate topic, Cardioversion.

Your doctor may offer you cardioversion straightaway if your atrial fibrillation started less than 48 hours ago and medicines haven’t helped, or you’re very unwell.

If your symptoms have lasted more than 48 hours and your cardiologist thinks cardioversion will help, they’ll prescribe you anticoagulant medicines (see above) first. You’ll need to take these for at least three weeks before and four weeks after your cardioversion. Or you can have a transoesophageal echocardiogram instead, to check if you have any blood clots in your heart.

Cardioversion is less likely to work if you’ve had an arrhythmia for a long time. And it might not be a good option for you if your atrial fibrillation comes and goes – your cardiologist will talk you through your best options.

Catheter ablation

Catheter ablation is a procedure to destroy any tissue in your heart that’s sending out irregular electrical signals and causing atrial fibrillation. In this procedure, your doctor will pass a small tube called an electrode catheter into the vein in your groin. They’ll pass it up to your heart and destroy any tissue that's disrupting or causing abnormal electrical signals.

Surgical ablation is another option – this is open heart surgery. But you’ll usually only have this if you’re having surgery for other reasons, such as bypass or heart valve surgery.

At least half of patients with atrial fibrillation who are treated with catheter ablation find that it solves the problem. It can work really well if you only occasionally get atrial fibrillation. It doesn’t always work first time though – about one in every four patients have to have the procedure repeated.

Pace and ablate

This is another type of ablation that works for some people – another name for it is AV (atrioventricular) node ablation. This destroys the part of your heart tissue that carries electric signals from the upper to lower chambers of your heart (the AV node). You’ll need to have a pacemaker fitted to take over the role of controlling your heart beat. A pacemaker is a small device that monitors your heartbeat and sends electrical signals to stimulate your heart to beat at a specific rate. A cardiologist will put the pacemaker under the skin on your chest, or under the muscle, just under your collarbone. You’ll usually have this fitted six weeks before your pace and ablate procedure to check it’s working well and there aren’t any issues with it.

 Worried about your heart health?

Get a picture of your current health and potential future health risks with one of our health assessments. Find out more today. Find out more about health assessments >

 Worried about your heart health?

Personal experience: Juliette’s story

Sometimes hearing from someone who has experienced a condition can help you to understand it better. Here, Juliette shares her personal experience of living with atrial fibrillation and how it has affected her.

“I told my GP that I sometimes feel a butterfly sensation in my chest. He fitted me with a 24-hour heart monitor, which picked up abnormal heart beats, so he referred me to a cardiologist.

“Before seeing the cardiologist, I wore a heart monitor for seven days. The cardiologist confirmed that I had paroxysmal atrial fibrillation and put me on beta blockers to slow my heart rate. He also sent me for a contrast echocardiogram to rule out any other heart conditions that might be causing the atrial fibrillation, which thankfully there weren’t.

“After experiencing side effects from taking medications, I was referred for a catheter ablation. I have an appointment coming up to find out if that has been successful (it’s common to need more than one of these to work).

“The condition itself hasn’t been too problematic, but the biggest strain has been on my mental health. Since my diagnosis, I’ve had the worry that this may have been caused by something more sinister, which thankfully it hasn’t. There’s been the side effects of the drugs, the apprehension of the ablation procedure (which wasn’t too bad after all) and now of course the anticipation of whether it has worked or not. I’m otherwise very healthy. I don’t smoke, am a healthy weight, am active and don’t drink too much (none at all for the last year) or have other underlying health problems.

“That said, I’ve had a shock. I feel hard done by that I have this when I’m otherwise healthy and only 42, yet it’s more common in older men ! But as a result now have quite a different outlook on life, which I am grateful for. I’ll soon be running a local (hilly) 10km for the British Heart Foundation, whose leaflets and website were very comforting in those moments in the middle of the night when my heart was thumping away irregularly and I was anxious about the condition and treatment.”

Causes of atrial fibrillation

Atrial fibrillation is often caused by other health conditions. In fact, about nine out of every 10 people with atrial fibrillation have another health condition that’s causing their heart rhythm problems. These include:

You might also get atrial fibrillation if you’re very unwell, or you’ve recently had heart surgery. And your risk of getting atrial fibrillation increases as you get older, particularly if you’re over 65.

You may also find that some things can trigger atrial fibrillation, such as:

  • having too much caffeine
  • drinking too much alcohol
  • using illegal drugs, such as cocaine

Complications of atrial fibrillation

If you have atrial fibrillation, you’re about five times more likely to have a stroke than someone who doesn’t have the condition. Atrial fibrillation can cause stroke because blood doesn’t flow properly through your heart and the rest of your body. Clots can form in the chambers of your heart. If the clot breaks off, it could travel through your body and block a blood vessel in your brain and cause a stroke.

If your doctor thinks you’re at a higher risk of a stroke, they may prescribe you an anticoagulant medicine, such as warfarin. This will reduce the chance of a blood clot forming.

If you have atrial fibrillation for a long time, you’re also at increased risk of heart failure as your heart is unable to pump blood around your body well. See our topic on Heart failure for more information about how to manage this risk.

Your doctor might ask you some questions to see if you’re at risk of a stroke or heart failure. They’ll then formulate a plan with you to manage this risk.

Frequently asked questions

  • No, there are lots of other reasons why you may have palpitations, and most aren’t serious. Sometimes your heart might feel like its skipped a beat, or there’s an extra beat, for example. An extra beat is called an ectopic beat and is really common. They aren’t usually anything to worry about and you don't usually need any treatment.

    If you have palpitations, you’ll become aware of your heart racing, beating in a strange pattern or thumping in your chest. Most people get palpitations at some time – including people without atrial fibrillation. While they can be unpleasant and distressing, they may be harmless and go away on their own.

    Palpitations can be triggered by:

    If your palpitations don't seem to be triggered by anything, or you also have other symptoms such as dizziness or chest pain, see your GP.

    You can watch our expert, Dr Asif Qasim, Consultant Cardiologist at Bupa Cromwell Hospital, talk about arrhythmias, palpitations and heart rhythm problems in our video.

  • Yes, it will probably be safe for you to exercise, and it’s important for your health.

    Generally speaking, exercise is good for your heart and helps you to stay healthy. Our Cardiology Clinical Adviser, Dr Yassir Javaid, explains why in our video: What can you do to improve your heart health?

    Once your atrial fibrillation is under control, your doctor may recommend that it’s safe for you to start exercising again. You might find that you get tired easily with exercise at first, but this should improve as you get fitter. Check out our information dedicated to helping people get started when it comes to exercise for more tips and advice. Always stop if you feel sick, dizzy, get palpitations or other symptoms and talk through what happened with your doctor before you start again.

  • All medicines can cause side-effects. Discuss these with your doctor or pharmacist before you start any treatment, so you can weigh up the risks and benefits of taking the medicine.

    Medicines for atrial fibrillation can cause some side-effects. We explain some of the more common ones below. Make sure you read the patient information leaflet that comes with your medicine to understand what side-effects your medicine can cause. Talk to your pharmacist or doctor about these if you’re concerned.

    • Although anticoagulants, such as warfarin, work well to prevent blood clots, they may thin your blood too much, which can increase your risk of bleeding. To make sure your risk of bleeding isn’t too high, you may have regular tests to see how quickly your blood clots. Or your doctor might ask you to do tests yourself at home. Your treatment can then be adjusted if need be.
    • The antiarrhythmic medicine, amiodarone, can sometimes cause problems with your thyroid gland, lungs and liver, and make your skin very sensitive to sunlight. If you’re prescribed amiodarone, you’ll have regular check-ups and will need to wear a sunscreen and cover up in the sun more than usual.
    • Beta-blockers may make you feel tired, cause your hands and feet to feel cold and make you dream more, possibly disturbing your sleep.
    • Calcium-channel blockers can cause changes in blood pressure, headaches and swollen ankles.

    The benefits of your medicine should largely outweigh the risks and problems caused by side-effects. If you have any concerns about side-effects, talk to your pharmacist or doctor.

  • Atrial fibrillation happens when faulty electrical signals in the upper chambers of your heart, called atria, become disorganised, and your heart beats irregularly. Other types of arrhythmia are caused by different faulty electrical signals, or in different areas of your heart.

    More information

    Other types of arrhythmia are caused by problems in other areas of the heart.

    • Supraventricular tachycardia (SVT) happens when there’s a problem above your ventricles (the lower chambers of your heart). Often, there’s an extra pathway (or pathways) in your heart between your atria (the top chambers of your heart) and your ventricles.
    • Ventricular tachycardia happens when electrical signals fire too quickly in your ventricles, which results in a very fast heartbeat. This doesn’t give your ventricles enough time to fill with blood before your heart contracts so not enough blood is pumped to the rest of the body.
    • Ventricular fibrillation happens when electrical signals fire off in different areas of your ventricles at the same time. It’s an extremely fast, life-threatening heart rhythm that results in you heart being unable to pump blood around your body.
    • Heart block happens when the electric signals travelling from your atria to your ventricles are slowed down or blocked.
    • Tachy-brady syndrome is a type of what’s called sick sinus syndrome. This happens when the node in your heart which first starts an electric signal (your sinoatrial node) doesn’t work properly.

About our health information

At Bupa we produce a wealth of free health information for you and your family. This is because we believe that trustworthy information is essential in helping you make better decisions about your health and wellbeing.

Our information is guided by the principles of The Information Standard and complies with the HONcode standard for trustworthy health information. We are also a proud member of the Patient Information Forum.

PIF member logo  This website is certified by Health On the Net Foundation. Click to verify.

Learn more about our editorial team and principles >

Related information

    • Atrial fibrillation. National Institute for Health and Care Excellence (NICE)., 9 July 2015
    • Map of medicine. Atrial fibrillation. International view. London: Map of medicine; 2016 (issue 3)
    • Dealing with abnormal heart rhythms. British Heart Foundation., published 1 December 2015
    • Atrial fibrillation. NICE Clinical Knowledge Summaries., last revised 18 June 2014
    • Conduction system of the heart. Medscape., updated 28 June 2016
    • Atrial fibrillation. Medscape., updated 10 April 2017
    • Arrhythmias. Oxford handbook of cardiology (online). Oxford Medicine Online., published May 2012
    • Personal communication, Dr Matthew Wright, Consultant Cardiologist and Electrophysiologist, 28 June 2017
    • Electrocardiography. Medscape., updated 17 April 2017
    • Cardiac tests. Medscape., updated 18 December 2016
    • Arrhythmias. NICE British National Formulary., reviewed 28 April 2017
    • Chronic atrial fibrillation. BMJ Best Practice., last updated 14 October 2016
    • Atrial fibrillation and heart valve disease: self-monitoring coagulation status using point‑of‑care coagulometers (the CoaguChek XS system and the INRatio2 PT/INR monitor). National Institute for Health and Care Excellence (NICE)., September 2014
    • Edoxaban. NICE British National Formulary., reviewed 5 June 2017
    • Atrial fibrillation. British Heart Foundation., published 26 August 2015
    • Catheter ablation. Medscape., updated 6 July 2015
    • Palpitations. PatientPlus., last checked 24 November 2015
    • Palpitations. NICE Clinical Knowledge Summaries., last revised May 2015
    • Amiodarone hydrochloride. NICE British National Formulary., reviewed 28 April 2017
    • Beta-adrenoceptor blocking drugs. NICE British National Formulary., reviewed 28 April 2017
    • Calcium-channel blockers. NICE British National Formulary., reviewed 28 April 2017
    • Cardiovascular system anatomy. Medscape., updated 20 August 2014
    • Supraventricular tachycardia. PatientPlus., last checked 2 December 2016
    • Ventricular tachycardia. Medscape., updated 31 December 2015
    • Ventricular fibrillation. Medscape., updated 29 April 2014
    • Overview of dysrhythmias (cardiac). BMJ Best Practice., last updated 20 March 2017
    • Sick sinus syndrome. PatientPlus., last checked 16 April 2014
  • Reviewed by Rachael Mayfield-Blake, Freelance Health Editor, June 2017
    Expert reviewed by Dr Matthew Wright, Consultant Cardiologist and Electrophysiologist
    Next review due June 2020

Did our information help you?

We’d love to hear what you think. Our short survey takes just a few minutes to complete and helps us to keep improving our health information.