Overview
Atrial fibrillation is a heart condition that causes an irregular and often abnormally fast heart rate.
A normal heart rate should be regular and between 60 and 100 beats a minute when you're resting.
You can measure your heart rate by checking your pulse in your wrist or neck.
Symptoms of atrial fibrillation
In atrial fibrillation, the heart rate is irregular and can sometimes be very fast. In some cases, it can be considerably higher than 100 beats a minute.
This can cause problems including dizziness, shortness of breath and tiredness.
You may be aware of noticeable heart palpitations, where your heart feels like it's pounding, fluttering or beating irregularly, often for a few seconds or, in some cases, a few minutes.
Sometimes atrial fibrillation does not cause any symptoms and a person who has it is completely unaware that their heart rate is irregular.
When to see a GP
See a GP or call 111 if:
- you have chest pain that comes and goes
- you have chest pain that goes away quickly but you're still worried
- you notice a sudden change in your heartbeat
- your heart rate is consistently lower than 60 or above 100 (particularly if you're experiencing other symptoms of atrial fibrillation, such as dizziness and shortness of breath)
- It's important to get medical advice to make sure it's nothing serious.
Call 999 if:
You have sudden chest pain that:
- spreads to your arms, back, neck or jaw
- makes your chest feel tight or heavy
- also started with shortness of breath, sweating and feeling or being sick
- lasts more than 15 minutes
You could be having a heart attack. Call 999 immediately as you need immediate treatment in hospital.
What causes atrial fibrillation?
When the heart beats normally, its muscular walls tighten and squeeze (contract) to force blood out and around the body.
They then relax so the heart can fill with blood again. This process is repeated every time the heart beats.
In atrial fibrillation, the heart's upper chambers (atria) contract randomly and sometimes so fast that the heart muscle cannot relax properly between contractions. This reduces the heart's efficiency and performance.
Atrial fibrillation happens when abnormal electrical impulses suddenly start firing in the atria.
These impulses override the heart's natural pacemaker, which can no longer control the rhythm of the heart. This causes you to have a highly irregular pulse rate.
The cause is not fully understood, but it tends to affect certain groups of people, such as older people and people living with long-term (chronic) conditions such as heart disease, high blood pressure or obesity.
It may be triggered by certain situations, such as drinking too much alcohol or smoking.
Atrial fibrillation can be defined in various ways, depending on the degree to which it affects you.
For example:
- paroxysmal atrial fibrillation – episodes come and go, and usually stop within 48 hours without any treatment
- persistent atrial fibrillation – each episode lasts for longer than 7 days (or less when it's treated)
- permanent atrial fibrillation – where it's present all the time
- long-standing atrial fibrillation – where you have had atrial fibrillation usually for over a year
Who's affected?
Atrial fibrillation is the most common heart rhythm disturbance, affecting around 1.4 million people in the UK.
It can affect adults of any age, but it's more common in older people.
More men than women have atrial fibrillation.
Atrial fibrillation is more likely to occur in people with other conditions, such as high blood pressure (hypertension), atherosclerosis or a heart valve problem.
Treating atrial fibrillation
Atrial fibrillation is not usually life threatening, but it can be uncomfortable and often requires treatment.
Treatment may involve:
- medicines to prevent a stroke (people with atrial fibrillation are more at risk of having a stroke)
- medicines to control the heart rate or rhythm
- cardioversion – where the heart is given a controlled electric shock to restore normal rhythm
- catheter ablation – where the area inside the heart that's causing the abnormal heart rhythm is destroyed using radiofrequency energy; afterwards you may then need to have a pacemaker fitted to help your heart beat regularly
Atrial flutter
Atrial flutter is less common than atrial fibrillation, but shares the same symptoms, causes and possible complications.
Around a third of people with atrial flutter also have atrial fibrillation.
Atrial flutter is similar to atrial fibrillation, but the rhythm in the atria is more organised and less chaotic than the abnormal patterns caused by atrial fibrillation.
Treatment for atrial flutter is also slightly different. Catheter ablation is considered to be the best treatment for atrial flutter, whereas medicine is often the first treatment used for atrial fibrillation.
Symptoms
Some people with atrial fibrillation, particularly older people, do not have any symptoms.
The irregularity in heart rhythm is often only discovered during routine tests or investigations for another condition.
Typically, a cardioversion (where the heart is given a controlled electric shock to restore normal rhythm) is carried out.
At this point, many people feel much better and realise they had not been feeling normal.
People often attribute tiredness and feeling lethargic to ageing, but once normal rhythm is restored, they realise these symptoms were caused by atrial fibrillation.
Heart palpitations
The most obvious symptom of atrial fibrillation is heart palpitations – where the heart feels like it's pounding, fluttering or beating irregularly, often for a few seconds or possibly a few minutes.
As well as an irregular heartbeat, your heart may also beat very fast (often considerably higher than 100 beats per minute).
You can work out your heart rate by checking the pulse in your neck or wrist.
Other symptoms you may experience if you have atrial fibrillation include:
- tiredness and being less able to exercise
- breathlessness
- feeling faint or lightheaded
- chest pain
The way the heart beats in atrial fibrillation reduces the heart's performance and efficiency.
This can lead to low blood pressure (hypotension) and heart failure.
See a GP or call 111 if:
- you have chest pain that comes and goes
- you have chest pain that goes away quickly but you're still worried
- you notice a sudden change in your heartbeat
- your heart rate is consistently lower than 60 or above 100 (particularly if you're experiencing other symptoms of atrial fibrillation, such as dizziness and shortness of breath)
It's important to get medical advice to make sure it's nothing serious.
Call 999 if:
You have sudden chest pain that:
- spreads to your arms, back, neck or jaw
- makes your chest feel tight or heavy
- also started with shortness of breath, sweating and feeling or being sick
- lasts more than 15 minutes
You could be having a heart attack. Call 999 immediately as you need immediate treatment in hospital.
Electrocardiogram (ECG)
An electrocardiogram (ECG) can be used to confirm a diagnosis of atrial fibrillation. An ECG is a test that records the rhythm and electrical activity of your heart.
Diagnosis
Checking your pulse is a useful first step in helping to diagnose atrial fibrillation.
Checking your pulse
To check your pulse:
- sit down for 5 minutes – do not smoke or drink caffeine before taking the reading
- hold your left hand out with your palm facing up and elbow slightly bent
- firmly place the index and middle finger of your right hand on your left wrist, at the base of the thumb (between the wrist and the tendon attached to the thumb)
- using the second hand on a clock or watch, count the number of beats for 30 seconds, and then double that number to get your heart rate in beats per minute
At rest, a normal heart rate should be 60 to 100 beats per minute. In atrial fibrillation, the heart rate can often be considerably higher than 100 beats per minute, and each individual beat is erratic.
Heart rhythm charity Arrythmia Alliance has more information about knowing your pulse and how to check it.
Checking and assessing your pulse can give you a good indication of whether you have atrial fibrillation, but a full medical investigation will be needed before a diagnosis can be made.
If atrial fibrillation is suspected, a GP may give you an electrocardiogram (ECG) and refer you to a heart specialist (cardiologist) for further tests.
An electrophysiologist is a cardiologist who specialises in electrical disturbances of the heart.
They can carry out a procedure called catheter ablation to treat your atrial fibrillation.
Electrocardiogram (ECG)
An ECG is a test that records your heart's rhythm and electrical activity. It's usually carried out in a hospital or GP surgery, takes about 5 minutes, and is painless.
During an ECG, small stickers called electrodes are attached to your arms, legs and chest, and connected by wires to an ECG machine.
Every time your heart beats, it produces tiny electrical signals. An ECG machine traces these signals onto paper.
During an episode of atrial fibrillation, your heart rate will be irregular and over 100 beats per minute.
If you have an episode of atrial fibrillation during an ECG, your abnormal heart rate will be recorded. This will confirm the diagnosis of atrial fibrillation and rule out other conditions.
But often it can be difficult to capture an episode of atrial fibrillation, so you may be asked to wear a small portable ECG recorder.
The recorder will either trace your heart rate continuously over 24 hours or when you switch it on at the start of an episode.
Read more about an electrocardiogram (ECG)
Other tests
If you have atrial fibrillation, a number of other tests may be carried out, including:
Treatment
Treatments for atrial fibrillation include medicines to control heart rate and reduce the risk of stroke, and procedures such as cardioversion to restore normal heart rhythm.
It may be possible for you to be treated by a GP, or you may be referred to a heart specialist (a cardiologist).
Some cardiologists, known as electrophysiologists, specialise in the management of abnormalities of heart rhythm.
You'll have a treatment plan and work closely with your healthcare team to decide the most suitable and appropriate treatment for you.
Factors that will be taken into consideration include:
- your age
- your overall health
- the type of atrial fibrillation you have
- your symptoms
- whether you have an underlying cause that needs to be treated
The first step is to try to find the cause of the atrial fibrillation. If a cause can be identified, you may only need treatment for this.
For example, if you have an overactive thyroid gland (hyperthyroidism), medicine to treat it may also cure atrial fibrillation.
If no underlying cause can be found, the treatment options are:
- medicines to reduce the risk of a stroke
- medicines to control atrial fibrillation
- cardioversion (electric shock treatment)
- catheter ablation
- having a pacemaker fitted
You'll be promptly referred to your specialist treatment team if 1 type of treatment fails to control your symptoms of atrial fibrillation and more specialised management is needed.
Medicines to control atrial fibrillation
Medicines called anti-arrhythmics can control atrial fibrillation by:
- restoring a normal heart rhythm
- controlling the rate at which the heart beats
The choice of anti-arrhythmic medicine depends on the type of atrial fibrillation, any other medical conditions you have, side effects of the medicine chosen, and how well the atrial fibrillation responds.
Some people with atrial fibrillation may need more than 1 anti-arrhythmic medicine to control it.
Restoring a normal heart rhythm
A variety of medicines are available to restore normal heart rhythm, including:
- flecainide
- beta blockers, particularly sotalol
An alternative medicine may be recommended if a particular medicine does not work or the side effects are troublesome.
Newer medicines are in development, but are not widely available yet.
Controlling the rate of the heartbeat
The aim is to reduce the resting heart rate to under 90 beats per minute, although in some people the target is under 110 beats per minute.
A beta blocker, such as bisoprolol or atenolol, or a calcium channel blocker, such as verapamil or diltiazem, will be prescribed.
The medicine you'll be offered will depend on what symptoms you're having and your general health.
A medicine called digoxin may be offered if other drugs are not suitable.
If one medicine is not controlling your symptoms, you may be offered another alongside it.
Side effects
As with any medicine, anti-arrhythmics can cause side effects.
The most common side effects of anti-arrhythmics are:
- beta blockers – tiredness, cold hands and feet, low blood pressure, nightmares and impotence
- flecainide – nausea, vomiting and heart rhythm disorders
- verapamil – constipation, low blood pressure, ankle swelling and heart failure
Read the patient information leaflet that comes with the medicine for more details.
Medicines to reduce the risk of a stroke
The way the heart beats in atrial fibrillation means there's a risk of blood clots forming in the heart chambers.
If these enter the bloodstream, they can cause a stroke.
Your doctor will assess your risk and try to minimise your chance of having a stroke.
They'll consider your age and whether you have a history of any of the following:
You may be given medicine according to your risk of having a stroke.
Depending on your level of risk, you may be prescribed warfarin or an anticoagulant, such as dabigatran, rivaroxaban, apixaban or edoxaban.
If you're prescribed an anticoagulant, your risk of bleeding will be assessed both before you start the medication and while you're taking it.
Aspirin is not recommended to prevent strokes caused by atrial fibrillation.
Anticoagulants
Anticoagulants stop your blood from clotting and can help lower your risk of having a stroke.
Direct-acting anticoagulants
Direct-acting anticoagulants such as rivaroxaban, dabigatran, apixaban and edoxaban are recommended for people who have a high or moderate risk of having a stroke.
The National Institute for Health and Care Excellence (NICE) states that you should be offered a choice of anticoagulation and the opportunity to discuss the merits of each medicine.
Rivaroxaban, dabigatran, apixaban and edoxaban do not interact with other medicines and do not require regular blood tests.
Warfarin
Warfarin is an anticoagulant that you may be offered if direct-acting anticoagulants are not suitable for you.
There's an increased risk of bleeding in people who take warfarin, but this small risk is usually outweighed by the benefits of preventing a stroke.
It's important to take warfarin as directed by your doctor. If you're prescribed warfarin, you need to have regular blood tests and, after these, your dose may be changed.
Many medicines can interact with warfarin and cause serious problems, so check that any new medicines you're prescribed are safe to take with warfarin.
While taking warfarin, you should be careful about drinking too much alcohol regularly and avoid binge drinking.
Drinking cranberry juice and grapefruit juice can also interact with warfarin and is not recommended.
Cardioversion
Cardioversion may be recommended for some people with atrial fibrillation.
It involves giving the heart a controlled electric shock to try to restore a normal rhythm.
Cardioversion is usually carried out in hospital so the heart can be carefully monitored.
If you have had atrial fibrillation for more than 2 days, cardioversion can increase the risk of a clot forming.
In this case, you'll be given an anticoagulant for 3 to 4 weeks before cardioversion, and for at least 4 weeks afterwards to minimise the chance of having a stroke.
In an emergency, pictures of the heart can be taken to check for blood clots, and cardioversion can be carried out without going on medication first.
Anticoagulation may be stopped if cardioversion is successful.
But you may need to continue taking anticoagulation after cardioversion if the risk of atrial fibrillation returning is high and you have an increased risk of having a stroke.
Catheter ablation
Catheter ablation is a procedure that very carefully destroys the diseased area of your heart and interrupts abnormal electrical circuits.
It's an option if medicine has not been effective or tolerated.
Catheters (thin, soft wires) are guided through 1 of your veins into your heart, where they record electrical activity.
When the source of the abnormality is found, an energy source, such as high-frequency radiowaves that generate heat, is transmitted through 1 of the catheters to destroy the tissue.
The procedure usually takes 2 to 3 hours, so it may be carried out under general anaesthetic, which means you're unconscious during the procedure.
You should make a quick recovery after having catheter ablation and be able to carry out most of your normal activities the next day.
But you should not lift anything heavy for 2 weeks, and driving should be avoided for the first 2 days.
Although catheter ablation works for most people who have it, there's a small risk the procedure might not work or your symptoms might come back after treatment.
You may be given anti-arrhythmic medicines for 3 months after a catheter ablation to help stop symptoms coming back.
Pacemaker
A pacemaker is a small battery-operated device that's implanted in your chest, just below your collarbone.
It's usually used to stop your heart beating too slowly, but in atrial fibrillation it may be used to help your heart beat regularly.
Having a pacemaker fitted is usually a minor surgical procedure carried out under a local anaesthetic (the area being operated on is numbed and you're conscious during the procedure).
This treatment may be used when medicines are not effective or are unsuitable. This tends to be in people aged 80 or over.