Atrial Fibrillation (AF)
Atrial Fibrillation: Symptoms, Causes & Treatment
In short
Atrial fibrillation is an irregular, often fast heart rhythm. It raises the risk of stroke, so it needs assessing even when symptoms are mild or absent. It is confirmed on an ECG (a heart monitor may be needed if it comes and goes), and treatment aims to lower stroke risk, often with an anticoagulant, and to control the rate or rhythm. Call 999 for chest pain, severe breathlessness, fainting or signs of a stroke.
Atrial fibrillation overview
Atrial fibrillation (AF, also written AFib) is the most common sustained heart rhythm disturbance. The two upper chambers of the heart (the atria) fire rapid, disorganised electrical signals, so they quiver instead of contracting properly, and the lower chambers (the ventricles) respond irregularly and often too fast. Because blood can pool in the atria, particularly in a small pouch called the left atrial appendage, clots can form and travel to the brain. This is why AF raises the risk of stroke.
AF becomes more common with age and is often linked to high blood pressure, coronary artery disease, heart valve disease, heart failure, an overactive thyroid, obesity, diabetes, obstructive sleep apnoea and regular heavy alcohol intake. It can also occur with no identifiable cause, including in some younger and otherwise healthy people.
AF is not usually immediately life-threatening, but without treatment it is associated with roughly a five-fold increase in stroke risk and can contribute to heart failure, reduced stamina and poorer quality of life. The encouraging news is that stroke risk can be measured and substantially reduced, and symptoms can be treated effectively. With proper assessment, most people with AF live full, active lives.
Types of AF
Paroxysmal – episodes start and stop on their own, usually within 7 days.
Persistent – continuous AF lasting more than 7 days, or needing treatment such as cardioversion to stop.
Long-standing persistent – continuous AF for 12 months or more, where a rhythm-control strategy is still being considered.
Permanent – AF that you and your doctor have agreed to accept, with no further attempts to restore normal rhythm.
Medically reviewed by Dr Salam Salloum, Consultant Cardiologist (GMC 5209498). Last reviewed: 8 October 2026. This page is for general information and does not replace individual medical advice.
Atrial fibrillation symptoms and signs
The hallmark of AF is an irregularly irregular pulse: there is no repeating pattern, and the rate is often (but not always) faster than normal. Episodes can last minutes, hours or days, or be continuous. Symptoms vary widely. Some people are very aware of their heartbeat, while others notice nothing at all.
Cardiovascular symptoms
Palpitations – a fluttering, pounding or racing heartbeat
An irregular or uneven pulse
Chest discomfort or tightness
Shortness of breath, especially on exertion or when lying flat
Feeling faint or light-headed
General symptoms
Fatigue or unusual tiredness
Dizziness
Sweating
Anxiety related to the sensation of an irregular heartbeat
Passing more urine than usual during an episode
Reduced stamina and exercise tolerance
Reduced capacity for physical activity
Breathlessness on stairs, hills or brisk walking
Heart rate that rises quickly with effort
Fatigue that lingers after activity
Silent AF: when there are no symptoms
A significant number of people have AF without noticing anything. It may be found by chance on a routine pulse check, an ECG, a smartwatch alert, or, unfortunately, after a stroke. UK guidance (NICE) advises checking the pulse in anyone with breathlessness, palpitations, dizziness or fainting, chest discomfort, or a stroke or TIA, followed by an ECG if the pulse is irregular.
Causes and risk factors of atrial fibrillation
AF rarely has a single cause. It usually develops when several factors act on the heart over time, and in some people no clear cause is found. Understanding yours matters, because treating an underlying cause can reduce AF episodes as well as protect your heart.
Heart and circulation conditions
High blood pressure is the most common underlying cause. Over time it thickens and stiffens the heart and stretches the upper chambers.
Coronary artery disease and previous heart attack.
Heart failure and cardiomyopathy (disease of the heart muscle).
Heart valve disease, particularly of the mitral valve.
Congenital heart conditions and previous heart surgery.
Inflammation around the heart (pericarditis or myocarditis).
Other medical conditions
An overactive thyroid gland (hyperthyroidism).
Type 2 diabetes and obesity.
Obstructive sleep apnoea, where breathing repeatedly pauses during sleep. It is common and often missed.
Chronic kidney disease and lung conditions such as COPD.
Acute illness, such as a chest infection, or the days after surgery, can trigger AF, sometimes for the first time.
Lifestyle factors
Alcohol: both regular heavy drinking and a single heavy session (sometimes called holiday heart) can trigger AF.
Smoking.
Stimulant drugs such as cocaine and amphetamines.
Physical activity: being inactive raises the risk, and in some people many years of very high-volume endurance training is also linked to AF. Regular moderate exercise is protective.
Caffeine: moderate tea or coffee has not been shown to trigger AF in trials.
Factors you cannot change
Age. AF becomes more common as we get older.
Family history. Inherited factors play a part, especially when AF starts at a young age. Tell your cardiologist if close relatives have AF.
Common triggers of an episode
In people who already have AF, an episode can be set off by heavy alcohol, infection or other illness, dehydration, poor sleep, stress or emotional upset, stimulant drugs and some medicines (check with a pharmacist before buying cold and flu remedies). A simple diary of when episodes happen, and what you were doing, helps to identify your own triggers.
Can AF be prevented?
Not always, but the risk can be lowered. Keep blood pressure and diabetes well controlled, aim for a healthy weight, keep alcohol low, stay active (about 150 minutes of moderate activity a week), do not smoke, and have sleep apnoea treated if you have it. If you notice palpitations or an irregular pulse, have them checked rather than waiting.
When no cause is found
Sometimes no cause can be identified. This does not change how AF is treated: your stroke risk is assessed in the same way and the same options for stroke prevention and symptom control apply.
When to see a doctor about atrial fibrillation
AF should always be properly assessed, even if episodes settle by themselves. Your stroke risk depends on your overall risk factors, not on whether AF is present at that moment or how strongly you feel it.
Arrange a prompt cardiology assessment if you notice:
New or recurrent palpitations or an irregular pulse
An irregular rhythm flagged by a smartwatch, home blood pressure monitor or pulse check
Unexplained tiredness, breathlessness, dizziness or reduced exercise tolerance
Known AF with a change in your symptoms, or side effects from your medication
New symptoms alongside high blood pressure, thyroid disease, heart valve disease or heavy alcohol use
Unusual bleeding or bruising if you take an anticoagulant (contact your doctor promptly and do not stop the medicine yourself)
Call 999 immediately if you have:
Signs of a stroke: face drooping, arm weakness or slurred speech (call 999 even if symptoms pass)
Chest pain or pressure, especially with breathlessness or sweating
Fainting or collapse
Severe breathlessness at rest
A very fast heartbeat with feeling extremely unwell
Heavy bleeding that will not stop, or a head injury, while taking an anticoagulant
How atrial fibrillation is diagnosed
AF is diagnosed by recording the heart rhythm. The 2024 European Society of Cardiology guidelines require an ECG, either a 12-lead tracing or a single-lead recording of at least 30 seconds, showing irregularly irregular R-R intervals with no distinct, repeating P waves. Because AF often comes and goes, a normal ECG does not rule it out and extended monitoring is frequently needed to catch episodes. Your cardiologist will also look for reversible triggers and underlying conditions.
1. Electrocardiogram (ECG)
The ECG confirms AF if it is present during the recording. Single-lead recordings from consumer devices (such as AliveCor Kardia or the Apple Watch) can raise suspicion but should be reviewed by a clinician and confirmed. Our professional ECG reporting service provides consultant-reviewed interpretation of 12-lead, 6-lead, 3-lead and single-lead tracings, UK-wide.
2. Extended rhythm monitoring (Holter and patch monitors)
When symptoms come and go, a wearable recorder worn for anything from 24 hours to 14 days can capture the episodes. The best duration depends on how often symptoms occur: daily symptoms may be caught within 24–48 hours, weekly symptoms within 5–7 days, and infrequent or unpredictable symptoms may need 14 days. We provide nationwide cardiac monitoring, with devices delivered to your home anywhere in the UK and recordings reviewed by Dr Salloum.
3. Echocardiogram
An ultrasound scan of the heart checks heart size, pumping function, the size of the left atrium and the heart valves. It identifies conditions such as valve disease or heart failure that influence both the cause of AF and the choice of treatment (for example, whether warfarin rather than a DOAC is needed). Where exercise-related symptoms or coronary artery disease are a concern, an exercise stress echo may also be recommended.
We offer a private echocardiogram in Peterborough, Corby and London.
4. Blood tests and risk assessment
Blood tests usually include thyroid function, kidney and liver function, electrolytes and a full blood count, with glucose or HbA1c and cholesterol where appropriate. Your cardiologist will then estimate your stroke risk using a validated score such as CHA₂DS₂-VASc (which accounts for age, sex, high blood pressure, diabetes, heart failure, and previous stroke or vascular disease) and assess bleeding risk with a tool such as ORBIT, mainly to identify and correct modifiable risks. Screening for sleep apnoea is also worthwhile in many patients.
Tests and services that may help
We can arrange the investigations used to diagnose and manage AF:
ECG reporting: consultant review of 12-lead, 6-lead, 3-lead and single-lead tracings, UK-wide.
Cardiac monitoring: Holter and patch monitors delivered to your home to catch episodes that come and go.
Echocardiogram: an ultrasound scan of the heart in Peterborough, Corby and London.
Consultation by telephone, video or face to face to review your results and agree a plan.
Atrial fibrillation treatment options
Modern AF care follows the structured AF-CARE approach set out in the 2024 European Society of Cardiology guidelines, consistent with NICE guidance in the UK: manage Comorbidities and risk factors, Avoid stroke, Reduce symptoms with rate and rhythm control, and Evaluate and reassess regularly. Treatment is individualised and agreed with you through shared decision-making. A visual summary is available under “Visual aids”.
1. Stroke prevention (anticoagulation)
Anticoagulation (“blood thinners”) is the single most important treatment for preventing AF-related stroke. It is generally recommended when your stroke-risk score is 2 or more, and should be considered when it is 1, whether your AF is intermittent or permanent and however mild your symptoms.
DOACs (apixaban, edoxaban, rivaroxaban, dabigatran) are preferred over warfarin for most people, with at least equivalent protection and less bleeding in the brain. Warfarin remains the choice with mechanical heart valves or moderate-to-severe mitral stenosis.
Effective anticoagulation reduces the risk of stroke by roughly two-thirds. Aspirin alone is not recommended for stroke prevention in AF.
A higher bleeding risk is usually a reason to correct modifiable factors (blood pressure, alcohol, interacting medicines such as anti-inflammatory painkillers) rather than to withhold treatment.
If long-term anticoagulants cannot be used, left atrial appendage occlusion may be considered by a specialist team.
2. Rate control
The aim is to slow the ventricular rate so that you feel better and the heart works efficiently, even if AF continues.
Beta-blockers or rate-limiting calcium-channel blockers (diltiazem, verapamil) are the usual first choices. Digoxin may be used in less active people or added to other drugs. Diltiazem and verapamil are avoided if the heart’s pumping function is reduced.
A resting heart rate below about 110 beats per minute is an acceptable initial target if you have no troublesome symptoms, with tighter control if symptoms persist.
If drugs fail, AV node ablation with a pacemaker is an option in selected patients.
3. Rhythm control
Cardioversion restores normal rhythm with a brief, controlled electrical shock under sedation (or with medication). Anticoagulation is needed for at least 4 weeks afterwards, and beforehand unless AF began very recently or imaging excludes a clot.
Antiarrhythmic drugs (such as flecainide, sotalol, amiodarone or dronedarone) are chosen according to the structure and function of your heart.
Catheter ablation isolates the pulmonary veins, where many AF triggers arise. It is recommended when drugs are ineffective or not tolerated, and is increasingly offered earlier to selected patients. Success is higher in paroxysmal than in long-standing AF, and some people need more than one procedure.
Evidence from the EAST-AFNET 4 trial suggests that starting rhythm control early, within a year of diagnosis, can reduce cardiovascular complications in suitable patients.
The decision to continue anticoagulation depends on your stroke risk, not on whether normal rhythm has been restored.
4. Lifestyle and risk-factor management
Alcohol: cutting down or abstaining reduces AF recurrence in people who drink regularly.
Weight: sustained weight loss (around 10% of body weight or more) is linked to a marked reduction in AF burden.
Blood pressure, diabetes and cholesterol: keep well controlled.
Sleep apnoea: treat it if present.
Physical activity: regular moderate exercise (around 150 minutes a week) is beneficial.
Caffeine: moderate tea or coffee has not been shown to trigger AF in trials, but if you notice a personal trigger it is sensible to avoid it.
Smoking and stress: stopping smoking and improving sleep and stress management all help.
Living with atrial fibrillation
An AF diagnosis can feel worrying at first, but most people adapt well once the right treatment is in place and they understand their condition. Small daily habits make a real difference to both symptoms and safety.
Practical steps for living well with AF
Take medication exactly as prescribed, particularly anticoagulants. Never stop or skip them without medical advice.
Learn to check your pulse and keep a simple symptom diary (when episodes occur, how long they last, possible triggers).
Carry an anticoagulant alert card and tell dentists, pharmacists and other clinicians that you take one before any procedure.
Check before taking over-the-counter painkillers. Anti-inflammatories such as ibuprofen or aspirin increase bleeding risk when combined with an anticoagulant.
Attend regular reviews, at least yearly, so your stroke risk, bleeding risk, kidney function and medicines can be rechecked.
Stay active and keep alcohol low, as these are among the most effective things you can do for your rhythm.
Driving: the rules depend on your symptoms and licence type. Follow DVLA guidance and discuss it with your cardiologist if AF causes dizziness or fainting.
Look after your wellbeing. Anxiety about the heartbeat is common and treatable. Support is available from the Atrial Fibrillation Association, the British Heart Foundation, the NHS and the Stroke Association.
Driving, work and travel
Many people with AF carry on driving, but the DVLA rules depend on your symptoms and the type of licence you hold. For car and motorcycle (Group 1) licences, based on DVLA guidance last updated 7 November 2025:
Do not drive if AF has caused, or is likely to cause, incapacity such as fainting. You may drive again 4 weeks after the cause has been identified and treated with no recurrence, and you must tell the DVLA.
After catheter ablation you usually should not drive for 2 days. You need not tell the DVLA.
Bus, coach and lorry (Group 2) rules are stricter, and significant rhythm problems must be reported to the DVLA.
Rules change, so always check GOV.UK, and see our DVLA cardiac assessment page if you drive for work. Most people with AF can continue to work. If your job is safety-critical or physically demanding, discuss it with your cardiologist. Flying is generally safe once AF is stable and treated: carry your medicines in your hand luggage and check that your travel insurance covers existing heart conditions.
Atrial fibrillation prognosis and outlook
With appropriate treatment, stroke risk can be reduced substantially, and most people achieve good symptom control with rate or rhythm control.
AF is often a long-term condition that needs ongoing review. In some people, paroxysmal AF progresses over time to persistent AF, particularly with uncontrolled high blood pressure, obesity, sleep apnoea, regular heavy alcohol intake or underlying heart disease, which is why addressing these early matters.
Early rhythm control and catheter ablation can maintain normal rhythm in many people, with better results in earlier-stage AF. Some people need repeat procedures or continued medication.
Untreated or poorly controlled AF is linked with a higher risk of stroke, heart failure and hospital admission. Effective anticoagulation and rate or rhythm control greatly reduce these risks.
Your outlook depends on your age, other medical conditions, heart structure and how well risk factors are controlled. Regular reviews allow treatment to be adjusted over time.
Atrial fibrillation key facts
AF is the most common sustained heart rhythm disturbance and becomes more common with age.
Its hallmark is an irregularly irregular pulse, often fast, but some people have no symptoms at all.
AF raises stroke risk by roughly five-fold, so stroke prevention is the central aim of treatment.
Your stroke risk depends on your risk factors (for example CHA₂DS₂-VASc), not on whether AF is present at the moment or how much you feel it.
An ECG confirms the diagnosis, but because AF often comes and goes, extended monitoring may be needed to catch it.
Management follows AF-CARE: comorbidities and risk factors, avoiding stroke, reducing symptoms with rate or rhythm control, and ongoing evaluation.
DOACs are preferred over warfarin for most people, and aspirin alone is not recommended for stroke prevention in AF.
Common contributors are high blood pressure, valve disease, heart failure, thyroid disease, sleep apnoea, obesity and alcohol.
Reducing alcohol, losing excess weight, controlling blood pressure and staying active can reduce how often AF occurs.
Many people achieve good long-term control with medication, lifestyle changes, cardioversion or catheter ablation.
Guidelines and sources
This page follows current UK and European guidance:
NICE NG196: Atrial fibrillation: diagnosis and management (2021).
Van Gelder IC et al. 2024 ESC Guidelines for the management of atrial fibrillation. European Heart Journal 2024;45:3314-3414.
DVLA: Cardiovascular disorders: assessing fitness to drive (GOV.UK).
Atrial fibrillation questions and answers
These are the questions patients most often ask about atrial fibrillation.
What is atrial fibrillation?
Atrial fibrillation (AF) is the most common sustained heart rhythm disturbance. The two upper chambers of the heart quiver instead of contracting properly, so the heartbeat becomes irregular and often fast. It is treatable, and with the right care most people live normally.
Is atrial fibrillation dangerous?
AF is not usually immediately life-threatening, but it raises the risk of stroke by roughly five times because clots can form in the upper chambers and travel to the brain. This is why assessing your stroke risk and, when needed, taking an anticoagulant is the most important part of treatment. AF can also weaken the heart over time if the rate stays fast, so it should always be assessed.
Does AF always cause symptoms?
No. Some people feel palpitations, breathlessness or tiredness, while others have no symptoms and AF is found on a routine pulse check, an ECG or a smartwatch alert. Your stroke risk does not depend on how strongly you feel the AF.
Can AF go away on its own?
Yes. In paroxysmal AF the episodes start and stop by themselves, usually within 7 days. In some people it becomes persistent or permanent over time. Because AF comes and goes, a normal ECG does not rule it out, and extended monitoring is often needed.
Do I need to take a blood thinner?
It depends on your individual stroke risk, which your cardiologist works out with a score such as CHA₂DS₂-VASc (age, sex, blood pressure, diabetes, heart failure, and previous stroke or vascular disease). An anticoagulant is generally recommended when the score is 2 or more, and considered when it is 1. Your bleeding risk is also assessed so that it can be reduced where possible.
Is aspirin enough to prevent a stroke?
No. Aspirin alone is not recommended for stroke prevention in AF. It is much less effective than an anticoagulant and still carries a bleeding risk.
Can I stop my blood thinner if my heart rhythm returns to normal?
Not on your own. Stroke risk depends on your risk factors, not on whether you are in AF at that moment. Never stop or skip an anticoagulant without advice from your cardiologist.
Can alcohol, caffeine or stress trigger AF?
Alcohol is a well-recognised trigger, and cutting down reduces the chance of AF returning. The 2024 European guideline advises keeping to no more than about 3 standard drinks (30 g of alcohol) a week. Moderate tea or coffee has not been shown to trigger AF in trials, but if you notice a personal trigger it is sensible to avoid it. Stress, poor sleep, illness and dehydration can also set off episodes.
Can I exercise with AF?
Yes, and regular activity helps. The 2024 European guideline recommends a tailored programme of around 150 to 300 minutes a week of moderate activity. Build up gradually. If exercise brings on palpitations, breathlessness, dizziness or chest discomfort, have it assessed first, as a stress test is sometimes helpful.
Can AF be cured?
AF is usually a long-term condition, but it can be controlled well. Catheter ablation can maintain normal rhythm in many people, with better results in earlier, paroxysmal AF, and some people need more than one procedure or continued medication. Controlling blood pressure, weight, alcohol intake and sleep apnoea improves the chance of success.
Can my smartwatch diagnose AF?
A smartwatch or single-lead device can raise suspicion of AF, but the diagnosis needs an ECG recording (a 12-lead tracing, or a single-lead recording of at least 30 seconds) reviewed by a clinician. Our professional ECG reporting service provides consultant review of tracings from home devices, UK-wide.
Can I drive if I have AF?
Often yes, but it depends on your symptoms and your licence. You should not drive if AF has caused, or is likely to cause, fainting or other symptoms that could affect your driving, and in that situation you must tell the DVLA. The “Living with it” tab summarises the rules, and our DVLA cardiac assessment page explains how we can help.
Can I have an AF assessment privately?
Yes. A consultation by telephone, video or face to face in Peterborough or Corby can review your symptoms and stroke risk, with an ECG and echocardiogram arranged as needed. ECG reporting and cardiac monitoring are available across the UK.
Questions to ask your cardiologist about atrial fibrillation
What type of AF do I have (paroxysmal, persistent, long-standing persistent or permanent)?
What is my individual stroke risk, and do I need an anticoagulant? Which one suits me best?
What is my bleeding risk, and what can I do to lower it?
Could an underlying condition, such as high blood pressure, thyroid disease, valve disease or sleep apnoea, be contributing?
Is rate control or rhythm control more appropriate for me?
Am I a candidate for cardioversion or catheter ablation, and what are the benefits and risks?
Which lifestyle changes will make the biggest difference to my AF?
How should I monitor my pulse and symptoms at home, and when should I seek urgent help?
Do I need further tests, such as extended rhythm monitoring, an echocardiogram or a stress echo?
How often should I be reviewed, and by whom?
Atrial fibrillation diagrams and visual aids
Atrial fibrillation: the upper chambers beat chaotically instead of contracting in time.
Image: BruceBlaus, Atrial Fibrillation, Wikimedia Commons. Licensed under CC BY-SA 4.0.
Normal rhythm compared with atrial fibrillation
Illustrated heartbeat strips: normal rhythm (top) and atrial fibrillation (bottom).
In normal rhythm the beats are evenly spaced. In atrial fibrillation the upper chambers quiver instead of beating properly, so the beats become uneven and the small bump before each beat disappears. This is what a cardiologist looks for when reporting an ECG.
The four types of AF
AF is classified by how long episodes last and whether restoring normal rhythm is still being pursued.
The type of AF influences whether treatment aims to control the heart rate or restore normal rhythm. Your need for stroke prevention depends on your risk factors, not on the type of AF.
Looking after AF: the four parts of care
The four parts of looking after atrial fibrillation.
Treatment is not just about the heartbeat. Looking after your general health, preventing stroke, controlling symptoms and having regular reviews all work together to give the best long-term outcome.
If you have palpitations, an irregular pulse or a diagnosis of atrial fibrillation, you may benefit from a telephone consultation or video consultation to discuss your symptoms and stroke risk, or a face-to-face consultation in Peterborough or Corby for a more comprehensive assessment.
Investigations such as ECG reporting, cardiac monitoring and exercise stress echo may be recommended to further evaluate your heart rhythm.
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Medically reviewed by Dr Salam Salloum, Consultant Cardiologist. Last reviewed: . This page is for general information and does not replace personal medical advice.