Atrial fibrillation (AF or AFib) is the most common heart rhythm disorder (arrhythmia) in the UK, affecting around 1.4 million people. It occurs when the electrical signals coordinating the heartbeat become chaotic, causing the upper chambers of the heart (atria) to quiver rather than contract properly. AF significantly increases the risk of stroke — people with AF are 5 times more likely to have a stroke — making diagnosis and treatment essential.
How AF Affects the Heart
Normally, the heart’s electrical system generates a regular impulse from the sinoatrial (SA) node, causing the atria and ventricles to contract in sequence. In AF, multiple random electrical impulses fire in the atria at 350–600 beats per minute. The atria quiver ineffectively, and only some signals pass through the AV node to the ventricles — creating a fast, irregular pulse. Blood can pool in the atria (especially in the left atrial appendage), forming clots that can travel to the brain and cause a stroke.
Types of Atrial Fibrillation
- Paroxysmal AF — Episodes come and go; each lasts less than 7 days and often stop on their own; may progress to persistent AF over time
- Persistent AF — Episodes last more than 7 days; does not stop spontaneously; requires treatment to restore normal rhythm
- Long-standing persistent AF — Continuous AF lasting more than 12 months
- Permanent AF — Accepted as ongoing; rate control chosen over rhythm control
- Lone AF — AF with no identifiable underlying cause or structural heart disease, typically in younger patients
Symptoms
AF symptoms vary greatly — some people have no symptoms at all (silent AF, often discovered incidentally). Common symptoms include:
- Palpitations — Heart fluttering, racing, or irregular heartbeat; often described as “heart jumping out of chest”
- Shortness of breath — On exertion or at rest
- Dizziness or lightheadedness
- Fatigue and weakness — Especially on exertion
- Chest discomfort or tightness
- Reduced exercise tolerance
- In severe cases: presyncope (near-fainting) or syncope
Causes and Risk Factors
- Age — Risk doubles with each decade; affects ~10% of people over 80
- High blood pressure (hypertension) — The most common modifiable risk factor
- Heart disease — Coronary artery disease, heart failure, valvular disease (especially mitral valve)
- Thyroid disease — Hyperthyroidism in particular
- Obesity — Major independent risk factor; weight loss reduces AF burden
- Obstructive sleep apnoea
- Alcohol (holiday heart syndrome) — Binge drinking triggers AF episodes
- Diabetes mellitus
- Smoking
- Excessive exercise — Endurance athletes have higher AF rates (“athlete’s heart”)
- Other triggers — Acute illness, chest infection, pulmonary embolism, post-surgery
Diagnosis
- 12-lead ECG — Gold standard; shows absence of P waves and irregularly irregular QRS complexes
- Pulse check — Irregularly irregular pulse; GPs, pharmacists and nurses can detect AF by feeling the pulse
- 24- or 48-hour Holter monitor — Wearable ECG for paroxysmal AF that may not be present at rest
- 7-day or prolonged ECG patch — For infrequent episodes
- Smart devices — Apple Watch, Kardia (AliveCor) — can detect AF; NHS pilots are integrating these into pathways
- Echocardiogram — Assess heart structure and function; check for valvular disease and left ventricular function
- Blood tests — TSH (thyroid), FBC, U&E, LFTs, HbA1c, lipids
Stroke Risk Assessment: CHA₂DS₂-VASc Score
All patients with AF should have their stroke risk assessed using the CHA₂DS₂-VASc score. Anticoagulation is recommended for men scoring ≥2 and women scoring ≥3 (women get 1 point for female sex):
| Factor | Points |
|---|---|
| Congestive heart failure | 1 |
| Hypertension | 1 |
| Age ≥75 years | 2 |
| Diabetes mellitus | 1 |
| Stroke or TIA (prior) | 2 |
| Vascular disease (heart attack, PAD) | 1 |
| Age 65–74 years | 1 |
| Sex category (female) | 1 |
Treatment: Anticoagulation (Stroke Prevention)
Anticoagulation (blood thinning) is the most important aspect of AF treatment — reducing stroke risk by approximately 65%. The NHS preference is for direct oral anticoagulants (DOACs) over warfarin:
- Apixaban (Eliquis) — Twice daily; preferred in most guidelines due to favourable bleeding profile
- Rivaroxaban (Xarelto) — Once daily
- Edoxaban (Lixiana) — Once daily
- Dabigatran (Pradaxa) — Twice daily; reversible with idarucizumab (Praxbind)
- Warfarin — Still used where DOACs are not suitable (e.g. severe kidney disease, mechanical heart valves); requires regular INR monitoring (target 2–3)
Aspirin alone is NOT recommended for stroke prevention in AF — it is ineffective and carries similar bleeding risk to anticoagulants.
Treatment: Rate Control
Rate control slows the ventricular response to AF (target resting heart rate <110 bpm). First-line options include:
- Beta-blockers — Bisoprolol, metoprolol, atenolol; most commonly used; especially if heart failure with reduced ejection fraction
- Calcium channel blockers — Diltiazem, verapamil; not used with heart failure with reduced EF
- Digoxin — Used in sedentary patients or in addition to other agents; less effective during exercise
Treatment: Rhythm Control
Rhythm control aims to restore and maintain normal sinus rhythm. Options include:
- Cardioversion (DCCV) — Electrical shock under general anaesthetic or sedation to restore sinus rhythm; requires anticoagulation for at least 3 weeks before (or TOE to exclude left atrial thrombus)
- Antiarrhythmic drugs — Flecainide (if no structural heart disease), amiodarone (if structural heart disease), sotalol, dronedarone (Multaq)
- Catheter ablation — Minimally invasive procedure; radiofrequency or cryoablation targets the pulmonary vein triggers in the left atrium. NICE recommends it for paroxysmal and persistent AF after drug failure; success rates 60–80% per procedure; increasingly offered earlier in the disease course following the EAST-AFNET 4 and CABANA trials
AF and Heart Failure
AF and heart failure commonly coexist and worsen each other. In patients with AF-induced cardiomyopathy (heart failure caused or worsened by AF), rhythm control (especially ablation) can lead to significant improvement or even normalisation of heart function. This is an important indication for early rhythm control.
Lifestyle Modifications
- Weight loss — Even modest weight loss significantly reduces AF burden and symptoms; 10% weight loss can achieve near-freedom from AF in overweight patients
- Reduce or stop alcohol — Alcohol is a potent AF trigger; abstinence or significant reduction is recommended
- Treat sleep apnoea — CPAP therapy reduces AF recurrence
- Blood pressure control — Optimal BP control reduces AF progression
- Regular moderate exercise — But avoid excessive endurance exercise if it triggers AF
- Smoking cessation
NHS AF Detection and the Know Your Pulse Campaign
NHS England and the Arrhythmia Alliance campaign for opportunistic AF screening, particularly in people over 65. Pharmacists and GP practices regularly offer free pulse checks. If you are over 65 or have risk factors, ask for a pulse check or ECG at your next appointment.
Support and Resources
- AF Association — afassociation.org.uk — Patient information and support; helpline: 01789 867 502
- Arrhythmia Alliance — heartrhythmalliance.org
- British Heart Foundation — bhf.org.uk — Heart helpline: 0300 330 3311
- NHS AF information — nhs.uk/conditions/atrial-fibrillation
This information is for general education. Always consult your GP or cardiologist for personalised advice about your heart rhythm condition.
Related Health Guides on YourHealthXpert
Explore these related NHS-aligned health guides:
- Heart Attack Guide — AF significantly increases heart attack risk through clot formation; understand the cardiovascular connection and NHS anticoagulation guidance.
- Stroke Guide — AF is responsible for around one in five strokes in the UK; learn the FAST signs and how anticoagulants reduce AF-related stroke risk.
- High Blood Pressure Guide — Hypertension is the most common cause of AF; understand how blood pressure control reduces AF episodes and stroke risk.
- High Cholesterol Guide — Cardiovascular risk factors cluster together; learn how managing cholesterol alongside AF reduces overall heart disease risk.
- Type 2 Diabetes Guide — Diabetes doubles the risk of developing AF; understand how blood sugar control helps cardiac rhythm management.
- DVT Guide — Both AF and DVT involve clotting risk; understand how anticoagulation treatment works for both conditions under NHS care.