Atrial fibrillation
Also called: AF, AFib
Chaotic electrical activity in the upper chambers makes the heart beat irregularly and often fast. The atria stop contracting properly, so clots can form and travel to the brain — AF raises stroke risk about five-fold.
Condition-specific references are below. Individual claims and this page have not been clinically reviewed. Read about this content.
The most common sustained arrhythmia; about 1 in 4 adults will develop it in their lifetime.
What happens in the body
Rapid, disorganised impulses — often starting in the pulmonary veins — bombard the AV node, producing an irregular ventricular rhythm. Blood stagnates in the left atrial appendage, where clots form.
Causes
- High blood pressure
- Heart valve disease and heart failure
- Coronary disease
- Overactive thyroid
- Alcohol ("holiday heart")
- Obesity and sleep apnoea
- Lung disease and infection
- Sometimes no cause (lone AF)
Risk factors
- Age
- Hypertension
- Obesity
- Diabetes
- Heavy alcohol use
- Endurance athletics
- Family history
Symptoms
- Palpitations — irregular, fast or fluttering heartbeat
- Breathlessness
- Tiredness and reduced exercise tolerance
- Dizziness
- Chest discomfort
- Many people have no symptoms
Diagnosis — tests and examinations
- Irregularly irregular pulse
- ECG confirms AF
- Holter or event monitoring for intermittent AF; smartwatches may prompt diagnosis
- Echocardiogram and thyroid function tests
- Stroke risk score (CHA₂DS₂-VASc) and bleeding assessment
Treatment
Medicines and medical treatment
- Anticoagulation (apixaban, rivaroxaban, edoxaban, dabigatran or warfarin) for those at stroke risk
- Rate control: beta-blockers, diltiazem/verapamil, digoxin
- Rhythm control: flecainide, amiodarone and others
Operations and procedures
- Electrical cardioversion
- Catheter ablation (pulmonary vein isolation) — often first choice in younger symptomatic patients
- Left atrial appendage occlusion if anticoagulants cannot be taken
- Pacemaker with AV-node ablation in selected cases
Self-care, home remedies and lifestyle
- Weight loss, alcohol reduction and treatment of sleep apnoea reduce AF burden
- Control blood pressure
- Regular moderate exercise
- Never stop anticoagulants without medical advice
Possible complications
- Stroke and other embolism
- Heart failure
- Tachycardia-induced cardiomyopathy
- Dementia
Prevention
- Treat high blood pressure
- Healthy weight, moderate alcohol, treat sleep apnoea
Outlook
With anticoagulation and good rate or rhythm control, most people live normal lives; stroke prevention is the key.
When to see a doctor
See a doctor for palpitations or an irregular pulse. Seek emergency care for chest pain, fainting, severe breathlessness or any stroke symptoms.
Sources and further reading
These sources cover this condition. They have not been checked against every statement on this page.
Related conditions
Educational overview, not medical advice. Treatment varies by person and location. Consult a qualified health professional for diagnosis or care. Read our content and model notes and privacy information.