Atrial fibrillation, also called AF or AFib, is a heart rhythm condition in which the upper chambers of the heart beat irregularly. Episodes may come and go, persist until treated or become permanent. Some people have no symptoms and the condition is found during a routine examination.
Common symptoms
- An irregular pulse
- Palpitations, fluttering or a racing heartbeat
- Tiredness or reduced ability to exercise
- Shortness of breath
- Dizziness, lightheadedness or feeling faint
- Chest discomfort
Why atrial fibrillation matters
AF can allow blood clots to form in the heart, increasing the risk of stroke. It can also contribute to heart failure. An individual stroke risk assessment helps determine whether anticoagulant medicine is recommended. Never stop an anticoagulant or heart medicine without medical advice.
Diagnosis
An electrocardiogram, or ECG, is used to record the heart rhythm. If episodes are intermittent, longer monitoring may be needed. Other tests can include blood tests, an echocardiogram and checks for conditions that may contribute, such as high blood pressure, thyroid disease, diabetes, sleep apnoea or heart valve disease.
Treatment
Treatment aims to control the heart rate or rhythm and reduce the risk of stroke. Options may include medicines, electrical cardioversion, catheter ablation or a pacemaker in selected cases. The right approach depends on symptoms, other health conditions, how long AF has been present and personal preferences.
Managing blood pressure, maintaining a healthy weight, limiting alcohol, not smoking, staying active and treating sleep apnoea can support heart health. Some people notice triggers such as dehydration, lack of sleep or excess alcohol.
When to get help
Arrange a medical assessment for repeated palpitations, an irregular pulse or worsening symptoms. Call emergency services immediately if a fast or irregular heartbeat occurs with chest pain, severe breathlessness, fainting, sudden weakness or numbness, facial drooping, confusion, difficulty speaking, or sudden loss of vision.
Sources
Reviewed: 28 August 2026