This information is intended for members of the public in UK only.

What is atrial fibrillation (AF)?

AF is a heart condition that makes your heart beat out of rhythm and this can sometimes be fast.

Some people with AF do not experience any symptoms, although a fast heartbeat may be felt (some people describe these as ‘palpitations’). Other possible symptoms include:

  • Tiredness
  • Shortness of breath
  • Chest pain (angina)
  • Dizziness

AF can also be described as ‘persistent’, when episodes last seven days or more, ‘paroxysmal’ which spontaneously terminates within 7 days, usually within 48 hours, or ‘permanent’, when the heart rhythm disturbance is continuous.

The heart is made up of four chambers - the left and right atria (two upper chambers), and the left and right ventricles (two lower chambers).

AF occurs when chaotic electrical activity develops in the atria, disturbing your heart’s natural rhythm. As a result, the atria don’t contract properly, which means your heart cannot pump blood as efficiently as usual.

what is atrial fibrillation supporting image of upper chambers of the heart
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Reference information

This section contains reference information only, is general in nature and intended to provide a general overview of atrial fibrillation for the general public in the UK. It is not intended to replace in any way the opinion of a healthcare professional. For specific information about this pathology and/or detection, diagnosis, prognosis, administration and, where applicable, appropriate treatment for each specific case, please promptly consult a healthcare professional. The use of this website is subject to the legal notice, the privacy and cookie policy, and the applicable laws and regulations.