What is atrial fibrillation?

If you have reached this website, it is likely that you or somebody you care for has been examined for, or diagnosed with, atrial fibrillation.

Atrial fibrillation – also known as AF or AFib – is a common heart condition that causes an irregular and often abnormally rapid heart rhythm (arrhythmia), caused when electrical signals fire off from different places in the upper chambers of the heart in a chaotic way.1-3 It is the most common heart rhythm condition,– in fact, AF affects over 33.5 million people worldwide, so you may already know somebody else who has it.2

AF itself is not usually life-threatening, but it can make you more likely to have heart-related complications.1,2 Because of these potential complications, it is very important that you visit your doctor to determine an appropriate treatment plan.

Watch a short animation explaining AF

The heart is made up of four chambers

The upper two chambers, known as the atria, send small electrical signals, which cause the heart to contract at even and consistent intervals.1 The two lower chambers, known as the ventricles, pump the blood around the body in response to these signals.1

If you have a normal, rhythmic heartbeat……

You are said to be in sinus rhythm.2 This name comes from a small group of specialised cells called the sinus node, located in the upper corner of the right atrium.1 The sinus node acts as a natural pacemaker for the heart by generating strong electrical impulses that cause the heart to contract.1

If you have AF……

Your sinus node is no longer regulating these contractions. Instead, these electrical impulses are chaotic and fire off from different points in the atria at different times.1 These irregular contractions of the heart can sometimes feel like the heart is twitching or fluttering (‘fibrillation’). This sensation is often one of the main reasons people decide to see their doctor.1 However, not all people with AF may experience symptoms.1


Without treatment, AF can increase your chance of having a stroke by 4 to 5 times3

Even if you do not have any symptoms, AF can prevent your heart from pumping blood efficiently around the body – sometimes this means that the blood can pool in the atria and form a thick blob, known as a ‘blood clot’.1,3 If this occurs and a clot – or bits of a clot – break loose, they can travel through the bloodstream. If a clot blocks blood flow to the brain, it may cause a stroke.1,3

If you have been diagnosed with AF, your doctor may prescribe an anticoagulant to reduce your risk of a stroke3

An anticoagulant is sometimes known as a blood thinner, and is prescribed to help reduce your risk of stroke. Although anticoagulants do not actually ‘thin’ the blood, they do make it harder for blood clots to form.

It is always important to take your anticoagulant as prescribed by your doctor, even if you feel fine

Although an anticoagulant will not treat your AF, stroke prevention is important for you and your doctor to consider when discussing an appropriate treatment plan.3

1. Mayo Clinic. Atrial fibrillation. June 2019. Available at  https://www.mayoclinic.org/diseases-conditions/atrial-fibrillation/symptoms-causes/syc-20350624. Last accessed November 2020. 

2. Morillo CA et al. J Geriat Cardiol 2017; 14: 195–203. 

3. Stroke Association. Atrial fibrillation. Available at https://www.stroke.org.uk/what-is-stroke/are-you-at-risk-of-stroke/atrial-fibrillation. Last accessed November 2020. 

PP-ELI-HKG-0637 JUN 2021