Atrial fibrillation


AF is a heart condition – more specifically a type of irregular heartbeat. It means your heart is not working as well as it should be and may make you more likely to have a stroke. More than 1 million people in the UK are living with AF, and it is more common as we get older.1

What is a stroke?

A stroke happens when the blood supply to part of the brain is cut off. This could be due to a blockage in an artery (ischaemic stroke) or by bleeding in the brain (haemorrhagic stroke). A transient ischemic attack (TIA) or mini stroke is similar to a stroke, but the symptoms are temporary.

Stroke is a debilitating disease which can affect bodily functions, thought processes, learning abilities, and how to feel and communicate. The effect of strokes are sudden and symptoms include feeling numb, weak or paralysed on one side of the body, slurred speech and difficulty in finding words or understanding speech. Some people lose their sight or have blurred vision, and others become confused or unsteady.

How is AF linked to stroke?

How is AF linked to stroke? Your heart is a muscle and its job is to pump blood around the body – this pumping action creates your pulse. A normal pulse (when resting) is regular and between 60 to 100 beats a minute. If you have AF, your heart has episodes where it beats faster and in an irregular way – sometimes more than 140 times a minute. You can measure your heart rate by feeling the pulse in your wrist or neck.

If you have a fast or irregular heartbeat, your heart may not have a chance to relax and empty itself of blood properly before filling up again. As a result, the blood does not move quickly and smoothly, and can form clots. If these blood clots then travel in the blood stream to the brain, they could block the blood flow to part of your brain and cause a stroke or TIA.

The diagrams below help explain this process.

AF Process

As you have been diagnosed with AF, your doctor will assess your personal risk of stroke. One method your doctor may use is the CHA2DS2-VASc scoring system below:

CHA2DS2-VASc and how it is calculated
C Congestive cardiac failure 1 point
H Hypertension 1 point
A2 Age greater than 75 years 2 points
D Diabetes 1 point
S2 Stroke or TIA/thromboembolism 2 points
V Vascular disease 1 point
A Age 65-74 1 point
Sc Sex (i.e. female) 1 point

The CHA2DS2-VASc scoring system is used to assess whether anticoagulation medicine (a type of drug that slows down your body’s ability to clot, therefore reducing the likelihood of clots forming), is required. Treatment is recommended when your score is two or more, however in some instances treatment may even be recommended with a score of below two. Your doctor will decide your personalised treatment plan depending on your stroke risk.


  1. Atrial Fibrillation Association, available at: last accessed July 2014