Atrial fibrillation (AF) is a heart condition that causes an irregular heartbeat. It is the most common disturbance of the heart rhythm and affects up to 10 in 100 (10%) people over the age of 65. AF may be associated with symptoms such as palpitations, breathlessness and dizziness, or it may be asymptomatic (no symptoms are experienced).

Some people have AF all the time, for others it comes and goes (paroxysmal AF). This can make it difficult to detect.

Atrial fibrillation increases the risk of stroke by approximately 500%, but treatment with blood thinning (anticoagulant) medication can reduce this risk. The condition is also associated with an increased risk of heart failure, myocardial infarction (heart attacks) and death, and treatment with anticoagulant medication can also reduce these risks. There is also evidence suggesting a link between AF and dementia.

Three in 100 (3%) people aged 75 have AF without knowing it. About ten in 100 (10%) strokes happen in people unaware they have AF.

For further information about AF please see the NHS Choices website.