When the heart beats normally, its muscular walls contract (tighten and squeeze) to force blood out and around the body. They then relax, so the heart can fill with blood again. This process is repeated every time the heart beats.

AF can cause problems including dizziness, shortness of breath and tiredness.

A normal heart rate should be regular and between 60 and 100 beats per minute when resting.

You should make an appointment to see your GP if:

Most people with AF will require an anticoagulant, but a small number of these won't as it depends on the risk.

AF can increase the risk of a blood clot forming inside the heart. If the clot travels to the brain, it can lead to a stroke.