What does it feel like?
Some people feel a fluttering or racing heartbeat, breathlessness, tiredness or dizziness; others have no symptoms at all and it is found by chance. An irregular pulse is the classic sign.
AF can come and go (paroxysmal) or be persistent. It becomes more common with age and with conditions such as high blood pressure.
Why it matters: stroke risk
In AF, blood can pool and form clots in the heart, which may travel to the brain and cause a stroke. Because of this, doctors assess each person's stroke risk and often recommend a blood-thinning medicine (anticoagulant) to reduce it.
Treatment also focuses on controlling the heart rate or rhythm and treating any underlying cause. Seek urgent help for chest pain, severe breathlessness, or stroke symptoms.
Common questions
Is atrial fibrillation dangerous?
AF itself is rarely immediately life-threatening, but its main danger is a higher risk of stroke, which is why anticoagulation is often advised. It is important to have it assessed and managed.
Related tools
These calculators are designed for healthcare professionals.