Can atrial fibrillation cause stroke?

During atrial fibrillation, the upper chambers quiver instead of squeezing in a coordinated way. Blood can then move slowly in a small pouch of the heart and a clot may form. If that clot enters the circulation to the brain, it can block blood flow and cause an ischaemic stroke. Atrial fibrillation may come and go, so feeling a normal rhythm at one moment does not remove the need for an agreed prevention plan. Read about [Atrial Fibrillation](/conditions/atrial-fibrillation/) and [Stroke](/conditions/stroke/).

If atrial fibrillation is diagnosed, ask how your stroke risk is assessed and whether an anticoagulant is suitable. Take prescribed medicine as directed and tell the clinician about bleeding, falls, planned procedures or missed doses. Managing blood pressure, diabetes, smoking and other heart risks can also support prevention. Do not start aspirin or stop an anticoagulant on your own; the safest choice depends on your circumstances and other medicines.

Treat sudden facial drooping, arm or leg weakness, speech trouble, loss of vision, severe imbalance or new confusion as an emergency. Call emergency services immediately, even if the symptoms improve. A brief episode can still be a warning event requiring urgent assessment. Do not drive yourself, and note when the symptoms began if you can.

Ask how your risk is calculated, whether anticoagulation is recommended, what to do after a missed dose, and which bleeding symptoms or medication interactions need prompt advice.