--- title: "Atrial fibrillation, stroke risk and treatment options" description: "What atrial fibrillation is, how stroke risk is assessed, when anticoagulation is used, and how rate and rhythm control strategies compare." url: "https://www.drmartins.org/conditions/atrial-fibrillation/" author: "Dr Joao Martins" medical_reviewer: "Dr Joao Martins" review_status: "approved" date_published: "2026-09-01" date_modified: "2026-09-01" --- # Atrial fibrillation, stroke risk and treatment options Atrial fibrillation is an irregular and often fast heart rhythm caused by disorganised electrical activity in the upper chambers of the heart. Some people feel palpitations, breathlessness or fatigue; others have no symptoms at all and it is found incidentally. Its main significance is an increased risk of stroke, which can be assessed individually and substantially reduced with anticoagulation where appropriate. Treatment then addresses the rhythm itself, either by controlling the heart rate or by attempting to restore and maintain a normal rhythm. ## When to seek urgent help Call 999 if you have chest pain, severe breathlessness, or you faint. Seek urgent medical advice if you develop sudden weakness or numbness on one side, difficulty speaking, or loss of vision, which may indicate a stroke. ## Key facts - Atrial fibrillation becomes more common with age and can be present without any symptoms. - Stroke risk is assessed individually, taking account of age, sex, blood pressure, diabetes, heart failure and previous stroke. - Anticoagulation substantially reduces stroke risk; aspirin is not an adequate substitute for this purpose. - Rate control and rhythm control are both legitimate strategies, chosen according to symptoms and circumstances. - Treating contributing factors such as high blood pressure, alcohol intake, obesity and sleep apnoea affects how well any treatment works. ## What is happening in the heart In a normal heartbeat, electrical activity begins in one place in the upper chambers and spreads in an orderly way. In atrial fibrillation, that activity becomes disorganised: the upper chambers quiver rather than contract properly, and the lower chambers respond irregularly, often quickly. The pattern varies between people. It may come and go in episodes lasting minutes to days, which resolve on their own; it may persist until treatment restores a normal rhythm; or it may become permanent, where a decision has been taken not to attempt restoration. These distinctions influence which treatments are appropriate. ## How it is found Some people notice an irregular, fast or fluttering heartbeat, breathlessness on exertion, reduced exercise tolerance or fatigue. Many notice nothing, and the diagnosis is made when a pulse is checked, when blood pressure is measured with a device that flags irregularity, or during an ECG performed for another reason. Confirmation requires an ECG recording during the rhythm. Where episodes are intermittent, ambulatory monitoring over a period of days or longer may be needed. An echocardiogram is usually arranged to assess the heart chambers and valves, and blood tests including thyroid function are routine. ## Stroke risk comes first The single most important consequence of atrial fibrillation is an increased risk of stroke, because blood that is not moving normally through the upper chambers can form clots. That risk is not the same for everyone, and it is assessed using an established scoring system that takes account of age, sex, blood pressure, diabetes, heart failure, vascular disease and any previous stroke. Where the assessed risk is sufficient, anticoagulation is recommended. This is a genuine decision, not an automatic one: the reduction in stroke risk is weighed against bleeding risk, and both are discussed openly. What is clear from the evidence is that aspirin does not provide adequate protection against stroke in atrial fibrillation and should not be used for that purpose. ## Rate control and rhythm control Two broad strategies exist, and they are not in competition; the choice depends on symptoms, how long the rhythm has been present, age and other conditions. Rate control accepts the irregular rhythm and uses medication to keep the heart rate in a reasonable range. Rhythm control aims to restore and maintain a normal rhythm, using medication, an electrical cardioversion, or catheter ablation. It is more often chosen where symptoms are troublesome despite adequate rate control, where the rhythm is of recent onset, or in younger patients. Anticoagulation decisions are made on the basis of assessed stroke risk and are not automatically stopped because a normal rhythm has been restored. ## What you can influence High blood pressure, excess alcohol, obesity, poorly controlled diabetes, thyroid disorders and obstructive sleep apnoea all make atrial fibrillation more likely to occur and harder to control. Addressing these improves how well any chosen treatment works, and is a genuine part of management rather than general advice. ## Sources - [Atrial fibrillation](https://www.nhs.uk/conditions/atrial-fibrillation/) — NHS - [Atrial fibrillation - diagnosis and management (NG196)](https://www.nice.org.uk/guidance/ng196) — NICE --- General information only. It does not replace individual medical advice, diagnosis or emergency care. In an emergency call 999.