---
title: Atrial fibrillation
description: What atrial fibrillation is, why it happens, how it is recognised and which treatment approaches exist.
type: disease
preset: atrial-fibrillation
aliases:
  - AF
  - AFib
sources:
  - tier: guideline
    org: esc
    title: 2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS
    year: 2024
    doi: 10.1093/eurheartj/ehae176
    url: https://doi.org/10.1093/eurheartj/ehae176
  - tier: guideline
    org: aha-acc
    title: 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation
    year: 2023
    doi: 10.1161/CIR.0000000000001193
    url: https://doi.org/10.1161/CIR.0000000000001193
  - tier: guideline
    org: minzdrav-rf
    title: Фибрилляция и трепетание предсердий
    year: 2025
    doi: 10.15829/1560-4071-2025-6668
    url: https://cr.minzdrav.gov.ru/view-cr/382_2
  - tier: guideline
    org: nice
    title: 'Atrial fibrillation: diagnosis and management (NG196)'
    year: 2021
    url: https://www.nice.org.uk/guidance/ng196
sources_checked: 2026-10-11
review: null
---

Atrial fibrillation (AF) is the most common rhythm disorder in the group of supraventricular tachyarrhythmias.<Cite n={3} /> In AF the atria are activated in an uncoordinated way and no longer contract effectively.<Cite n={1} />

<Diagram name="atrial-fibrillation">
  <p slot="normal">
    Normally the impulse is initiated by the sinoatrial node and conducted through the atria in
    smooth waves.<Cite n={2} />
  </p>
  <p slot="disease">
    In AF the electrical activity of the atria is chaotic: they are activated in an uncoordinated
    way and no longer contract effectively.<Cite n={[1, 3]} /> The ECG shows irregularly irregular
    RR intervals and no distinct P waves.<Cite n={[2, 3]} />
  </p>
</Diagram>

## Why it happens

<Patient>

Often no exact cause can be found.<Cite n={3} /> But AF is more common in people with high blood pressure, heart failure, diabetes, excess weight and pauses in breathing during sleep (sleep apnoea).<Cite n={[1, 3]} /> It is also linked to coronary heart disease and thyroid problems.<Cite n={3} /> An inactive lifestyle and drinking too much alcohol raise the risk.<Cite n={[1, 2]} />

</Patient>

<Student>

AF is characterised by chaotic atrial electrical activity at a rate of 350–700 per minute.<Cite n={3} /> It results in a loss of effective atrial contraction.<Cite n={1} /> In most cases the exact aetiology cannot be established; AF is associated with hypertension, coronary heart disease, heart failure, thyroid dysfunction, obesity, diabetes mellitus and obstructive sleep apnoea.<Cite n={3} /> Of the risk factors, hypertension has the highest attributable risk.<Cite n={2} /> The ACC/AHA guideline recognises AF as a progressive disease that requires different strategies at different stages.<Cite n={2} />

By temporal pattern, the ESC distinguishes paroxysmal AF (terminates spontaneously within 7 days or with the assistance of an intervention), persistent AF (episodes that are not self-terminating), long-standing persistent AF (continuous AF of at least 12 months' duration) and permanent AF (no further attempts to restore sinus rhythm are planned).<Cite n={1} />

</Student>

## Symptoms

<Patient>

The things people notice most often are a pounding or racing heartbeat (palpitations), shortness of breath, heaviness in the chest, poor sleep and tiring easily.<Cite n={[1, 3]} /> Sometimes there is dizziness or fainting.<Cite n={4} /> Some people have no symptoms at all, and the first sign of AF can be a stroke.<Cite n={3} />

</Patient>

<Student>

Symptoms are divided into cardiac-specific (palpitations) and non-specific (fatigue).<Cite n={1} /> Even in symptomatic patients some episodes are asymptomatic, and the presence or absence of symptoms is not related to the risk of stroke, systemic embolism or death.<Cite n={1} /> Symptom severity strongly correlates with quality of life.<Cite n={2} /> NICE advises checking the pulse in people with breathlessness, palpitations, syncope or dizziness, chest discomfort, or stroke or transient ischaemic attack.<Cite n={4} /> The most common non-fatal complication of AF is heart failure, and the next most common is ischaemic stroke; AF is also associated with increased mortality.<Cite n={1} />

</Student>

## How it is diagnosed

<Patient>

The doctor checks your pulse and, if it is irregular, records an electrocardiogram (ECG).<Cite n={4} /> If the episodes come and go, the ECG is recorded for longer, for example for a day.<Cite n={4} /> An ultrasound scan of the heart (echocardiogram) is usually done as well, to look at its structure and how it works.<Cite n={[1, 4]} /> The doctor then assesses the risk of stroke.<Cite n={[3, 4]} />

</Patient>

<Student>

ECG features of AF are irregularly irregular RR intervals and the absence of distinct P waves.<Cite n={[2, 3]} /> Diagnosis requires a recording of AF lasting 30 seconds or more on a single-lead or multiple-lead ECG device.<Cite n={[1, 3]} /> An automated device interpretation needs visual confirmation.<Cite n={2} /> In suspected paroxysmal AF not detected on a standard 12-lead ECG, NICE recommends a 24-hour ambulatory ECG monitor if asymptomatic episodes are suspected or symptomatic episodes are less than 24 hours apart; if symptomatic episodes are more than 24 hours apart, monitoring for a longer period.<Cite n={4} /> Transthoracic echocardiography is part of the initial work-up.<Cite n={1} />

Stroke risk is assessed with the CHA2DS2-VASc score, or with the CHA2DS2-VA score in the 2024 ESC guidelines.<Cite n={[1, 3, 4]} /> For bleeding risk, NICE recommends the ORBIT score.<Cite n={4} />

</Student>

## How it is treated

<Patient>

Treatment is built around a few goals: lowering the risk of stroke, easing symptoms and treating related conditions.<Cite n={1} /> To protect against stroke, medicines that reduce blood clotting are used.<Cite n={[3, 4]} /> To ease symptoms, the heart rate is slowed or the normal rhythm is restored.<Cite n={[1, 3]} /> Sometimes this is done with catheter ablation, a minimally invasive procedure that destroys the areas of heart tissue that trigger the arrhythmia.<Cite n={3} /> Lifestyle matters too: blood pressure, weight, alcohol and physical activity.<Cite n={[1, 2]} /> The doctor and the patient choose the way forward together.<Cite n={[1, 2]} />

</Patient>

<Student>

The 2024 ESC guidelines describe management as AF-CARE: [C] comorbidity and risk factor management, [A] avoid stroke and thromboembolism, [R] reduce symptoms by rate and rhythm control, [E] evaluation and dynamic reassessment.<Cite n={1} /> The ACC/AHA guideline recognises lifestyle and risk factor modification as a pillar of AF management.<Cite n={2} />

The decision on anticoagulation is based on the assessed thromboembolic risk.<Cite n={[2, 3]} /> NICE recommends offering a direct-acting oral anticoagulant to people with AF and a CHA2DS2-VASc score of 2 or above, taking into account the risk of bleeding, and states that anticoagulation should not be withheld solely because of a person's age or their risk of falls.<Cite n={4} /> Rate control uses beta-blockers, rate-limiting (non-dihydropyridine) calcium-channel blockers (diltiazem, verapamil) and digoxin; NICE recommends rate control as the first-line strategy, except in certain groups of patients.<Cite n={[1, 4]} /> Rhythm control includes pharmacological and electrical cardioversion and catheter ablation.<Cite n={[3, 4]} /> The ACC/AHA guideline gives catheter ablation a Class 1 indication as first-line therapy in selected patients.<Cite n={2} /> In life-threatening haemodynamic instability caused by new-onset AF, NICE recommends emergency electrical cardioversion without delaying to achieve anticoagulation.<Cite n={4} /> The strategy is chosen through shared decision-making with the patient.<Cite n={[1, 2]} />

</Student>

## When to call an ambulance

Call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK) if there are signs of a stroke: AF can first show itself as a stroke or a transient ischaemic attack.<Cite n={3} /> As with any heart condition, call an ambulance for fainting, chest pain or severe shortness of breath: this is the site's general safety rule, repeated at the bottom of every page. If AF causes a life-threatening circulatory problem (haemodynamic instability), doctors restore the rhythm as an emergency.<Cite n={4} />

<Quiz />