Atrial Fibrillation

Last updated 27th March 2025

Epidemiology

AF is the most common arrhythmia, with year on year increase in hospital admissions.
Prevalence increases steeply with age from < 1% under 60 years, to 5% over 65 years and 10% over 75 years.
May be present in up to 50% in patients with severe heart failure.

Causes of AF

Cardiac	Non-Cardiac
Ischaemic Heart Disease	Thyrotoxicosis
HT esp if LVH	Binge drinking/Caffeine abuse
Congestive HF	COPD/Emphysema
Valvular heart disease esp. MS and MR	PE
Myo/Pericarditis	Idiopathic (lone AF)
Sino atrial disease (as an escape rhythm)	Acute illness (hyperadrenergic state)
Other arrhythmias eg atrial flutter	Cancers involving pericardium*

*Especially primary lung cancer involving the pleura and pericardium, and cancers such as breast cancer and malignant melanoma metastasising to the pericardium. In addition, patients who have had radiotherapy to the mediastinum for cancers such as Hodgkin’s and non-Hodgkin’s lymphoma are prone to AF.

Clinical Presentation

Commonly causes palpitations, shortness of breath, fatigue, chest pain, dizziness, and symptoms associated with stroke.
AF can cause a tachycardia-induced cardiomyopathy resulting in symptoms of HF.
In patients with a rapid ventricular response, cerebral hypoperfusion can result in presyncope or syncope.
Up to 20% of patients with AF may be asymptomatic.

Recognition

Most patients will have a fast and totally irregular (irregularly irregular) pulse
An apparently regular pulse does not exclude AF. It can be extremely difficult to appreciate irregularity if the pulse rate is very rapid or very slow. Slow AF may occur in patients with very poor AV nodal conduction due to intrinsic AV nodal disease or AV nodal blocking drugs.
An apparently irregular pulse does not always indicate AF. Other causes of irregular pulse are frequent premature atrial and/or ventricular complexes in the presence of sinus rhythm, multifocal atrial tachycardia, or atrial flutter with variable AV block. It is therefore necessary to confirm the rhythm with an ECG.

Diagnosis

An ECG is usually confirmatory. P waves are absent and are replaced by rapid fibrillatory waves, which vary in size, shape, and timing, leading to an irregular ventricular response when AV conduction is intact.
In people with suspected paroxysmal AF undetected by standard ECG:
- use a 24-hour ambulatory ECG in those with suspected asymptomatic episodes or symptomatic episodes less than 24 hours apart
- use an event recorder ECG in those with symptomatic episodes more than 24 hours apart.

Role of Echocardiography and Other Tests

Perform transthoracic echocardiography (TTE) in people with AF when:
- a rhythm-control strategy that includes cardioversion is being considered
- there is a high risk or a suspicion of underlying heart disease eg heart failure or murmur that might influence subsequent choice of drug therapy
- refinement of clinical risk stratification for antithrombotic therapy is needed
Do not routinely perform TTE solely for the purpose of further stroke risk stratification when the need to anticoagulate has already been agreed.
Perform transoesophageal echocardiography (TOE) in people with AF when:
- TTE demonstrates an abnormality (such as valvular heart disease) that warrants further specific assessment
- TTE is technically difficult and/or of questionable quality and where there is a need to exclude cardiac abnormalities
- TOE-guided cardioversion is being considered.
All patients should have routine FBC, U&E, BG, LFTs and TFTs

Management

The goals of treatment are to alleviate symptoms, improve quality of life, prevent a tachycardia-induced cardiomyopathy and reduce thromboembolic events.
Management can be summarised as ‘Rate control, Rhythm control and Antithrombotic therapy’, each of which are dealt with in detail in subsequent sections