Suspect new-onset AF if the patient has an irregularly irregular pulse with or without any one of: palpitations (the cardinal symptom); dyspnoea; chest pain; fatigue; dizziness; polyuria; syncope.
Perform manual pulse palpation and conduct an immediate 12-lead ECG.
Regardless of the duration of onset of the patient’s arrhythmia, do not delay emergency synchronised direct current (DC) cardioversion in the following groups as their condition may be life-threatening: features of haemodynamic instability; symptoms of acute myocardial ischaemia; suspected or confirmed serious precipitating illness requiring hospital care; AF alongside a pre-excitation syndrome such as Wolff-Parkinson-White syndrome; signs or symptoms of acute stroke.
Urgently admit any patient who is haemodynamically compromised to an acute medical unit. Call for anaesthetic support to sedate the patient before DC cardioversion. In patients not already on therapeutic anticoagulation, immediately start anticoagulation pre-cardioversion. Seek senior and/or specialist review; this should not delay urgent DC cardioversion.
Follow the integrated Atrial fibrillation Better Care (ABC) pathway for holistic management of any patient with AF: A - Anticoagulation/Avoid stroke; B - Better symptom management; C - Cardiovascular and comorbidity optimisation (including lifestyle changes).
In all patients, prioritise calculating stroke risk using the CHA2DS2-VASc score.
If you are considering anticoagulation, use the ORBIT score, if available, or the HAS-BLED score if not, to assess the risk of a major bleed, identify (and subsequently manage) modifiable risk factors for bleeding, and flag the ‘high bleeding risk’ patients for early review and follow-up.
Start rate control in any patient without life-threatening haemodynamic instability while initially assessing the patient. If the patient still has symptoms after their rate has been controlled or rate control has not been achieved, consider rhythm control.
Identify unhealthy lifestyle factors and give the patient advice on these to help prevent recurrence. Work with the patient to identify strategies for comprehensive risk-factor modification and interventions targeting underlying conditions that may apply.
Atrial fibrillation (AF) is a supraventricular tachyarrhythmia with uncoordinated atrial electrical activation and consequently ineffective atrial contraction. Electrocardiographic characteristics include:
Irregularly irregular R-R intervals (where atrioventricular conduction is not impaired)
Absence of distinct repeating P waves
Irregular atrial activations.
New-onset AF is defined as a new onset or a first detectable episode of AF, whether symptomatic or not. This topic covers symptomatic new-onset AF in the non-valvular and non-surgical settings. Paroxysmal and asymptomatic new-onset AF are covered in our topic Chronic atrial fibrillation.
History and exam
Key diagnostic factors
- irregular pulse rate
- risk factors
Other diagnostic factors
- symptomatic hypotension
- chest pain/tightness/discomfort
- cognitive impairment
- abnormal breath sounds
- additional heart sounds
- elevated jugular venous pressure
- evidence of stroke
- pre-syncope and syncope
- increasing age
- heart failure
- diabetes mellitus
- obstructive sleep apnoea
- coronary artery disease
- valve disease
- other cardiac disease
- regular, heavy alcohol consumption
- cardiac or thoracic surgery
- other atrial arrhythmias
- previous stroke/transient ischaemic attack
- athletic levels of physical activity
1st investigations to order
- clotting profile
- electrolytes, urea, and creatinine
- thyroid function
- transthoracic echocardiography (TTE)
Investigations to consider
- cardiac troponin
- B-natriuretic peptide (BNP)/N-terminal prohormone B-natriuretic peptide (NT-pro-BNP)
- erythrocyte sedimentation rate
- transoesophageal echocardiogram (TOE)
- inpatient telemetry or 24-hour holter monitor
- coronary angiography (CT or conventional) or stress testing
- late gadolinium contrast-enhanced cardiac MR (CMR)
- brain CT
- brain MRI
- computed tomographic pulmonary angiography (CTPA)
haemodynamically stable: onset <48 hours
haemodynamically stable: onset ≥48 hours or uncertain
Resham Baruah, MBBS, BSc, MRCP, PhD
Chelsea and Westminster Hospital and the Royal Brompton and Harefield NHS Trust
RB has received honorarium/speaker fees from Novartis and Boehringer Ingleheim.
Adam D. Hartley, MBBS, BSc, MRCP
Wellcome Trust Clinical Research Fellow
Imperial College London
Specialist Registrar in Cardiology
Imperial College Healthcare NHS Trust
ADH declares that he has no competing interests.
BMJ Best Practice would like to gratefully acknowledge the previous team of expert contributors, whose work is retained in parts of the content:
Arti N. Shah, MS, MD
Elmhurst Hospital Center
Assistant Professor of Medicine
Mount Sinai School of Medicine
ANS is an author of a number of references cited in this topic.
Bharat K. Kantharia MD, FRCP, FAHA, FACC, FESC, FHRS
Cardiovascular and Heart Rhythm Consultant
Attending and Consultant Cardiac Electrophysiologist
Mount Sinai Hospitals
New York Methodist Hospital
West Houston Medical Center
Memorial Hermann Hospital
BKK is an author of a number of references cited in this topic.
Gregory Lip, MD, FRCP, DFM, FACC, FESC, FEHRA
Price-Evans Professor of Cardiovascular Medicine
University of Liverpool
National Institute for Health Research
Faculty of Medicine
GL is a consultant for Bayer/Janssen, BMS/Pfizer, Medtronic, Boehringer Ingelheim, Novartis, Verseon, and Daiichi-Sankyo. He is a speaker for Bayer, BMS/Pfizer, Medtronic, Boehringer Ingelheim, and Daiichi-Sankyo. No fees are directly received personally. GL is an author of a number of references cited in this topic.
Lead Section Editor, BMJ Best Practice
TAO declares that she has no competing interests.
Lead Section Editor, BMJ Best Practice
RW declares that she has no competing interests.
Head of Editorial, BMJ Knowledge Centre
JH declares that she has no competing interests.
Comorbidities Editor, BMJ Best Practice
JC declares that she has no competing interests.
Drug Editor, BMJ Best Practice
AM declares that he has no competing interests.
Consultant Cardiologist and Electrophysiologist
Royal Brompton and Harefield Hospitals
SH was a Section Editor, BMJ Best Practice. SH declares that he has no competing interests.
- Atrial flutter
- Wolff-Parkinson-White syndrome
- Atrial tachycardia
- Atrial fibrillation: diagnosis and management
- 2020 ESC guidelines for the management of atrial fibrillation developed in collaboration with EACTS
Atrial Fibrillation CHA(2)DS(2)-VASc Score for Stroke Risk
ORBIT Bleeding Risk ScoreMore Calculators
How to perform an ECG animated demonstrationMore videos
Atrial fibrillation: what is it?
Atrial fibrillation: what treatments work?More Patient leaflets
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