Synopsis
Recognise atrial fibrillation, separate unstable from stable presentations, and make safe rate, rhythm and stroke-prevention decisions in a UK pathway.
- Suspect AF with an irregular pulse in a patient with palpitations, breathlessness, dizziness/syncope, chest discomfort, stroke or TIA; confirm with a 12-lead ECG.
- Typical ECG: no consistent sinus P waves and an irregularly irregular ventricular response; AF may be slow, controlled or rapid.
- If a 12-lead ECG misses suspected paroxysmal AF, NICE uses a 24-hour monitor when episodes are asymptomatic or less than 24 hours apart, and longer event/ECG monitoring when symptoms are more than 24 hours apart.
Key red flags
Shock (often SBP below 90 mmHg with hypoperfusion), syncope with severe or ongoing hypotension, myocardial ischaemia, severe heart failure with pulmonary oedema, or immediately post-ROSC.
Investigation priorities
Confirm AF, document rate/QRS/QT and identify instability, ischaemia, pre-excitation or another rhythm.
Management branches
Shock, syncope with severe/ongoing hypotension, myocardial ischaemia, pulmonary oedema/severe heart failure, or immediately post-ROSC.
- Call for expert/resuscitation help, perform ABCDE, attach monitor/defibrillator pads, obtain IV access and treat reversible causes.
- Use synchronised cardioversion. RCUK considers an initial shock at the defibrillator's maximum output reasonable for AF; make up to three synchronised attempts with escalation/local device settings.
Confirmed AF without life-threatening instability.
Key medicines
Atenolol IV/PO (licensed SmPC example of beta-blockade; not a mandatory NICE preference)Acute arrhythmia: 2.5 mg IV over 2.5 minutes; repeat at 5-minute intervals to response, maximum 10 mg. Alternative infusion: 0.15 mg/kg over 20 minutes. After control, 50-100 mg PO once daily is the cited maintenance regimen.
Verapamil IV5-10 mg by slow IV injection over at least 2 minutes with continuous ECG/BP observation; if necessary, a further 5 mg after 5-10 minutes.