Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Escalate
Admit or urgently assess syncope with an abnormal ECG, structural heart disease, exertional or supine occurrence, injury, heart failure, family history of young sudden death, or ongoing unstable arrhythmia; ambulatory monitoring must not replace acute telemetry.
Synopsis
Match ECG-monitor duration and technology to symptom frequency so clinically important intermittent arrhythmias are captured and correlated with events.
Choose the monitor from event frequency: short continuous recording for daily events, longer external recording for less frequent events and an implantable recorder for infrequent unexplained syncope.
NICE recommends 24-hour ambulatory ECG when suspected paroxysmal AF episodes are less than 24 hours apart or asymptomatic episodes are suspected.
For suspected paroxysmal AF with episodes more than 24 hours apart, use longer ambulatory ECG, event recording or another appropriate ECG technology.
Key red flags
High-risk bradyarrhythmia
Symptomatic pauses, high-grade AV block or profound bradycardia require prompt specialist assessment and may lead to pacing.
Investigation priorities
01
24–48-hour continuous ECGFirst step
Capture daily palpitations, frequent presyncope or suspected frequent/asymptomatic AF.
Management branches
Preferred routeIntermittent palpitations
No diagnostic rhythm on a resting ECG
Clarify frequency, duration, regularity, triggers and associated syncope or chest pain; obtain baseline ECG and relevant blood tests.
Select continuous 24-hour monitoring for daily or very frequent episodes and longer patch or event recording for less frequent episodes.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.