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.
Syncope
Cardiology · UK scope · Sources checked 25 Aug 2026 · Clinical review pending
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Escalate
Incomplete recovery, significant injury, ongoing haemodynamic/neurological abnormality, exertional or supine syncope, an abnormal ECG or suspected arrhythmia needs urgent assessment. NICE red flags require specialist cardiovascular assessment reviewed and prioritised within 24 hours.
Synopsis
Distinguish uncomplicated faint from cardiac syncope, seizure and postural hypotension, then order monitoring according to event frequency and act on NICE red flags.
Syncope is transient loss of consciousness from cerebral hypoperfusion, with rapid onset, short duration and spontaneous complete recovery; confirm that true TLoC occurred before naming the cause.
Get the witness story: posture, trigger/prodrome, colour, eyes, movements and their duration, tongue-bite site, injury, event duration, recovery confusion and focal weakness.
Every suspected TLoC needs vital signs, cardiovascular/neurological examination, medication review and a 12-lead ECG unless an immediately life-threatening cause dictates treatment first.
NICE cardiac red flags: abnormal ECG, heart failure, TLoC during exertion, family sudden cardiac death under 40/inherited disease, new unexplained breathlessness or murmur; consider the same 24-hour route if over 65 with no prodrome.
The three Ps support uncomplicated vasovagal faint: posture (prolonged standing), provoking factor (pain/procedure) and prodrome (warmth/sweating). Brief jerks can occur in syncope.
Seizure markers include lateral tongue bite, head turning, witnessed abnormal behaviour with amnesia, unusual posturing, prolonged jerking, post-event confusion or déjà/jamais vu; do not routinely order EEG for undifferentiated TLoC.
Measure postural BP supine then after standing at least 1 minute; a fall of at least 20 mmHg systolic or 10 mmHg diastolic is significant under current NICE guidance.
For suspected arrhythmic syncope, NICE chooses ambulatory ECG by event frequency and says not to use tilt testing first.
Syncope during exercise needs exercise testing within 7 days unless contraindicated, and no exercise until assessed; post-exercise syncope is more often reflex.
NICE says all people with TLoC must not drive while waiting for specialist assessment; apply current DVLA rules after diagnosis.
Key red flags
Cardiac red flags
Abnormal ECG, heart failure, TLoC during exertion, family sudden cardiac death under 40 or inherited cardiac condition, new unexplained breathlessness, or murmur; also consider urgent referral when older than 65 with no prodrome.
High-risk event context
Syncope while supine/sitting, during exercise, with sudden palpitations or chest pain, major injury, known structural disease, persistent hypotension or abnormal examination raises arrhythmic/structural concern even if recovery is complete.
Investigation priorities
01
Patient and witness historyFirst step
Reconstruct before, during and after the event and confirm genuine TLoC.
Management branches
ImmediateUnrecovered, injured or unstable patient
Incomplete recovery, serious injury, persistent ABC/neurological abnormality or an active arrhythmia.
Manage ABCDE and the immediate cause; check glucose when relevant and treat cardiac arrest/arrhythmia using the RCUK pathway.
Do not label as a simple faint until recovery, examination and ECG support it.
Escalate suspected ACS, PE, aortic stenosis/HCM, haemorrhage, stroke or toxic/metabolic cause through its emergency pathway.
Key medicines
Midodrine (licensed specialist option)2.5 mg PO three times daily initially; increase at weekly intervals according to supine/standing BP up to 10 mg three times daily. Give during daytime; last dose at least 4 hours before bed.Check supine/standing BP and renal/hepatic function; stop if supine hypertension persists despite dose reduction. Contraindicated in acute/severe renal impairment (CrCl under 30 in cited SmPC), hypertension, serious vascular disease, urinary retention/serious prostate disorder, phaeochromocytoma, hyperthyroidism and narrow-angle glaucoma.
Sources and review status6 sources · checked 25 Aug 2026 · clinical review pending+
Sources
Sources and review status
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 25 Aug 2026; clinical approval remains outstanding.