Syncope 💫
UK on-call guide to syncope and transient loss of consciousness in adults: NICE CG109 first assessment, ECG red flags, risk stratification, and when to follow your Trust admission pathway.
📌 Initial assessment
- If there is injury or incomplete recovery of consciousness, treat urgently using clinical judgement.
- Take witness-based before/during/after history; phone absent witnesses where possible.
- Record all CG109 event fields: circumstances, posture, prodrome, appearance/colour, movements and duration, tongue bite (side vs tip), injury site/severity, event duration to recovery, post-event confusion, unilateral weakness in recovery.
- Assume TLoC if uncertain; if not TLoC, manage the confirmed alternative pathway (for example falls).
🧾 History, exam, and ECG
- Record previous TLoC frequency, cardiac/family history, contributing medicines, vitals (repeat if needed), lying/standing BP when appropriate, and cardio-neuro signs.
- Record a 12-lead ECG using automated interpretation.
- ECG red flags: conduction abnormality (including any heart block), long/short QT, ST/T-wave abnormalities.
- Expert manual review for: persistent inappropriate bradycardia, ventricular arrhythmia/ectopy, long QT >450 ms or short QT <350 ms, Brugada, WPW, LVH/RVH, abnormal T-wave inversion, pathological Q waves, sustained atrial arrhythmia, paced rhythm.
- Order targeted tests only if a concurrent cause is suspected (for example glucose for hypoglycaemia, haemoglobin for bleeding/anaemia).
🚨 Urgent cardiovascular referral (within 24 hours)
- If TLoC is due to a condition needing immediate action, escalate immediately.
- Urgent 24-hour cardiovascular referral for TLoC with any of: ECG abnormality, heart failure signs/history, exertional TLoC, family history of sudden death <40 or inherited cardiac disease, new unexplained breathlessness, or heart murmur.
- Consider 24-hour referral for age >65 with TLoC and no prodrome.
✅ Diagnoses that usually need no immediate further management
- Uncomplicated faint (vasovagal): no competing diagnosis and classic 3 Ps (posture, provoking factor, prodrome). Brief seizure-like activity can still occur in simple faints.
- Situational syncope: no competing diagnosis and clear reproducible trigger (micturition strain, cough, swallowing).
- If uncomplicated and no clinical/social concern: no immediate further management. If seen outside GP, ensure GP receives report and ECG; if no ECG done, arrange one within 3 days.
- If presenting via ambulance and the diagnosis is not clearly uncomplicated faint or situational syncope, convey to ED.
🧷 Postural hypotension
- Suspect when history is typical and no competing diagnosis is found.
- Measure/manage per NICE hypertension guidance.
- If symptoms suggest postural hypotension but BP criteria are not met, refer for specialist cardiovascular assessment.
🧠 Suspected epilepsy (specialist within 2 weeks)
- Refer if any strong seizure features: tongue bite, head turning, witnessed abnormal behaviour with amnesia, unusual posturing, prolonged limb jerking, post-event confusion, déjà vu/jamais vu prodrome.
- Features arguing against epilepsy: symptoms prevented by sitting/lying, pre-event sweating, prolonged standing trigger, pallor during event.
- Do not routinely use EEG in the investigation of TLoC.
📨 Who gets specialist cardiovascular assessment
- Refer all TLoC patients except those with firm diagnoses of uncomplicated faint, situational syncope, postural hypotension, or presentations strongly suggestive of epilepsy.
- At specialist review, follow your local pathway to define likely mechanism (structural, arrhythmic, neurally mediated, or unexplained) and choose targeted tests.
🧪 Diagnostic pathway by mechanism
- Exercise syncope: separate during-exercise (arrhythmic concern) from post-exercise (often vasovagal). During-exercise episodes need urgent exercise testing within 7 days unless contraindicated, and no further exercise until reviewed.
- Suspected arrhythmic syncope: offer ambulatory ECG first-line; do not use tilt test first-line.
- Choose ambulatory ECG by frequency: several/week -> Holter up to 48h then external recorder if nondiagnostic; every 1-2 weeks -> external recorder then implantable if events missed; <every 2 weeks -> implantable recorder (Holter usually only if conduction abnormality on 12-lead ECG).
- Do not offer tilt testing for vasovagal syncope already diagnosed on initial assessment.
- For recurrent vasovagal episodes affecting quality of life or causing injury risk, consider tilt testing only to detect severe cardioinhibitory response (usually asystole).
- If carotid sinus syncope is suspected, or unexplained syncope age >=60, offer carotid sinus massage first-line in a controlled setting with ECG and resuscitation equipment.
- Diagnose carotid sinus syncope only if massage reproduces syncope with marked bradycardia/asystole and/or hypotension; do not diagnose from asymptomatic transient changes.
- For unexplained syncope (including after negative carotid massage where relevant), offer ambulatory ECG and do not do tilt testing before ambulatory ECG.
- Implantable recorder requirements: dual patient-triggered and automatic detection modes, patient/family training, and prompt post-event device interrogation.
❓ If diagnosis remains uncertain
- Consider PNES or psychogenic pseudosyncope if events change over time, are unusually prolonged, or occur with multiple unexplained physical symptoms; refer for neurological assessment if suspected.
- Ask patients/witnesses to capture future events (video or detailed witness account) when diagnosis is unclear.
- If still uncertain or not responding to treatment, reconsider alternative and mixed mechanisms (for example ictal arrhythmia).
ℹ️ Information, driving, and safety
- Discuss likely cause, test benefits/risks, results, reasons for further tests, and residual diagnostic uncertainty.
- Give DVLA advice at first presentation; advise no driving while awaiting specialist assessment; after specialist review, advise reporting obligations per DVLA guidance.
- Give workplace safety advice and required modifications.
- For uncomplicated/situational syncope: explain mechanism, trigger avoidance, symptom diary if triggers unclear, reassure good prognosis, and advise GP review if episodes recur or change.
- For postural hypotension: review mechanism, contributory medicines, prognosis, treatment options, and what to do if events recur.
- While waiting for specialist cardiovascular or neurological assessment: provide clear action plan for recurrent events and activity modification (including no driving where applicable).
External resources
Note Template
Ready-to-use clinical note structure
🕒 08 / 10 / 2026 — 16:02 ATRP re: syncope / blackout / T-LOC Patient: [age] [sex] Admission Dx: [reason for admission] PMHx: [IHD, CCF, epilepsy, Parkinson's, structural heart disease, previous syncopes] 🧾 Event History: • Position/activity prior: [standing / seated / supine / exertional] • Situation: [3Ps - Provoking factor, Prodrome, Postural] • Prodrome: [dizziness / nausea / sweating / palpitations / none / <10sec] • Witness account: [yes/no] - [description of event] • Post-event: [rapid recovery / confusion / injury] 🧾 Background: • Previous syncopes: [frequency / timing / similar characteristics] • Medications: [antihypertensives / diuretics / antiarrhythmics / others] • Family Hx: [blackouts / channelopathy / sudden cardiac death] • Social: [functional status in elderly / driving status] 🩺 Exam: • Vitals: HR __ BP __ (lying/standing) __ RR __ Temp __ SpO₂ __ • Cardiorespiratory: [normal / murmur / JVP / oedema / creps] • Neurological: [normal / focal signs] • Other: [as dictated by history] 🧪 Investigations: • ECG: [normal / abnormal - specify findings] • Lying-standing BP: [if postural symptoms] • β-HCG: [if female of child-bearing age] • BSL: __ • Other: [as indicated] 🚩 Risk Assessment: • Red flags: [supine/exertional syncope / palpitations / chest pain / structural heart disease / abnormal ECG / other] • Orange flags: [seated syncope / sudden drop / FHx channelopathy] • Green flags: [3Ps / situational triggers / recurrent similar episodes] 📋 Impression: Likely type: [vasovagal / situational / orthostatic / cardiogenic / secondary / unclear] Risk category: [high / moderate / low] 📌 Plan: • [If high risk: Admit for telemetry, intensive workup, urgent treatment] • [If moderate risk: Consider admission or Syncope Unit referral] • [If low risk: Reassurance, education, trigger avoidance. Discharge if well] • [Device interrogation if PPM/ICD] • [Fitness to drive assessment if discharging] • [Follow-up: GP / Syncope Unit / Cardiology / other] 👤 [Your Name], [Role] IMC: _______
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