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Syncope

It’s not the faint — it’s what caused it.

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Your objective: explain the approach, recognize important warning signs, then test your recall.

Abbreviations explained
ACS
Acute coronary syndrome
OMI
Occlusion myocardial infarction
ECG
Electrocardiogram
PE
Pulmonary embolism
POCUS
Point-of-care ultrasound
QTc
QT interval corrected for heart rate
LBBB
Left bundle branch block
RBBB
Right bundle branch block
hs-cTn
High-sensitivity cardiac troponin
CTA
Computed tomography angiography
ICU
Intensive care unit
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The jobIt’s not the faint — it’s what caused it.

  1. ECG for everyone.
  2. History for the cause: prodrome, posture, exertion, no warning.
  3. Exclude bleed, PE, and ectopic when the story fits.
  4. CSRS for disposition once an obvious serious cause is off the table (−3 to 0 home; ≥4 high-risk).

Syncope is transient global cerebral hypoperfusion.

Most cases are reflex (vasovagal) and benign; the ED job is to find the ~5–10% with cardiac or other lethal causes. ECG for everyone, a targeted history for the cause, and the Canadian Syncope Risk Score (CSRS) for disposition once an obvious serious cause has been excluded.

Lethal arrhythmia (long QT, WPW, Brugada, advanced block, VT) Critical

Key: Abnormal ECG, exertional or supine syncope, no prodrome, family history of sudden death.

Severe aortic stenosis / HCM Critical

Key: Exertional syncope with a pathologic murmur — echo.

High-risk PE Critical

Key: Syncope can be the only symptom; check VTE risks and RV strain.

Internal hemorrhage (AAA, GI bleed, ectopic) Critical

Key: Syncope with anemia, abdominal/back pain, or positive hCG.

SAH and other intracranial causes Critical

Key: Headache + collapse; “syncope with head injury” may be the other way around.

Carotid / subclavian steal Emergent

Key: Arm-exercise syncope with pulse/BP asymmetry.

Vasovagal / orthostatic / situational Common

Key: Prodrome (warmth, pallor, nausea) + trigger + upright posture — the reassuring triad.

Tick what your patient has — the banner updates as you go.

Circumstances

posture, triggers (blood, standing, micturition), exertion?

Prodrome vs no warning — cardiac causes often strike without prodrome

Palpitations, chest pain, dyspnea before the event

Family history of sudden death <40 y; known cardiomyopathy/channelopathy

QT-prolonging or hypotensive medications; alcohol

Orthostatic vitals; BP in both arms

Cardiac

murmurs (AS, HCM), rhythm, gallops

Volume status; rectal exam / visible melena if bleeding is suspected

Post-event neuro

seizure vs syncope (tongue biting, confusion, orientation)

Injury pattern consistent with abrupt collapse

Bedside

  • 12-lead ECG for everyone — QTc, blocks, delta waves, Brugada, ischemia, QRS axis/duration
  • Glucose; POCUS: RV strain, effusion, AAA, IVC

Labs

  • hCG in childbearing potential; heme screen if bleeding is suspected
  • Troponin when cardiac suspicion (a CSRS component if measured)
  • Electrolytes, CBC as indicated

Imaging / monitoring

  • CT head if injury or seizure is suspected; CTPA per PE pathway
  • ED rhythm monitoring; outpatient cardiac monitoring for selected intermediate-risk patients
Medication safety reminder

Use this as a first-pass prompt; verify all medications, doses, concentrations, contraindications, weight, pregnancy status, and local protocols before administration.

Check indication, allergy, route, renal/hepatic risk, interactions, monitoring, and local formulary.

Discharge

  • Reflex/vasovagal pattern, normal ECG, CSRS −3 to 0 (very low / low; 30-day serious outcome <1%) — hydration, counselling, GP follow-up.

Admit (telemetry) or shared decision

  • CSRS +1 to +3 (medium, ~8% 30-day serious outcomes): shared decision / brief observation. Abnormal ECG not clearly chronic; frail elderly living alone.

ICU / expedited cardiac workup

  • CSRS ≥4, documented arrhythmia, exertional syncope with murmur, PE with shock or strain plus biomarkers, positive troponin with ischemic features.

Use objective reassessment and the local pathway.

Before the next decision · reassess and hand over

Use these learning prompts with the presentation’s pathway. They are not discharge criteria.

  1. Reassess: compare symptoms, observations and examination with the initial assessment and response to treatment.
  2. Warning signs for Syncope:
    • Exertional syncope or syncope while supine
    • No prodrome / sudden collapse with facial injury
    • Abnormal ECG (QTc >480 ms per CSRS; blocks, pre-excitation, Brugada, ischemia)
    • Structural heart disease or family history of sudden death
    • Chest pain, dyspnea, or palpitations preceding the event
    • Ongoing blood loss or positive hCG
    • CSRS ≥4 (high / very high)
  3. Reconsider: check unresolved findings and alternative explanations, including the pitfalls below.
  4. Escalate: communicate deterioration, uncertainty or needs beyond the current setting.
  5. Plan the transition: identify outstanding results, responsibility for follow-up, patient understanding and specific return advice.
Review this presentation’s disposition pathway →Practice a handover →

Clinical Pearls

  • ECG for every syncope, no exceptions.
  • CSRS −3 to 0 (very low/low) can go home; +1 to +3 is shared decision; ≥4 is high-risk.
  • Syncope + facial injury means there was no warning — treat as cardiac until proven otherwise.
  • Exertional or supine syncope is cardiac until the opposite is proven.

Pitfalls

  • “Syncope + facial injury” is cardiac until proven otherwise (no time to protect the face).
  • Convulsive syncope mimics seizure — weigh the whole story.
  • A normal ED ECG does not exclude intermittent arrhythmia — history drives follow-up.
  • GI bleeding may be occult — look for melena in unexplained syncope.
  • Exertional syncope is cardiac until proven otherwise (rarely a post-exertional reflex faint — do not label it vasovagal in the ED).
  • CSRS ≥1 is medium, not high — do not automatically admit every +1.
PRACTICE REFRESHER

Rapid recall

Test your first action and the dangerous diagnoses before revealing the answer.

01 · First move

Before you scroll, what needs to happen first?

02 · Immediate threats

Name at least two diagnoses that cannot wait.

PRIVATE TO THIS DEVICE

Your learning note

Capture a weak point, a teaching pearl, or a question to take to your next shift.

Review schedule starts when marked reviewed
Chest PainSeizuresGI BleedingShockECG Guide

Selected guidance · source check 2026-09-07. These 1 source links support selected teaching points, not a complete review of this topic. Check population, setting and local protocol before applying a recommendation.

  • Rosen’s Emergency Medicine, 10th ed. (2023) — syncope
  • Canadian Syncope Risk Score: Thiruganasambandamoorthy et al., CMAJ 2016; multicenter validation JAMA Intern Med 2020
  • 2017 ACC/AHA/HRS and 2018 ESC Syncope Guidelines
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