Syncope: Risk Stratification & Workup

Syncope (transient loss of consciousness with rapid, complete recovery) is usually benign, but sometimes it’s a harbinger of arrhythmia or structural heart disease. Use this stepwise approach to separate low-riskfrom high-risk patients and choose tests that actually change management.

Mechanisms (think buckets)

• Reflex/vasovagal (neurally mediated): prodrome (nausea, warmth, tunnel vision), triggers (pain, standing, emotional stress).
• Orthostatic hypotension: volume loss, meds (diuretics, antihypertensives), autonomic failure; symptoms after standing.
• Cardiac: arrhythmic (brady/tachy), structural (AS, HCM, ischemia), pulmonary embolism.
• Not syncope: seizure (post-ictal confusion, tongue laceration), psychogenic pseudosyncope, metabolic (hypoglycemia).

Initial Assessment (bedside in minutes)

• Vitals including orthostatics (supine → standing BP/HR if safe).
• 12-lead ECG for conduction disease, ischemia, pre-excitation, QTc abnormalities.
• Focused history: prodrome, posture, exertion, chest pain/dyspnea, palpitations, trauma, meds (QT-prolonging), alcohol/substances, family history of sudden cardiac death.
• Point tests as indicated: capillary glucose, pregnancy test, Hb/Hct if bleeding suspected; troponin if ischemia suspected—don’t shotgun labs.

High-Risk Features (consider admission/urgent workup)

• Exertional syncope, syncope while supine, or without prodrome.
• Abnormal ECG: AV block, wide QRS, Brugada pattern, WPW, pathologic Q waves, QTc prolongation.
• Known structural heart disease or heart failure, or new murmur (possible aortic stenosis/HCM).
• Chest pain, dyspnea, or signs of PE/ACS; hypotension, anemia, GI bleed.
• Persistent abnormal vitals, new neurologic deficit, or serious injury from the event.

Low-Risk Features (outpatient pathway reasonable)

• Classic vasovagal trigger with prodrome, quick full recovery.
• Normal exam and ECG; no concerning comorbidities or red flags.
• Single brief episode; reliable follow-up available.

Targeted Diagnostics (don’t overtest)

• Rhythm monitoring: Holter (24–48h) for frequent events; patch/event monitor (1–2+ weeks) if intermittent; implantable loop recorder for rare, unexplained syncope with high suspicion of arrhythmia.
• Echocardiography: if abnormal ECG, murmur, or suspected structural disease.
• Exercise testing: exertional syncope or suspected ischemia/arrhythmia provoked by activity.
• Tilt-table testing: recurrent unexplained syncope with suspected reflex mechanism; also helps in orthostatic hypotension evaluation.
• Neuroimaging/EEG: not routine; reserve for focal neurologic findings, head trauma, or features strongly suggesting seizure.

Management by Mechanism

• Reflex/vasovagal: education, hydration, salt (if appropriate), physical counter-pressure maneuvers, avoid triggers; consider graded conditioning. Meds or pacing are rare, reserved for refractory, documented cardioinhibitory cases.
• Orthostatic: review meds (diuretics, vasodilators), treat volume depletion and anemia, slow position changes, compression stockings; consider pharmacologic support in refractory autonomic failure per specialist.
• Cardiac: treat underlying cause—revascularization for ischemia, valve intervention for severe AS, ablation or devices for arrhythmias per electrophysiology.

Disposition Algorithm (one-page logic)

1. Bedside triage: ABCs → vitals/orthostatics → ECG.
2. Any high-risk feature? → monitored setting and targeted inpatient workup.
3. No high-risk features → outpatient plan with education and appropriate testing (monitor, echo, tilt) based on suspicion.
4. Address drivers (meds, dehydration, anemia) and safety counseling (driving, heights, operating machinery) until diagnosis clarified.

Patient FAQs

“Do I need a head CT?” Not if you have a normal neuro exam and a typical faint—imaging rarely helps without focal findings or trauma.

“Can stress cause this?” Yes—vasovagal syncope is often triggered by stress or pain and typically improves with counter-pressure training and hydration.

References & Notes

This pathway mirrors common emergency and cardiology practice: ECG for all, orthostatics when safe, focus on red flags, and use rhythm monitoring/echo selectively. Local protocols vary—follow institutional guidance. Educational only.