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2018 ESC Guidelines for Syncope

Diagnosis and Management of Transient Loss of Consciousness

Published: European Heart Journal (2018) 39, pp. 1883–1948
DOI: 10.1093/eurheartj/ehy037
Task Force: European Society of Cardiology (ESC) with special contribution of EHRA
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Summary Classification Initial Evaluation Risk Stratification Reflex Syncope Orthostatic Hypotension Cardiac Syncope Diagnostic Testing Monitoring Key Figures Do's & Don'ts Calculators

Summary

The 2018 ESC Guidelines for the diagnosis and management of syncope provide a comprehensive framework for evaluating patients with transient loss of consciousness. Syncope is defined as a transient loss of consciousness (TLOC) with loss of postural tone, caused by transient global cerebral hypoperfusion. The diagnostic approach is based on initial evaluation combining history, physical examination, and risk stratification, with subsequent targeted investigations guided by clinical findings.

Key Changes from 2009 Guidelines

  • Enhanced role of syncope units as cost-effective diagnostic and risk stratification tools
  • Simplified risk stratification with clear high-risk and low-risk features
  • Refined criteria for electrocardiographic monitoring in unexplained syncope
  • Updated pacing recommendations for reflex syncope and orthostatic hypotension
  • New section on syncope in special populations and psychogenic pseudosyncope
  • Emphasis on physical counter-pressure manoeuvres in reflex syncope management

Classification of Syncope

Syncope is classified into three main categories based on pathophysiological mechanisms. The classification distinguishes true syncope from non-syncopal transient loss of consciousness including psychogenic pseudosyncope, seizures, and stroke.

Main Categories

1. Reflex (Neurally-Mediated) Syncope

  • Vasovagal syncope: Most common type, triggered by emotional stress, pain, or prolonged standing
  • Situational syncope: Associated with specific triggers (micturition, defecation, coughing, swallowing)
  • Carotid sinus syncope: In elderly, triggered by carotid sinus stimulation

2. Orthostatic Hypotension

  • Classic OH: Rapid BP drop on standing (SBP drop ≥20 mmHg or DBP drop ≥10 mmHg within 3 minutes)
  • Delayed OH: Progressive BP decline without initial recovery
  • Primary autonomic failure and secondary causes

3. Cardiac Syncope

  • Arrhythmia: Bradycardia (sinus node disease, AV block) or tachycardia (VT, SVT)
  • Structural: Acute MI, HCM, ARVC, pulmonary hypertension, aortic stenosis
  • Highest risk category; requires thorough cardiac investigation
Figure 3: Pathophysiological Classification of Syncope
Pathophysiological Basis of Syncope Classification
Syncope classified by underlying pathophysiological mechanism: reflex syncope, orthostatic hypotension, or cardiac syncope.

Initial Evaluation

The initial evaluation of syncope is the cornerstone of diagnosis, often identifying the underlying cause in 50% of patients. It consists of careful history and physical examination, including orthostatic vital signs measurement.

History Taking

  • Detailed account of prodromal symptoms (palpitations, dyspnea, chest pain, dizziness)
  • Circumstances and triggers of syncope (posture, emotion, exertion, pain)
  • Recovery characteristics (gradual vs. rapid, confusion, injury)
  • Eyewitness accounts of loss of consciousness and motor activity
  • Previous syncopal episodes and family history of SCD
  • Medications, substance use, comorbidities

Physical Examination

  • Baseline supine blood pressure and heart rate
  • Orthostatic vital signs: Measure after 3 minutes supine rest, then at 1 and 3 minutes of standing
  • Cardiovascular examination (murmurs, arrhythmias, signs of HCM)
  • Neurological examination (identify seizure activity, focal deficits)
  • Carotid sinus massage (CSM) in elderly with unexplained syncope (if no contraindications)
Figure 4: Initial Evaluation and Risk Stratification Flow Diagram
Flow Diagram for Initial Evaluation and Risk Stratification
Systematic approach to evaluating syncope patients through history, physical examination, and risk stratification.

Diagnosis of Syncope

A positive diagnosis of syncope type is made when the clinical features meet Class I criteria for one of the three main categories. This directed approach reduces unnecessary testing.

Risk Stratification

Risk stratification at initial evaluation and in the emergency department determines the intensity and setting of subsequent investigations. Patients are classified as high-risk or low-risk based on clinical features and initial test results.

High-Risk Features

  • Abnormal ECG (e.g., long QT, Brugada pattern, ARVC features, prior MI)
  • Syncope during exertion or in supine position
  • Palpitations preceding syncope
  • Family history of sudden cardiac death (SCD)
  • Age >60 years with comorbidities
  • Structural heart disease (HCM, LVEF <35%, aortic stenosis)
  • Persistent hypotension or bradycardia during syncope

Low-Risk Features

  • Clear prodrome (nausea, warmth, visual disturbance)
  • Syncope after sudden emotional stress or pain
  • Syncope during prolonged standing or crowded situations
  • Rapid recovery, orientation immediately after event
  • Normal ECG and cardiac examination
  • Age <60 with no heart disease
Figure 6: Emergency Department Risk Stratification
Emergency Department Risk Stratification Flow Chart
Decision pathway for identifying high-risk syncope patients requiring immediate intervention or admission.

Class I Low-risk patients should be discharged from ED (Class I). High-risk patients require observation unit or hospitalization (Class I). Risk stratification scores may be considered but do not replace clinical judgment (Class IIb).

Reflex (Vasovagal) Syncope

Reflex syncope is the most common syncope type, accounting for 50–80% of all syncope cases. It results from a sudden loss of vascular tone and/or heart rate due to a neurogenic mechanism, usually with a clear trigger.

Clinical Features

  • Prolonged prodrome with warning symptoms (nausea, warmth, dizziness, blurred vision)
  • Clear emotional, pain, or situational trigger
  • Gradual onset of loss of consciousness
  • Brief, usually generalized motor jerks (not true seizure)
  • Rapid recovery without confusion
  • Normal or low-normal baseline blood pressure

Treatment Strategies

Physical Counter-Pressure Manoeuvres (First-Line)

  • Leg crossing and abdominal tensioning: Most effective; can abort syncope in 50% of cases
  • Sitting or lying down immediately: Prevents loss of consciousness
  • Effective in 80% of patients with prodromal symptoms
  • Education and training essential for patient compliance

Pharmacological Options

  • Fludrocortisone (0.1 mg daily): Increases blood volume; for recurrent episodes
  • Midodrine (2.5–10 mg TID): Alpha-1 agonist; for patients who fail non-pharmacological measures
  • Atenolol (25–50 mg daily): Beta-blocker; controversial evidence, may consider in young patients

Pacing for Reflex Syncope

Cardiac pacing is reserved for recurrent, severely disabling reflex syncope resistant to conservative measures, particularly in elderly patients with a positive CSM response.

Indication Recommendation Class Evidence
Positive cardioinhibitory CSM with recurrent syncope Pacing may be considered for severely symptomatic, older patients IIb B
Reflex syncope with sinus bradycardia/arrest Pacing may be considered in selected, recurrent cases IIb C
Vasovagal syncope alone (without bradycardia) Pacing not recommended III B

Orthostatic Hypotension

Orthostatic hypotension (OH) is defined as a drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing, resulting in syncope or presyncope.

Classification

  • Classic OH: Immediate BP drop on standing (within 15 seconds)
  • Delayed OH: Progressive BP decline over 1–3 minutes
  • Primary autonomic failure: Parkinson disease, multiple system atrophy, pure autonomic failure
  • Secondary causes: Medications (diuretics, vasodilators), dehydration, bed rest, diabetes

Diagnostic Testing

  • Active standing test: Supine BP, then standing BP at 1 and 3 minutes (Class I)
  • Head-up tilt testing: May reproduce symptoms if diagnosis unclear
  • Autonomic function tests: Valsalva, deep breathing, 24-hour ambulatory BP monitoring for selected cases

Treatment

Non-Pharmacological (First-Line)

  • Increased fluid intake (2–3 liters daily)
  • Increased salt intake (6–10 grams daily, if tolerated)
  • Compression stockings or abdominal binders
  • Head-up bed tilt (30° angle) at night
  • Slow position changes; avoid prolonged standing
  • Physical counter-pressure manoeuvres

Pharmacological Options

  • Fludrocortisone (0.1–0.2 mg daily): Increases sodium retention and blood volume
  • Midodrine (2.5–10 mg TID): Alpha-1 agonist; most effective for symptomatic OH
  • Domperidone: May improve gastric emptying and BP (Class IIb)
  • Review and discontinue offending medications when possible

Class I Diagnosis of OH should be confirmed with standing BP measurement. Non-pharmacological measures are first-line; pharmacotherapy for symptomatic patients failing lifestyle modifications.

Cardiac Syncope

Cardiac syncope has the worst prognosis, with risk of sudden cardiac death up to 25% at 2 years. Immediate intensive evaluation and risk-stratifying diagnostic tests are essential.

Arrhythmia-Related Syncope

Bradycardia

  • Sinus node disease: Sinus arrest, severe bradycardia; especially in elderly
  • AV block: 2nd or 3rd degree, often paroxysmal
  • Bifascicular or bundle branch block: Risk of impending high-degree AV block

Tachycardia

  • Ventricular tachycardia (VT): Ischemic or non-ischemic substrate; high-risk
  • Long QT syndrome: Polymorphic VT (Torsades de Pointes)
  • Brugada syndrome: ECG pattern with fever or Na-channel blocker use
  • Catecholaminergic polymorphic VT (CPVT): Exercise-induced VT
  • SVT: Less likely to cause syncope, but possible with rapid rates

Structural Heart Disease

  • Acute MI: Mechanical complication or arrhythmia
  • Hypertrophic cardiomyopathy (HCM): Exertional syncope is high-risk marker
  • Arrhythmogenic right ventricular cardiomyopathy (ARVC): Task force criteria; consider ICD
  • Dilated cardiomyopathy (LVEF <35%): Consider ICD for primary prevention
  • Aortic stenosis: Exertional syncope; assess valve area
  • Pulmonary hypertension: Limited cardiac output during exertion

Pacing for Cardiac Bradycardia

Diagnosis Pacing Indication Class Evidence
Asymptomatic sinus bradycardia (<40 bpm) Not indicated III C
Sinus node disease with syncope Permanent pacing recommended I C
2nd degree AV block type II with syncope Permanent pacing recommended I C
3rd degree AV block Permanent pacing recommended I C
Bifascicular block with abnormal EPS Permanent pacing may be considered I C

Class I All patients with cardiac syncope require ECG. Abnormal ECG or high-risk features warrant admission, ECG monitoring, and intensive investigation. ICD therapy is indicated for EF <35% and secondary prevention in survivors of VT/VF.

Diagnostic Testing for Syncope

Diagnostic tests should be selected based on initial evaluation and risk stratification. Unnecessary testing is discouraged; targeted evaluation guided by clinical findings improves diagnostic yield and cost-effectiveness.

Electrocardiography

Class I 12-lead ECG is recommended for all syncope patients.

  • Red flag abnormalities: Long QT, short QT, Brugada pattern, ARVC features, prior MI, LVEF <35%
  • Bradycardia (<50 bpm), tachycardia (>100 bpm), bundle branch block
  • High-risk patterns warrant further investigation (imaging, monitoring, EPS)

Orthostatic Challenge

Class I Active standing test (supine to standing, measure BP at 1 and 3 minutes).

  • Low-cost, simple, diagnostic for classic orthostatic hypotension
  • Should be performed during initial evaluation in all patients

Carotid Sinus Massage (CSM)

Class I CSM recommended in older patients (age >60) with unexplained syncope.

  • Positive response: Syncope or presyncope with ≥3 second sinus pause or ≥50 mmHg SBP drop
  • Contraindications: Carotid bruits, history of stroke/TIA, recent MI, severe CAD
  • Can guide pacing decisions in cardioinhibitory response

Tilt-Table Testing

Class IIa Tilt testing may be useful for:

  • Reproducing syncope in equivocal cases to confirm reflex syncope diagnosis
  • Identifying vasovagal vs. cardioinhibitory response patterns
  • Educating patients about the benign nature of reflex syncope
Figure 7: Tilt Testing Positivity Rates by Clinical Condition
Rates of Tilt Testing Positivity in Different Clinical Conditions
Diagnostic utility of tilt-table testing across various clinical presentations and syncope types.

Cardiac Monitoring

Class I Continuous in-hospital ECG monitoring for high-risk patients.

  • Holter monitoring (24–48 hours): Low diagnostic yield; consider if symptoms occur regularly
  • External loop recorders: Event-triggered recording; useful for infrequent events
  • Implantable loop recorders (ILR): 3-year battery; for unexplained syncope with high-risk features
  • Remote telemetry: Increasing use for home monitoring; Class IIa

Echocardiography

Class I Echocardiography recommended if structural heart disease is suspected (cardiac examination findings, ECG abnormalities, dyspnea).

  • Assess LVEF, valvular disease, HCM, ARVC features
  • Stress echo for exercise-induced syncope (HCM, CPVT)

Electrophysiological Study (EPS)

Class I EPS recommended for:

  • Bifascicular bundle branch block with syncope (abnormal EPS predicts high-degree AV block)
  • Suspected sinus node disease (prolonged SNRT, abnormal SA conduction)
  • Suspected inducible VT (prior MI, reduced EF, family history)

Cardiac Monitoring & ILR Use

Prolonged electrocardiographic monitoring is indicated in high-risk patients with unexplained syncope to detect paroxysmal arrhythmias.

Monitoring Options

Modality Duration Indication Class
In-hospital monitoring 24–72 hours High-risk features, suspicion of arrhythmia I
Holter monitoring 24–48 hours Regular symptoms; low diagnostic yield IIb
External event recorder 1–4 weeks Infrequent syncope episodes IIa
External loop recorder 1–4 weeks Prospective monitoring; preferred over Holter IIa
Implantable loop recorder 3 years Unexplained syncope with high-risk features IIa

Implantable Loop Recorder (ILR) Criteria

Class IIa ILR may be considered in unexplained syncope with:

  • Frequent recurrences (>1 episode per month)
  • High-risk features (abnormal ECG, structural disease, age >60)
  • Severe consequences of syncope (injury, seizure-like activity)
  • Initial diagnostic workup unrevealing

Key Recommendations: Do's & Don'ts

Initial Evaluation (DO)

  • Perform careful history, eyewitness account, physical exam
  • Measure supine and standing BP (active standing test)
  • Obtain 12-lead ECG in all patients
  • Risk stratify immediately (high-risk vs. low-risk features)
  • Perform CSM in elderly patients (age >60) if indicated

Initial Evaluation (DON'T)

  • Do NOT order routine lab work, imaging, or CT without indication
  • Do NOT rely on EEG to diagnose syncope (high false-positive rate)
  • Do NOT admit all syncope patients; risk stratify
  • Do NOT order cardiac monitoring for all; use in high-risk only

Reflex Syncope (DO)

  • Educate patients about triggers and prodromal symptoms
  • Teach physical counter-pressure manoeuvres (leg crossing, abdominal tensioning)
  • Increase fluid and salt intake for recurrent episodes
  • Consider fludrocortisone or midodrine if conservative measures fail

Reflex Syncope (DON'T)

  • Do NOT use pacing routinely; reserve for recurrent, severe cases
  • Do NOT place without confirmation of vasovagal mechanism
  • Do NOT use beta-blockers as first-line (limited evidence)
  • Do NOT expect medications alone to prevent recurrence

Orthostatic Hypotension (DO)

  • Confirm diagnosis with standing BP measurement (Class I criteria)
  • Increase fluid intake to 2–3 liters daily
  • Add salt 6–10 grams daily if tolerated
  • Use compression stockings and head-up bed tilt
  • Start midodrine for symptomatic patients (most effective)

Orthostatic Hypotension (DON'T)

  • Do NOT diagnose from supine-sitting BP drop alone
  • Do NOT ignore medication-induced causes (diuretics, vasodilators)
  • Do NOT use fludrocortisone as monotherapy; combine with other measures
  • Do NOT start treatment without ruling out secondary causes

Cardiac Syncope (DO)

  • Admit high-risk patients to observation unit or hospital
  • Obtain ECG, echo, and cardiac monitoring immediately
  • Refer to cardiology/EP for suspected arrhythmia or structural disease
  • Consider ICD in appropriate candidates (EF <35%, SCD risk)

Cardiac Syncope (DON'T)

  • Do NOT delay workup for cardiac syncope
  • Do NOT dismiss exertional syncope as simple vasovagal
  • Do NOT use symptom-limited stress test alone; assess structural disease first
  • Do NOT ignore family history of SCD or syncope

Testing & Monitoring (DO)

  • Target diagnostic tests based on clinical presentation
  • Use tilt testing to confirm reflex syncope diagnosis
  • Consider ILR for unexplained high-risk syncope (recurrent, injuries)
  • Use Syncope Units for efficient, cost-effective risk stratification

Testing & Monitoring (DON'T)

  • Do NOT order routine Holter; low diagnostic yield
  • Do NOT use tilt testing for every syncope patient
  • Do NOT rely on scoring systems alone; use clinical judgment
  • Do NOT place ILR without adequate initial workup and high-risk features

Related Calculators

The following clinical tools complement syncope evaluation and risk assessment:

Corrected QT (QTc)

Calculate heart rate-corrected QT interval to identify prolongation risk

Brugada Risk Assessment

Assess risk in suspected Brugada syndrome and sudden cardiac death

HCM Risk Calculator

5-year sudden cardiac death risk in hypertrophic cardiomyopathy

SVT Differential Diagnosis

Differentiate SVT types from ECG features during arrhythmia

Pacemaker Dependency Assessment

Assess patient pacing dependence and device optimization

Disclaimer: This quick reference is intended as an educational tool for healthcare professionals. Always consult the full 2018 ESC Guidelines for Syncope and apply clinical judgment in individual patient care. Not all recommendations may apply to every patient.

Citation: Brignole M, Moya A, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. European Heart Journal. 2018;39(21):1883–1948. DOI: 10.1093/eurheartj/ehy037

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