What is the recommended workup and treatment for a patient presenting with syncope?

Syncope Workup and Management

The recommended workup for syncope should begin with initial evaluation consisting of detailed history, physical examination, orthostatic blood pressure measurements, and 12-lead ECG, followed by risk stratification to determine the need for further testing and hospital admission. 1, 2

Initial Evaluation

History and Physical Examination

• Key historical features to assess:
  • Circumstances surrounding the event (position, activity, triggers)
  • Presence of prodromal symptoms (nausea, diaphoresis, visual changes)
  • Duration of loss of consciousness
  • Post-event symptoms
  • Family history of sudden cardiac death
  • Medication review

Diagnostic Tests for All Patients

• 12-lead ECG (Class I recommendation) 2
• Orthostatic vital signs: Measure BP and heart rate after 5-10 minutes lying down, then at 1 and 3 minutes after standing 2
  • Diagnostic criteria for orthostatic hypotension: drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing

Risk Stratification

High-Risk Features (Requiring Hospital Admission)

• Age >60 years
• Abnormal cardiac examination
• Syncope during exertion
• Syncope without warning/prodrome
• Family history of sudden cardiac death
• Abnormal ECG findings:
  • Sinus bradycardia <40 beats/min
  • Sinoatrial blocks or sinus pauses >3 seconds
  • Mobitz II 2nd or 3rd degree AV block
  • Alternating bundle branch block
  • Rapid paroxysmal SVT or VT
  • Pacemaker malfunction 1

Low-Risk Features (Suitable for Outpatient Management)

• Age <45 years
• Normal ECG
• No known cardiac disease
• Presence of prodrome
• Situational triggers (e.g., pain, emotional stress)
• Postural change-related 2

Additional Testing Based on Initial Evaluation

For Suspected Cardiac Syncope

• Continuous ECG monitoring for hospitalized patients (Class I) 2
• Echocardiogram if structural heart disease suspected (Class IIa) 2
• Exercise stress testing if syncope occurs during exertion (Class IIa) 2
• Electrophysiological study for selected patients with suspected arrhythmic etiology (Class IIa) 2
• Implantable cardiac monitor for infrequent symptoms (>30 days between episodes) (Class IIa) 2

For Suspected Neurally-Mediated Syncope

• Tilt-table testing for suspected vasovagal syncope or delayed orthostatic hypotension (Class IIa) 2
• Carotid sinus massage in patients >40 years 1

Tests NOT Routinely Recommended

• MRI/CT of head (Class III: No Benefit)
• Carotid artery imaging (Class III: No Benefit)
• Routine EEG (Class III: No Benefit) 2
• Laboratory tests only if clinically indicated (e.g., hemoglobin if bleeding suspected) 3

Treatment Approach

Neurally-Mediated Syncope

• Patient education on:
  • Trigger avoidance
  • Physical counterpressure maneuvers (leg crossing with muscle tensing, squatting)
  • Increased salt and fluid intake
  • Avoiding sudden position changes 2

Orthostatic Hypotension

• Non-pharmacological interventions:
  • Increased fluid and salt intake
  • Physical counterpressure maneuvers
  • Compression garments
• Pharmacological options:
  • Midodrine (if no hypertension)
  • Fludrocortisone 2

Cardiac Syncope

• Treatment directed at underlying cardiac condition
• Consider cardiology referral for high-risk patients
• Potential interventions:
  • Antiarrhythmic medications
  • Pacemaker implantation
  • Implantable cardioverter-defibrillator (especially for patients with EF ≤25%) 4
  • Ablation procedures 5

Follow-up Considerations

Driving Restrictions

• 1-month restriction for syncope of undetermined etiology
• 3-month restriction for cardiac cause after treatment
• No restriction for reflex syncope with clear trigger if trigger can be avoided 2

Prognosis

• Cardiac syncope: Higher mortality (18-33% at 1 year)
• Non-cardiac causes: Lower mortality (3-4% at 1 year) 2
• Patients with coronary artery disease and reduced ejection fraction (≤25%) remain at risk for sudden death despite negative electrophysiologic studies 4

Important Caveats

• The diagnostic yield of the initial evaluation can be up to 50% of cases 5
• Patients with presyncope should undergo the same evaluation as those with syncope 5
• Bundle branch block on initial ECG predicts higher risk of bradycardia-related syncope 4
• Standardized evaluation approaches reduce hospital admissions and medical costs 5
• Even with a negative electrophysiologic study, patients with coronary artery disease and severely reduced EF may have up to 10% annual risk of sudden death 4