What is the appropriate workup for a patient presenting with syncope?

Syncope Evaluation and Management

The appropriate workup for syncope should include a detailed history, physical examination with orthostatic blood pressure measurements, and a 12-lead ECG as the initial evaluation, which can establish the diagnosis in 23-50% of cases. 1

Initial Evaluation

History

• Position when syncope occurred (supine, sitting, standing)
• Activity at time of event (rest, exercise, after exertion, during urination/defecation)
• Predisposing factors (crowded/warm places, prolonged standing, post-prandial)
• Prodromal symptoms (nausea, sweating, blurred vision, feeling cold)
• Eyewitness account (manner of falling, skin color, duration of unconsciousness, breathing pattern, movements)
• Post-event symptoms (confusion, muscle aches, injury) 2, 1

Physical Examination

• Complete cardiovascular examination
• Orthostatic blood pressure measurements (mandatory)
• Neurological examination if non-syncopal loss of consciousness is suspected 1

Initial Testing

• 12-lead ECG (Class I recommendation) 1
• Carotid sinus massage in patients >40 years, especially if syncope occurs during neck turning 2

Risk Stratification

High-Risk Features (requiring hospitalization)

• Age >60 years
• Known ischemic or structural heart disease
• Abnormal ECG
• Syncope during exertion or in supine position
• Absence of prodrome
• Family history of sudden cardiac death 1

Low-Risk Features (can be managed outpatient)

• Younger age
• No known cardiac disease
• Normal ECG
• Typical prodrome
• Positional trigger
• Frequent recurrence with similar characteristics 1

Directed Testing Based on Initial Evaluation

For Suspected Cardiac Syncope

1. Echocardiography if structural heart disease is suspected
2. Prolonged ECG monitoring based on frequency of events:
   • Holter monitor (24-48 hours) for frequent episodes
   • External loop recorder (up to 30 days) for less frequent episodes
   • Implantable cardiac monitor for rare episodes
3. Exercise stress testing if syncope occurs during exertion
4. Electrophysiological studies if arrhythmia is suspected and non-invasive tests are non-diagnostic 2, 1

For Suspected Reflex (Neurally-Mediated) Syncope

1. Tilt table testing, especially in younger patients with recurrent syncope
2. Carotid sinus massage in older patients 2, 1

For Suspected Orthostatic Hypotension

1. Lying-to-standing orthostatic test
2. Head-up tilt testing 2, 1

Important Caveats

• Basic laboratory tests should only be performed if volume depletion or metabolic disorder is suspected, not routinely 2, 1
• Neuroimaging is not recommended routinely and should be performed only when neurological causes are suspected 1
• Reappraisal of the diagnostic workup is necessary if initial evaluation is non-diagnostic 2
• Avoid common pitfalls:
  • Overuse of neuroimaging
  • Routine comprehensive laboratory testing
  • Missing orthostatic hypotension
  • Overlooking medication-related causes 1
  • Failure to distinguish between different types of dizziness 1

Specialized Testing for Unexplained Syncope

• Implantable loop recorder for prolonged monitoring in recurrent unexplained syncope 2, 1
• ATP testing may be indicated at the end of the diagnostic workup 2
• Psychiatric assessment for patients with frequent episodes and multiple somatic complaints 2, 1

The European Society of Cardiology guidelines emphasize that a structured approach to syncope evaluation can reduce unnecessary testing, decrease hospital stays by 29%, and lower the cost per diagnosis by 29% 2.