What is the workup for a near syncope episode?

Workup for a Near Syncope Episode

The initial evaluation of a patient with near syncope should include a detailed history focusing on circumstances before the event, physical examination with orthostatic blood pressure measurements, and a 12-lead electrocardiogram (ECG). 1

Initial Assessment Components

• Obtain detailed information about circumstances before the attack, including position, activity, predisposing factors, and precipitating events 1, 2
• Document symptoms at onset, including presence of prodrome, palpitations before syncope, and recovery phase symptoms 1
• Perform a complete cardiovascular examination with attention to heart rate, rhythm, murmurs, gallops, or rubs that may indicate structural heart disease 1, 2
• Measure orthostatic blood pressure in lying, sitting, and standing positions 1, 2
• Obtain a 12-lead ECG to identify potential cardiac causes 1, 2

Risk Stratification

• High-risk features suggesting cardiac causes:

  • Older age (>60 years), male sex, known heart disease 1
  • Brief or absent prodrome, syncope during exertion or in supine position 1
  • Low number of episodes (1-2), abnormal cardiac examination 1
  • Family history of inheritable conditions or premature sudden cardiac death 1
  • Abnormal ECG findings (e.g., bifascicular block, conduction abnormalities) 1, 2

• Low-risk features suggesting non-cardiac causes:

  • Younger age, no known cardiac disease 1
  • Syncope only when standing, positional change triggers 1
  • Prodromal symptoms, specific situational triggers 1

Targeted Diagnostic Testing

• Cardiovascular Testing:

  • Echocardiography when structural heart disease is suspected 1, 2
  • Exercise stress testing for syncope during or after exertion 1, 2
  • Cardiac monitoring based on frequency of symptoms:
    • Holter monitor for episodes occurring at least daily 2
    • Event recorder for episodes occurring at least monthly 2
    • Implantable loop recorder for infrequent episodes 2

• Laboratory Testing:

  • Targeted blood tests based on clinical assessment rather than routine comprehensive testing 1, 2
  • Consider CBC/hematocrit when volume depletion is suspected 1
  • Consider electrolytes and glucose when metabolic disorders are suspected 1
  • Consider cardiac biomarkers (BNP, troponin) only when cardiac cause is suspected 1

• Neurological Testing:

  • Brain imaging (CT/MRI) is not recommended routinely, with diagnostic yield of only 0.24-1% 1
  • EEG is not recommended routinely, with diagnostic yield of only 0.7% 1
  • Carotid artery imaging is not recommended routinely, with diagnostic yield of only 0.5% 1

• Specialized Testing:

  • Tilt-table testing for young patients with recurrent unexplained syncope without suspicion of heart disease 1, 2
  • Carotid sinus massage in patients over 40 years 1, 2
  • Electrophysiological studies in selected cases with suspected arrhythmic syncope 1

Management of Unexplained Near Syncope

• Reappraise the entire workup for subtle findings or new information 1, 2
• Consider specialty consultation if unexplored clues to cardiac or neurological disease are present 1, 2
• Consider implantable loop recorder for recurrent unexplained episodes 1, 2

Common Pitfalls to Avoid

• Failing to distinguish near syncope from non-syncopal causes of transient symptoms 1
• Ordering comprehensive laboratory testing without clinical indication 1, 2
• Ordering brain imaging studies (CT/MRI) without specific neurological indications 1
• Overlooking medication effects as potential contributors to near syncope 1
• Overlooking orthostatic hypotension as a potential cause 1

Disposition Decision

• Consider hospital admission for:

  • Serious medical conditions identified during initial evaluation 1
  • Suspected cardiac syncope with abnormal ECG or structural heart disease 1
  • High-risk features suggesting increased morbidity and mortality 1

• Consider outpatient management for:

  • Presumptive reflex-mediated (neurally mediated) near syncope without serious medical conditions 1
  • Low-risk features (younger age, no known cardiac disease, normal ECG) 1