What is the approach to evaluating syncope in the emergency setting?

Approach to Evaluating Syncope in the Emergency Setting

The evaluation of syncope in the emergency department should focus on risk stratification to identify patients with life-threatening conditions requiring hospital admission while avoiding unnecessary testing and admissions for low-risk patients. 1

Initial Assessment

• A resting 12-lead ECG is essential in the initial evaluation of all patients with syncope 1
• Detailed history focusing on:
  • Circumstances surrounding the event (exertional, supine position, prodromal symptoms) 1
  • Alarming symptoms: syncope during exertion, syncope in lying position, absence of external factors, family history of sudden cardiac death, slow recovery 1
  • Features suggesting cardiac causes: older age (>60 years), male sex, known heart disease, brief/absent prodrome, low number of episodes 1
  • Features suggesting non-cardiac causes: younger age, standing position, clear triggers, prodromal nausea/warmth 1
• Physical examination with orthostatic blood pressure measurements 1

Risk Stratification

• High-risk features requiring admission:

  • Serious medical conditions identified during initial evaluation 1
  • Abnormal ECG findings suggesting arrhythmia 1
  • History of heart failure or structural heart disease 1
  • Syncope during exertion or while supine 1
  • Family history of sudden cardiac death 1
  • Absence of prodrome 1

• Intermediate-risk features:

  • Recurrent episodes without clear diagnosis 1
  • Age >60 years without clear vasovagal features 1
  • Structured emergency department observation protocols can effectively reduce hospital admission rates in these patients 1

• Low-risk features (suitable for outpatient management):

  • Presumptive reflex-mediated (vasovagal) syncope 1
  • Clear situational triggers 1
  • Young age without cardiac disease 1
  • Normal ECG and cardiac examination 1

Diagnostic Testing

• Targeted testing is recommended over routine comprehensive testing 1
• Targeted blood tests are reasonable based on clinical assessment from history, physical examination, and ECG 1
• Brain natriuretic peptide and high-sensitivity troponin measurement have uncertain utility even when cardiac cause is suspected 1
• Routine comprehensive laboratory testing is not useful 1
• Cardiac imaging (echocardiography) is useful only when structural heart disease is suspected 1
• Routine cardiac imaging is not useful unless cardiac etiology is suspected based on initial evaluation 1
• Exercise stress testing can be useful for patients with exertional syncope 1

Cardiac Monitoring

• The choice of cardiac monitor should be determined by the frequency and nature of syncope events 1
• For hospitalized patients with suspected cardiac etiology, continuous ECG monitoring is useful 1
• For selected ambulatory patients with suspected arrhythmic syncope, external monitoring options include:
  • Holter monitor (for symptoms likely to recur within 24-72 hours) 1
  • External loop recorder 1
  • Patch recorder 1
  • Mobile cardiac outpatient telemetry 1
• Implantable cardiac monitors can be useful for selected patients with suspected arrhythmic syncope 1

Disposition Decisions

• Hospital admission is recommended for patients with:

  • Identified serious medical conditions 1
  • High-risk features as outlined above 1
  • Suspected cardiac syncope with concerning features 1

• Outpatient management is appropriate for:

  • Presumptive reflex-mediated syncope without serious medical conditions 1
  • Low-risk patients with clear vasovagal features 1
  • Selected patients with suspected cardiac syncope without serious medical conditions 1

• Structured emergency department observation protocols (6-hour observation with telemetry, hourly vital signs, orthostatic blood pressure checks, and targeted testing) can reduce hospital admissions for intermediate-risk patients 1

Common Pitfalls to Avoid

• Ordering unnecessary neuroimaging without specific neurological indications (low yield of 0.24-1%) 2
• Relying on short-term ambulatory ECG monitoring (Holter) when symptoms are infrequent 3
• Failing to distinguish true syncope from seizures, pseudosyncope, or other causes of altered consciousness 3
• Overlooking medication effects as potential contributors to syncope 2
• Using broad-based testing rather than targeted evaluation based on initial assessment 4