Syncope

Background

• 3 Questions

1. Is this true syncope or something else (eg, stroke, seizure, head injury)?
2. If this is true syncope, is there a clear life-threatening cause?
3. If this is true syncope and the cause is not clear, is the pt at high risk?

• Etiology is divided into 3 major categories
• Clinical features in each category suggesting diagnosis of syncope:

1. Cardiovascular-mediated syncope
   1. Usually occurs without warning
   2. H/o structural heart disease
   3. Family Hx of sudden cardiac death
   4. Syncope during exertion
   5. Palpitations associated with syncope
   6. Abnormal ECG
2. Neurally mediated syncope
   1. Trigger event (fear/pain, prolonged standing, warm environment)
   2. Prodrome of nausea, vomiting, tunnel vision, lightheadedness, diaphoresis, warmth
   3. Associated with head movement or pressure on neck
3. Orthostatic hypotension-mediated syncope
   1. After standing up
   2. Change in medications

Risk Factors for Serious Cause

1. Exertion preceding the event
2. History of cardiac disease in the patient
3. Family history of sudden death, deafness, or cardiac disease
4. Recurrent episodes
5. Recumbent episode
6. Prolonged loss of consciousness
7. Associated chest pain or palpitations
8. Use of medications that can alter cardiac conduction

San Francisco Syncope Rule

• 1.4% of patients who are rule-negative will have a 7-day serious outcome
• 10% of patients meeting the below criteria will have a 7-day serious outcome

Criteria (CHESS Pneumonic)

• CHF History
• Hct < 30%
• ECG Abnormality
• SOB history
• SBP < 90mmHg at triage

DDX

• Cardiovascular-mediated syncope:
  • Dysrhythmias:
    • WPW (pre-excitation)
    • Long QT syndrome
    • Brugada syndrome
    • 2nd/3rd degree AV block
    • Afib/aflutter
    • Vtach/torsades
    • Sick sinus syndrome
  • Cardiovascular disease:
    • Valvular disease (AS, MS, tricuspid stenosis)
    • Aortic dissection
    • Myocardial infarction
    • CHF
    • PE
    • Pericardial tamponade
    • Myxoma
    • Pulmonary HTN
• Neurally mediated syncope:
  • Vasovagal:
    • Fear, pain, emotion, valsalva, breath-holding spell
  • Situational (associated with):
    • Coughing, micturition, defecation, vomiting
    • Carotid sinus stimulation
• Orthostatic hypotension-mediated syncope:
  • Volume depletion:
    • Dehydration (vomiting, diarrhea)
    • Hemorrhage
    • Sepsis
  • Autonomic dysreflexia
  • Autonomic failure due to meds
• Other serious causes:
  • SAH
  • TIA
  • Subclavian steal

Physical Exam

• Evaluate volume status
• Evaluate for head and neck trauma (related to fall from syncopal event)
• Focus cardiac exam on detecting murmurs (AS, MR, tricuspid stenosis)
• Evaluate for signs of heart failure
• Palpate abdomen for pulsating mass (AAA)
• Rectal exam to eval for GI bleeding
• Thorough neurologic exam
• Examine for possible sources of infection

Work-Up

• Overall yield of testing is low
• Cardiovascular findings and evidence of bleeding strongest predictors of adverse outcomes after syncope

1. ECG
   1. Normal ECG has high NPV
   2. Perform on every pt, unless trigger clearly identified (i.e. following blood draw) and no risk factors
   3. R/o: Ischemia, heart block, WPW, long QT, Brugada
   4. ECG findings associated with adverse cardiac outcome in 30 days:
      1. LBBB, 2nd degree Mobitz II, 3rd degree AV block, RBBB w/LAFP or LPFB
2. Urine pregnancy

• Consider based on history/symptoms:

1. CXR
   1. Obtain if symptomatic (i.e. r/o dissection)
2. Hemoglobin
3. Chemistry
4. Orthostatics (symptomatic)
5. Troponin
   1. Not recommended to r/o AMI in patients with isolated syncope
   2. Elevated troponin predicts adverse cardiac outcome in syncope
   3. May be useful for risk stratification
6. Guaiac

Treat

1. Treat cause
   1. See also Hypotension

Disposition

1. Admit
   1. Abnormal ECG
   2. CHF
   3. Suspicion of structural heart disease
      1. Ischemic, dysrhythmic, obstructive, valvular
   4. HCT <30
   5. Shortness of Breath
   6. Hypotension (SBP <90)
   7. Family history of sudden cardiac death
   8. Advanced age
   9. Evidence of hemorrhage (occult blood)
2. Discharge
   1. None of the above findings (esp if age <45)
   2. Consider referral for holter or til-table test

Source

• Tintinalli
• UpToDate
• ACEP Clinical Policy 2007
• The NNT (http://thennt.com/risk/syncope-in-the-emergency-department)