Syncope

1
Syncope

• W. Kissinger
• Tintinalli Sixth Edition
• Chapter 52

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Syncope

• . . . . a sudden, transient loss of consciousness
  associated with inability to maintain postural
  tone.

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Pathophysiology

• ?Final Pathway?
• Lack of vital nutrient delivery to the brainstem
  reticular activating system
• ?loss of consciousness and postural tone

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Pathophysiology

• 1
• Drop in cardiac output
• Decrease in oxygen and substrate delivery to the
  brain
• 2
• Vasospasm

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Etiology

• Cardiac dysrhythmia
• Vasovagal reflex-mediated
• Orthostatic hypotension

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Normal Response

• Physical or emotional stress
• ? increased sympathetic outflow
• ?? increase in heart rate, blood pressure, and
  cardiac output

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Reflex-Mediated Syncope

• Abnormal autonomic nervous system reflex
• Inappropriate withdraw of sympathetic tone and
  replacement with increased vagal tone
• Vagal hyperactivity

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Reflex-Mediated Syncope

• Vasovagal
• Situational
• Carotid sinus hypersensitivity

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Orthostatic Syncope

• Insufficient autonomic response
• Normally
• Upright posture? blood shifted to lower extremity
  ?cardiac output drops? increase in sympathetic
  output and decrease in parasympathetic output? ?
  HR and PVR? ? CO and BP

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Orthostatic Syncope

• Autonomic dysfunction
• Primary disease process
• Secondary to the following
• Peripheral neuropathy
• Medications
• Spinal cord injury

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Orthostatic Hypotension

• Defined by the consensus group of the American
  Autonomic Society as a sustained decrease in
  blood pressure exceeding 20 mmHg systolic or 10
  mmHg diastolic occurring within 3 minutes of
  upright tilt.

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Orthostatic Syncope

• Should have recurrence of syncopal symptoms on
  orthostatic testing
• Warning 5-55 of patients with other causes of
  syncope have orthostatic hypotension on exam

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Cardiac Syncope

• Heart is unable to provide adequate cardiac
  output to maintain cerebral perfusion
• Dysrhythmias
• Associated with underlying structural disease
• Structural cardiopulmonary lesions

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25 y/o presents after a syncopal event with the
following EKG
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25 y/o presents after a syncopal event with the
following EKG
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Long QT syndrome

• Normal interval is 0.42 seconds

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Cardiac Syncope

• If caused by a dysrhythmia
• Typically sudden (prodromal symptoms lasting less
  than 3 seconds)
• Subjectively lack warning

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Underlying Cardiopulmonary Structural Disease

• Aortic Stenosis (listen for the murmur)
• Chest pain, DOE, and syncope
• Pulmonary Embolism
• Hypertrophic cardiomyopathy

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Medications

• ?-blockers and calcium channel blockers
• Blunted heart rate response after orthostatic
  stress
• Diuretics
• Volume depletion and orthostatic hypotension
• Antipsychotics
• Proarrhythmic properties

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Psychiatric Illness

• Generalized anxiety disorder
• Major depressive disorder
• Typically? young, repeated episodes, multiple
  prodromal symptoms and a positive review of
  symptoms

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Neurovascular Syncope

• Brainstem ischemia causing a decrease in blood
  flow to the reticular activating system
• S/S of posterior circulation ischemia
• Diplopia, vertigo, nausea

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Question???

• 25 year old left-handed male presents to the ED
  after a syncopal event while painting a fence.
  You note he has unequal blood pressures in his
  upper extremities (rightgtleft).
• Diagnosis?

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Subclavian Steal Syndrome

• Abnormal narrowing of the subclavian artery
  proximal to the origin of the vertebral artery

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Emergency Department Evaluation

• Goal Identify those at risk for immediate
  decompensation and those at future risk of
  serious morbidity or sudden death.
• ?History
• ?Physical Exam
• ?EKG

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Easy Task?!?!?!Just rule-out the following

• AMI
• PE
• aortic dissection
• cardiac tamponade
• tension pneumothorax
• leaking AAA
• active internal bleeding
• malignant cardiac arrhythmias
• ectopic pregnancy
• SAH
• carotid artery/vertebral artery dissection
• air embolism

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History

• Patient and witnesses
• Events
• Duration/Symptoms
• Past medical history
• Medications
• Family history

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Physical Examination

• Trauma without defensive injuries
• Cardiovascular system
• Murmur
• Unequal blood pressures
• Orthostasis
• Neurologic system
• Focal neurologic findings
• Rectal Exam

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History, Physical and EKG. . . .
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EKG

• Prior cardiopulmonary disease
• Acute ischemia
• Dysrhythmia
• Heart block
• Prolonged QT

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Lab Testing

• Dictated by H P
• CBC
• Pregnancy test
• Electrolytes

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Disposition

• Should they stay or should they go?

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ACEP Task Force Recommendations

• Admit patients with syncope and any of the
  following
• 1. A history of congestive heart failure or
  ventricular arrhythmias 2. Associated chest pain
  or other symptoms compatible with acute coronary
  syndrome 3. Evidence of significant congestive
  heart failure or valvular heart disease on
  physical     examination 4. ECG findings of
  ischemia, arrhythmia, prolonged QT interval, or
  bundle branch block

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ACEP Recommendations

• Consider admission for patients with syncope and
  any of the following
• 1. Age older than 60 years 2. History of
  coronary artery disease or congenital heart
  disease 3. Family history of unexpected sudden
  death 4. Exertional syncope in younger patients
  without an obvious benign etiology for the    
  syncope

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Predictors of Sudden Cardiac Death or Significant
Dysrhythmia

• 1. Abnormal EKG
• 2. Age older than 45 years
• 3. History of ventricular dysrhythmia
• 4. History of congestive heart failure

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European Heart Journal, May 2003

• Development and Prospective Validation of a Risk
  Stratification System for Patients With Syncope
  in the ED The Oesil Risk Score
• 270 pts (syncope w/u HP, 12 lead, glucose,
  hgb)? followed one year
• Four independent risk factors gt65 years, hx
  cardiovascular dz, syncope w/o prodrome, abnormal
  EKG
• 1 (0.8- 8.5). . . . . . 4 (52.9)

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Academic Emergency Medicine Dec 2003

• A Risk Score to Predict Arrhythmias in Patients
  with Unexplained Syncope
• lt65 years, normal EKG, no Hx of CHF
• 0 (2), 1 (17), . . . . . . 3 (27)

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Questions

• 1. The most common cause of syncope is
• A. Orthostatic hypotension
• B. Vasovagal
• C. Cardiac dysrhythmia
• D. Situational

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Questions

• 2. Classic symptoms of orthostatic syncope
  include all of the following except
• A. Blurred Vision
• B. Dizziness
• C. Vertigo
• D. Tunnel Vision

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Questions

• 3. The classic presentation of Syncope from
  aortic stenosis include.
• A. Chest Pain
• B. Syncope
• C. Dyspnea on exertion
• D. Palpitations

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Questions

• 4. Which on of the following criteria according
  to Tintinalli define Orthostatic Hypotension
• A. Increase in HR gt 20 BPM
• B. Decrease in Systolic BP of 10mmHg
• C. Decrease in Systolic BP of 20mmHg
• E. A and C
• F. A and B

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Questions

• 5. T or F Bradycardia is most likely to be a
  incidental finding in syncope
• 6. T or F In cardiac syncope the typical prodrome
  last no more than 3 minutes
• 7. T or F Subclavian Steal syndrome is more
  common on the Left

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Answers

• 1. B
• 2. C
• 3. D
• 4. C
• 5. T
• 6. F
• 7. T