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Syncope
W. Kissinger
Tintinalli Sixth Edition
Chapter 52
Syncope
. . . . a sudden, transient loss of
consciousness associated with
inability to maintain postural tone.
Pathophysiology
Final Pathway
Lack of vital nutrient delivery to the
brainstem reticular activating system
loss of consciousness and postural tone
Pathophysiology
#1
Drop in cardiac output
Decrease in oxygen and substrate delivery to the
brain
#2
Vasospasm
Etiology
Cardiac dysrhythmia
Vasovagal reflex-mediated
Orthostatic hypotension
Normal Response
Physical or emotional stress
 increased sympathetic outflow
 increase in heart rate, blood
pressure, and cardiac output
Reflex-Mediated Syncope
Abnormal autonomic nervous system
reflex
Inappropriate withdraw of sympathetic tone and
replacement with increased vagal tone
Vagal hyperactivity
Reflex-Mediated Syncope
Vasovagal
Situational
Carotid sinus hypersensitivity
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
Orthostatic Syncope
Autonomic dysfunction
Primary disease process
Secondary to the following:
Peripheral neuropathy
Medications
Spinal cord injury
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.
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
Cardiac Syncope
Heart is unable to provide adequate
cardiac output to maintain cerebral
perfusion
Dysrhythmias
Associated with underlying structural disease
Structural cardiopulmonary lesions
25 y/o presents after a syncopal event
with the following EKG
25 y/o presents after a syncopal event
with the following EKG
Long QT syndrome
Normal interval is 0.42 seconds
Cardiac Syncope
If caused by a dysrhythmia:
Typically sudden (prodromal symptoms lasting
less than 3 seconds)
Subjectively lack warning
Underlying Cardiopulmonary Structural
Disease
Aortic Stenosis (listen for the murmur)
Chest pain, DOE, and syncope
Pulmonary Embolism
Hypertrophic cardiomyopathy
Medications
Β-blockers and calcium channel blockers
Blunted heart rate response after orthostatic
stress
Diuretics
Volume depletion and orthostatic hypotension
Antipsychotics
Proarrhythmic properties
Psychiatric Illness
Generalized anxiety disorder
Major depressive disorder
Typically young, repeated episodes, multiple
prodromal symptoms and a positive review of
symptoms
Neurovascular Syncope
Brainstem ischemia causing a decrease in
blood flow to the reticular activating
system
S/S of posterior circulation ischemia
Diplopia, vertigo, nausea
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
(right>left).
Diagnosis?
Subclavian Steal Syndrome
Abnormal narrowing of the subclavian
artery proximal to the origin of the
vertebral artery
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
Easy Task?!?!?!
Just rule-out the following:
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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
History
Patient and witnesses
Events
Duration/Symptoms
Past medical history
Medications
Family history
Physical Examination
Trauma without defensive injuries
Cardiovascular system
Murmur
Unequal blood pressures
Orthostasis
Neurologic system
Focal neurologic findings
Rectal Exam
History, Physical and EKG. . . .
EKG
Prior cardiopulmonary disease
Acute ischemia
Dysrhythmia
Heart block
Prolonged QT
Lab Testing
Dictated by H & P
CBC
Pregnancy test
Electrolytes
Disposition
Should they stay or should they go?
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
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
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
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: H&P, 12 lead, glucose,
hgb) followed one year
Four independent risk factors: >65 years, hx
cardiovascular dz, syncope w/o prodrome,
abnormal EKG
1 (0.8- 8.5%). . . . . . 4 (52.9%)
Academic Emergency Medicine Dec 2003
A Risk Score to Predict Arrhythmias in
Patients with Unexplained Syncope
<65 years, normal EKG, no Hx of CHF
0 (2%), 1 (17%), . . . . . . 3 (27%)
Questions
1. The most common cause of syncope is
A. Orthostatic hypotension
B. Vasovagal
C. Cardiac dysrhythmia
D. Situational
Questions
2. Classic symptoms of orthostatic
syncope include all of the following except
A. Blurred Vision
B. Dizziness
C. Vertigo
D. Tunnel Vision
Questions
3. The classic presentation of Syncope
from aortic stenosis include.
A. Chest Pain
B. Syncope
C. Dyspnea on exertion
D. Palpitations
Questions
4. Which on of the following criteria
according to Tintinalli define Orthostatic
Hypotension
A. Increase in HR > 20 BPM
B. Decrease in Systolic BP of 10mmHg
C. Decrease in Systolic BP of 20mmHg
E. A and C
F. A and B
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
Answers
1. B
2. C
3. D
4. C
5. T
6. F
7. T