This document provides guidelines for evaluating and managing patients presenting with syncope. It defines syncope and distinguishes it from other causes of transient loss of consciousness. It covers the etiologies of syncope including neurocardiogenic, cardiovascular, and orthostatic causes. The guidelines recommend an initial evaluation including history, physical exam, ECG and risk stratification to determine if the patient is high or low risk. They provide guidance on cardiac and neurological testing, imaging, and monitoring based on the risk level. The guidelines also cover management strategies for specific causes of syncope.

1. Syncope
The current guideline- 2017
S M Ziaul Haque,
Department of Cardiology, SQH

2. What is Syncope?
• Syncope is the abrupt and transient loss
of consciousness associated with
absence of postural tone, followed by
complete and usually rapid spontaneous
recovery.
• The underlying mechanism is global
hypoperfusion of both the cerebral
cortices or focal hypoperfusion of the
reticular activating system (RAS).

3. What is Syncope?
• It is important to distinguish Syncope from other
causes of T-LOC (Transient Loss of Consciousness)
• Pre-Syncope: lightheadedness without LOC
• Drop Attack: loss of posture without LOC
• Coma: LOC without spontaneous recovery
• Seizure: Tonic-Clonic Movements that start WITH LOC (vs
hypoxic myoclonus which can occur with syncope), post-
ictal recovery period
• Hypoglycemia
• Hypoxia
• TIA
• Cardiac Arrest

4. Etiologies of Syncope
Neurocardiogenic / Vasovagal
Most Common
• Pain/Noxious Stimuli
• Situational (micturation, cough,
defecation)
• Carotid Sinus Hypersensitivity (CSH)
• Fear
• Prolonged standing / heat exposure
Cardiovascular
Most Dangerous
• Arrhythmia – Tachy or Brady
• Valve Stenosis (outflow obstruction)
• HOCM (outflow obstruction)
Orthostatic Hypotension
“ D A A D “
• Drugs: BP meds, Diuretics, TCAs
• Autonomic Insufficiency (Parkinsons,
Shy-Dragger, DM, Adrenal
Insufficiency)
• Alcohol
• Dehydration
Neuro / Functional / Psychiatric - <5%
• Psuedosyncope
• TIA or Vertibro-basilar Insufficiency

5. ACC/AHA Guideline 2017
Syncope Initial Evaluation

6. Risk Assessment
COR LOE Recommendations
I B-NR
Evaluation of the cause and assessment for the short-
and long-term morbidity and mortality risk of syncope are
recommended.
IIb B-NR
Use of risk stratification scores may be reasonable in the
management of patients with syncope.

9. Work-up and Risk Stratification
• The syncope work-up should determine who is at HIGH
RISK for a dangerous short-term cardiac event.
• All patient should get basic Work-up Including
• History/Physical including Orthostatics
• Medication Review
• ECG.
• If age >40, consider Carotid Sinus Massage to assess for Carotid Sinus
Hypersensitivity
• CONTRAINDICATED if carotid bruit present or recent TIA/Stroke
• + Test = bradycardia, hypotension, transient pause/asystole, or prodrome
symptoms
• All patients should then be Risk Stratified

10. Work-up and Risk Stratification
• Risk Stratification
• High Risk: These patients are at high risk for short term cardiac
mortality and need appropriate cardiac work-up as an INPATIENT
• Evidence of significant heart disease (such as heart failure, low left
ventricular ejection fraction, structural abnormality, or previous
myocardial infarction).
• Clinical (eg palpitations) or ECG features suggesting arrhythmia
• Comorbidities such as severe anemia or electrolyte disturbance.
• High Risk Work-Up
• Echo, Stress test, and/or Ischemic Evaluation
• Check for recent Echo and/or TMST before ordering a new one!
• Consider Posterior Circulation imaging of the brain if suspect
Neurological “syncope”
• Carotid Ultrasound has POOR utility in the workup of Syncope and
should not be ordered routinely.

11. Work-up and Risk Stratification
•Low Risk: Patient’s with no High risk characteristics
and/or with highly suspected Vasovagal or
Neurocardiogenic Etiology
• Single Episode: No further workup indicated
• Multiple Episodes: Can workup as outpatient
• Patient having FREQUENT Episodes: Holter Monitor or Event
Monitor
• Patient having INFREQUENT Episodes: Implantable Loop Recorder
• These patients DO NOT need “ACS Rule Out” or Imaging (including
Head CT or Carotid Ultrasound)

12. Imaging in the Workup of Syncope
• So When do I get Brain Imaging?
• Neurological Causes of true Syncope are RARE
• Bilateral Carotid or Basilar Artery Disease
• Non-convulsive Seizure
• Head CT is indicated ONLY if the patient has or experienced focal
neurological deficits or they experienced head trauma from the event.
• Carotid Ultrasound has LOW utility and should NOT be ordered
routinely.
• Posterior Circulation evaluation with CTA/MRA or Ultrasound is
useful only if Vertibro-basilar insufficiency is suspected
• Typically present with Dizziness, gait instability, blurry vision,
nystagmus, or frank Coma.

13. Neurological and Imaging Diagnostics- 2017
COR LOE Recommendations
IIa C-LD
Simultaneous monitoring of an EEG and hemodynamic
parameters during tilt-table testing can be useful to
distinguish among syncope, pseudosyncope, and
epilepsy.
III: No
Benefit
B-NR
MRI and CT of the head are not recommended in the
routine evaluation of patients with syncope in the absence
of focal neurological findings or head injury that support
further evaluation.
III: No
Benefit
B-NR
Carotid artery imaging is not recommended in the routine
evaluation of patients with syncope in the absence of focal
neurological findings that support further evaluation.
III: No
Benefit
B-NR
Routine recording of an EEG is not recommended in the
evaluation of patients with syncope in the absence of
specific neurological features suggestive of a seizure.

14. Cardiac Imaging
COR LOE Recommendations
IIa B-NR
Transthoracic echocardiography can be useful in selected
patients presenting with syncope if structural heart
disease is suspected.
IIb B-NR
CT or MRI may be useful in selected patients presenting
with syncope of suspected cardiac etiology.
III: No
Benefit
B-R
Routine cardiac imaging is not useful in the evaluation of
patients with syncope unless cardiac etiology is suspected
on the basis of an initial evaluation, including history,
physical examination, or ECG.
Cardiovascular Testing

15. Stress Testing
COR LOE Recommendation
IIa C-LD
Exercise stress testing can be useful to establish the
cause of syncope in selected patients who experience
syncope or presyncope during exertion.

16. Cardiac Monitoring
COR LOE Recommendations
I C-EO
The choice of a specific cardiac monitor should be
determined on the basis of the frequency and nature of
syncope events.
IIa B-NR
To evaluate selected ambulatory patients with syncope of
suspected arrhythmic etiology, the following external
cardiac monitoring approaches can be useful:
1. Holter monitor
2. Transtelephonic monitor
3. External loop recorder
4. Patch recorder
5. Mobile cardiac outpatient telemetry.
IIa B-R
To evaluate selected ambulatory patients with syncope of
suspected arrhythmic etiology, an ICM can be useful.

17. In-Hospital Telemetry
COR LOE Recommendation
I B-NR
Continuous ECG monitoring is useful for hospitalized
patients admitted for syncope evaluation with
suspected cardiac etiology.

18. Electrophysiological Study
COR LOE Recommendations
IIa B-NR
EPS can be useful for evaluation of selected patients
with syncope of suspected arrhythmic etiology.
III: No
Benefit
B-NR
EPS is not recommended for syncope evaluation in
patients with a normal ECG and normal cardiac
structure and function, unless an arrhythmic etiology is
suspected.

19. Tilt-Table Testing
COR LOE Recommendations
IIa B-R
If the diagnosis is unclear after initial evaluation, tilt-table
testing can be useful for patients with suspected VVS.
IIa B-NR
Tilt-table testing can be useful for patients with syncope
and suspected delayed OH when initial evaluation is not
diagnostic.
IIa B-NR
Tilt-table testing is reasonable to distinguish convulsive
syncope from epilepsy in selected patients.
IIa B-NR
Tilt-table testing is reasonable to establish a diagnosis of
pseudosyncope.
III: No
Benefit
B-R
Tilt-table testing is not recommended to predict a
response to medical treatments for VVS.

20. “Hey its Triage, have this syncope
admit”
• 71y/o M presents after he passed out while walking up the
stairs. He felt slightly lightheaded just prior to the event.
Wife saw him fall but was able to quickly arouse him. He had
no incontinence or tongue biting. Similar event occurred 2
weeks prior while he was doing yard-work for which he did
not seek medical care. He has a long history of DM, and
hypertension for which he takes Glipizide, Amlodipine,
Lisinopril, and HCTZ. He does not drink. Vitals, orthostatics,
and blood sugar are unremarkable. ECG shows left axis
deviation and LVH. Exam shows 1+ bilateral edema and 4/6
ejection murmur radiating to the carotids.
• What risk category is this patient and how would you
proceed with workup?

21. “Hey its Triage, have this syncope admit”
• H/P, Orthostatics, ECG, Meds
• ECG shows evidence of structural heart disease and exam
shows murmur. No orthostasis or suspicious history of
vasovagal syncope. Patient has had multiple episodes.
• Based on initial workup, patient is High Risk
o Needs Admission and Cardiac Work-up including
Echocardiogram and Stress Test
 Dx: Aortic Stenosis

22. “Last admit of the day!”
35y/o healthy M presents with an episode of syncope
while standing. He did not experience any prodrome
symptoms. This has never happened before. He has no
medical history and uses no medications, drugs, or EtoH.
Physical exam and ECG are normal. No orthostasis.
Carotid massage is negative. Routine labs are
unremarkable.
• What risk category is this patient and how would you
proceed with workup?

23. Last admit of the day!
• H/P, Orthostatics, ECG, Meds - normal with no obvious cause of syncope
• Patient is Low Risk and has had only a Single Episode of syncope
 No Further Work-up Indicated
• What if the same patient presented with syncope while working
out at the gym and physical exam showed a grade III systolic
murmur that increased with Valsalva?
o Patient is now High Risk given possible structural heart disease and
exertional syncope
 Admit to telemetry for cardiac work-up including
Echocardiogram to evaluate for Hypertrophic
Cardiomyopathy.

24. Patient Disposition After Initial Evaluation for Syncope

25. Additional Evaluation and Diagnosis

26. Key Points
• Key Differential Dx
o
Vasovagal/Neurocardiogenic - most common
o
Cardiac – HIGH RISK PATIENTS, most dangerous
o
Orthostatic – “D A A D”
o
Other - Neurologic, Functional, Psych
• Work-up and Risk Stratification
o
H/P, Orthostatics, Meds, ECG, +/- Carotid Massage
o
Risk Stratify

High Risk - Admit w/ cardiac work-up

Low Risk - Outpatient workup based on frequency of episodes
• Brain Imaging ONLY if focal Neuro Deficits or Head trauma

27. Take Home Message:
• A detailed history and physical examination should be
performed in patients with syncope (Class I).
• In the initial evaluation of patients with syncope, a
resting 12-lead electrocardiogram (ECG) is useful (Class
I). Evaluation of the cause and assessment for the short-
and long-term risk of syncope is recommended (Class I).
• Hospital evaluation and treatment is recommended for
patients presenting with syncope who have a serious
medical condition potentially relevant to the cause of
syncope identified during initial evaluation (Class I).

28. Take Home Message:
• Routine and comprehensive laboratory testing is not useful in the
evaluation of patients with syncope (Class III: No Benefit). Routine
cardiac imaging is not useful in the evaluation of patients with
syncope unless cardiac etiology is suspected based on an initial
evaluation including history, physical examination, or ECG (Class
III: No Benefit). Carotid artery imaging is not recommended in the
routine evaluation of patients with syncope in the absence of
focal neurologic findings that support further evaluation (Class III:
No Benefit).
• Vasovagal syncope is the most common cause of syncope.
Effectiveness of drug therapy is modest. Patient education on the
diagnosis and prognosis is recommended (Class I).
• Dual-chamber pacing might be reasonable in a select population
of patients over 40 years of age with recurrent VVS and prolonged
spontaneous pauses (Class IIb). Beta-blockers are not beneficial in
pediatric patients with VVS (Class III: No Benefit)

29. Take Home Message:
• Syncope suspected of orthostatic hypotension (OH) can be
mediated by neurogenic conditions, dehydration, or drugs.
Fluid resuscitation by acute water ingestion or intravenous
infusion is recommended for occasional, temporary relief
in patients with neurogenic OH or dehydration (Class I).
Reducing or withdrawing medications that may cause
hypotension can be beneficial in selected patients with
syncope (Class IIa).
• In patients with syncope associated with bradycardia,
tachycardia, or in the presence of structural heart
conditions, current guideline-directed management and
therapy (GDMT) is recommended (Class I).
• Implantable cardioverter-defibrillator (ICD) implantation is
not recommended in patients with Brugada ECG pattern
and reflex-mediated syncope in the absence of other risk
factors (Class III: No Benefit)

30. Take Home Message:
• Beta-blocker therapy, in the absence of contraindications,
is indicated as a first-line therapy in patients with long QT
syndrome (LQTS) and suspected arrhythmic syncope (Class
I). ICD implantation is reasonable in patients with LQTS and
suspected arrhythmic syncope on beta-blocker therapy or
intolerant to beta-blocker therapy (Class IIa).
• Exercise restriction is recommended in patients with
catecholaminergic polymorphic ventricular tachycardia
(CPVT) presenting with syncope suspected of an arrhythmic
etiology (Class I). Beta-blockers lacking intrinsic
sympathomimetic activity are recommended in patients
with CPVT and stress-induced syncope (Class I).
• Electrophysiologic study is reasonable in selected patients
with syncope suspected of arrhythmic etiology (Class IIa).