1. Syncope UCI Internal Medicine Core Curriculum - Mini Lecture
Monica Sapo, PGY2
April 2017

2. Learning Objectives Definition of Syncope Basic Etiologies of Syncope
Initial Evaluation
Risk Stratification: High vs Low Risk
Work-up & Additional Studies

3. What is Syncope?
Abrupt, transient, complete loss of consciousness, associated with inability to maintain postural tone, caused by brief period of global cerebral hypoperfusion which is by definition spontaneously self-limited.
There should not be clinical features of other non- syncopal causes of loss of consciousness

4. Non-syncopal Causes of Transient-LOC
Seizures disorders
Traumatic brain injury (i.e. concussion)
Intoxications
Metabolic disturbances (i.e. hypoglycemia)
Conversion disorders (i.e. psychogenic, pseudosyncope)
Key factor here is the underlying mechanism of syncope is presumed to be cerebral hypoperfusion, whereas nonsyncope conditions are attributed to different mechanisms.

5. Basic Etiologies of Syncope
MOST DANGEROUS
Neurally-Mediated (Vasovagal Reflex)
Situational (micturition, defecation, cough)
Prolonged standing
Crowded, hot places
During meal or post-prandial
Pain/Noxious stimuli
Fear
Carotid Sinus Hypersensitivity
Orthostatic Hypotension
Dehydration
Volume depletion/Blood loss
Autonomic insufficiency
Shy-Drager, Parkinsons, DM, adrenal insufficency
Medication-induced
Drug/Alcohol-induced
Cardiovascular
Structural
HOCM
Prolapsing atrial myxoma
Severe aortic stenosis
Arrhythmias
VT or SVT, NSVT + short or long QT interval
Bradycardias/Block/Pauses
Bifasicular block
Pacemaker/ICD malfunction
Pulmonary HTN
Pulmonary Embolus
Acute aortic dissection
Divided into 3 etiologies
Neurally mediated (i.e. vasovagal) which is most common
Orthostatic hypotension
Cardiovascular, either arrhythmic or structural which is most dangerous
MOST COMMON

6. Initial Evaluation
Purpose: To determine who is at HIGH RISK for a dangerous short-term cardiac event.
Initial Evaluation:
Detailed History & Physical Examination
Orthostatic Vitals
12-Lead ECG
*Routine laboratory testing is not indicated

7. Features More Often Associated with Cardiac Causes of Syncope: HIGH RISK
• Older age (>60 y)
• Male sex
• Presence of known ischemic heart disease, structural heart disease, previous arrhythmias, or reduced ventricular function
• Brief prodrome, such as palpitations, or sudden loss of consciousness without prodrome
• Syncope during exertion
• Syncope in the supine position
• Low number of syncope episodes (1 or 2)
• Abnormal cardiac examination
• Family history of inheritable conditions or premature sudden cardiac death (<50 y of age)
• Presence of known congenital heart disease
Table above mostly to be used as reference.
Most importantly, high risk patients are those with hx of heart disease, abnormal exam or ECG, syncope with exertion or in supine position

8. High Risk Work-up & Additional Studies
High risk patients are at high risk for for short term cardiac mortality and need appropriate cardiac work-up as an INPATIENT
Transthoracic echocardiography (TTE) if structural heart disease is suspected
Exercise stress testing in selected patients who experience syncope or presyncope during exertion
EP study in selected patients with syncope suspected of arrhythmic etiology
Head CT and/or Carotid US are not recommended in the absence of focal neurologic findings

9. Features More Often Associated with Noncardiac Causes of Syncope: LOW RISK
• Younger age
• No known cardiac disease
• Syncope only in the standing position
• Positional change from supine or sitting to standing
• Presence of prodrome: nausea, vomiting, feeling warmth
• Presence of specific triggers: dehydration, pain, distressful stimulus, medical environment
• Situational triggers: cough, laugh, micturition, defecation, deglutition
• Frequent recurrence and prolonged history of syncope with similar characteristics
Features that are associated with orthostasis or vasovagal syncope: prodromal symptoms, situational triggers, prior diagnosis, etc.

10. Low Risk Work-Up
Low risk patients are those that have no high risk characteristics or present with features highly suspicious of vasovagal or orthostatic etiology
Typically do no require hospitalization
No further work-up indicated (i.e. do not require imaging or ACS rule out)
Tilt-table testing can be used if the diagnosis is unclear after initial evaluation for suspected vasovagal syncope, delayed orthostatic hypotension, or to distinguish convulsive syncope from epilepsy
Vasovasal Syncope: Key point Reassurance and patient education on the diagnosis and prognosis
Orthostatic Hypotension: Key point Fluid resuscitation, IV or PO, If necessary, medication adjustment, Consider referral for autonomic evaluation if known or suspected neurodegenerative disease

11. Case #1
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 do we do next?

12. Case #1 Is this patient high or low risk?
HIGH RISK given recurrent episodes of syncope and exam suspicious for aortic stenosis.
What are the next steps in work-up?
Inpatient cardiac monitoring
Echocardiogram

13. Case #2
35 year old healthy male 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 do we do next?

14. Case #2 Is this patient high or low risk?
LOW RISK given age, syncope while standing, no heart disease and no other concerning features
What are the next steps in work-up?
No further work-up indicated

15. Case #3
28 year old male presents with an episode of syncope while working out at the gym. He did not experience any prodrome symptoms. This has never happened before. He has no medical history and uses no medications, drugs, or EtoH.
Patient has 3/6 systolic murmur on exam was louder with Valsalva maneuver. ECG are normal. No orthostasis. Routine labs are unremarkable.
What do we do next?

16. Case #3 Is this patient high or low risk?
HIGH RISK given abnormal cardiac exam suspicious for hypertrophic cardiomyopathy and syncope during exertion
What are the next steps in work-up?
Inpatient cardiac monitoring
Echocardiogram to evaluate for HOCM

17. Key Points
Syncope is a transient and self-limited loss of consciousness due to global cerebral hypoperfusion
Basic Etiologies include:
Vasovagal / Neurally Mediated - MOST COMMON
Orthostatic Hypotension
Cardiovascular - MOST DANGEROUS
Initial Evaluation: H&P/Orthostatics/ECG  followed by risk stratification
High Risk: Admit for further cardiac work-up
Low Risk: Outpatient management

18. References
Shen WK, Sheldon RS, Benditt DG, et al ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society. J Am Coll Cardiol 2017;Mar 9:[Epub ahead of print].
Uptodate: Syncope in adults: Clinical manifestations and diagnostic evaluation