1. Syncope Common and Uncommon Causes
Kelly Airey, MD, FACC, FHRS
Cardiology and Electrophysiology
October

2. Disclosures
- Consustant/Speaker – Biosense Webster

3. Objectives Identify causes of syncope
Identify differences between benign and malignant forms of syncope
Identify signs and symptoms which help differentiate various types of syncope

4. Definition
Syncope is a transient loss of consciousness (TLOC) resulting from global cerebral hypoperfusion, characterized by rapid onset, brevity and spontaneous recovery
EHJ. 2009;30:

5. What is the physiology? Regardless of cause:
Syncope is usually the result of cerebral hypo-perfusion
Pre-syncope is a less severe manifestation of the same process
Reduced oxygen and glucose can mimic the same condition
I tell my pts that in most cases, the cause is not fatal, it is the end result

6. Facts
The most common cause of syncope regardless of age, sex or comorbidity is vasovagal.
The second most common is cardiac.
Carotid sinus and OH rarely occur in those under 40 years
Circulation.2013;127:

7. Orhostaic Hypotensive
TLOC
Cardiac
Syncope
Orhostaic Hypotensive
Reflex
Mediated
Unknown
Non-syncope

8. Intracranial hemorrhage
Non-syncopal TLOC
Neurologic
Seizure
Stroke or TIA (RAS)
Intracranial hemorrhage
Other
Endocrine
Hypoglycemia
Psychiatric
Pulmonary Embolism

9. Hypertrophic cardiomyopathy*
Cardiac Syncope
Obstructive
Aortic stenosis
Hypertrophic cardiomyopathy*
Cardiac tumors
Arrhythmia
tachycarrhythmias
bradyarrhythmia

10. Reflex Mediated Syncope
situational
vasovagal
Carotid
Hypersensitivity

11. TLOC - Common Causes

12. What does it cost?
In the US, 30-40% are admitted at an annual cost of $2.4 billion dollars. This is related to multiple low yield investigation and unnecessary hospitalizations
Circulation.2013;127:

13. infrequent, unexplained: 38% to 47%1-4
Recurrent Syncope
infrequent, unexplained: 38% to 47%1-4
explained: 53% to 62%
500,000 new syncope patients each year5
170,000 have recurrent syncope6
70,000 have recurrent, infrequent, unexplained syncope 1-4
Studies have shown that the cause of syncope remains undiagnosed in as many as 47% of the patients who present with this symptom.
There are approximately 170,000 recurrent syncope patients in the U.S. today, meaning that up to 70,000 patients with recurrent, infrequent syncope may be going undiagnosed and therefore, improperly treated.
Of these patients, 20,000 may have undergone extensive testing with no diagnosis.
1.Kapoor W. Evaluation and outcome of patients with syncope. Medicine 1990;69:
2.Silverstein M, et al. Patients with syncope admitted to medical intensive care units. JAMA 1982;248:
3.Martin G, et al. Prospective evaluation of syncope. Ann Emerg Med 1984;13:
4.Kapoor W, et al. A prospective evaluation and follow-up of patients with syncope. N Eng J Med 1983;309:
5.National Disease and Therapeutic Index, IMS America, Syncope and Collapse #780.2; Jan 1997-Dec 1997.
6.Kapoor W, et al. Diagnostic and prognostic implications of recurrences in patients with syncope. Am J Med 1987;83:
1 Kapoor W, Med. 1990;69:
2 Silverstein M, et al. JAMA. 1982;248:
3 Martin G, et al. Ann Emerg. Med. 1984;12:
4 Kapoor W, et al. N Eng J Med. 1983;309:
5 National Disease and Therapeutic Index, IMS America, Syncope and Collapse #780.2; Jan 1997-Dec 1997.
6 Kapoor W, et al. Am J Med. 1987;83:

14. Prognosis for syncope
Prognosis is determined by the underlying etiology, specifically the presence and severity of cardiac disease. Untreated, can be >10% at 6 months
NEJM, 2002:

15. The Typical Syncopal Patient
61 years of age on average
55% are female
43% Vasovagal
14% Cardiac
43% other (including unknown)
Canadian Cardiovascular society commissioned research to streamline assessment and treatment process

16. After the ER presentation
0.7% die in 30 days
10% die within one year
7.5% will have a non-fatal severe outcome in ER (new dx, clinical deterioration, serious injury with recurrence, require therapeutic intervention)
4.5% will have a non-fatal severe outcome within 7-30 days

17. What is important
To identify and treat the 4.5% that will have a non-fatal severe outcome in the next 7-30 days after presentation.
Only a small proportion are cardiac in nature

18. Benign syncope – Cause of syncope is has good prognosis and is not life-threatening (vasovagal and other reflex-mediated) Malignant syncope – Cause of syncope is life –threatening (structural heart disease, inherited conditions; tachy/brady arrhythmias)

19. “It’s not the fall that hurts…. It’s the sudden stop at the end…
“It’s not the fall that hurts…. It’s the sudden stop at the end….” - Will Rodgers

20. Cause of Syncope Age and Risk Considerations
Young
Old
Benign
Vasovagal
Situational
Psychogenic
Orthostatic
- drugs
- multifactorial
Malignant
Inherited/Congenital disorders
causing tachycarrhythmias
- long QT
- CPVT
- ARVC
- HCM
- DCM
Arrhythmias
- bradarrhythmias
- tachycarrhythmias

21. 17 year old male presents after passing out at 4 am while urinating after waking up from a sound sleep. He was diaphoretic at the onset of urination. He woke up on the ground in the bathroom. He was alert and oriented. Long standing history of early morning light-headed episodes and syncope as a child while standing in church.

22. 17 year old male passed out at football practice
17 year old male passed out at football practice. He had just run 100 yards and started feeling light headed at 50 yds. He collapsed to the ground shortly after. Witnesses claimed that he just fell and was unresponsive for 30 seconds after with complete recovery. No seizure noted. No previous medical history.

23. 64 year old woman with long standing, poorly controlled hypertension passed out in the kitchen after gardening in 95 degree temperatures for three hours. EKG shows LVH. Last echo showed normal EF. Medications include lisinopril/hctz; metoprolol; furosemide; asa.

24. 63 year old woman passed out while sitting in a chair
63 year old woman passed out while sitting in a chair. History of anterior MI six months earlier with occluded LAD that couldn’t be opened. Class II-III heart failure symptoms with EF of 35% with anterior hypokinesis. EKG shows old anterior infarct. Medications included metoprolol, lisinopril, ASA, furosemide.

25. Hypertrophic cardiomyopathy*
Cardiac Syncope
Obstructive
Aortic stenosis
Hypertrophic cardiomyopathy*
Cardiac tumors
Arrhythmia
tachycarrhythmias
bradyarrhythmia
Reflex
Mediated
situational
vasovagal
postural hypotension

26. Vasovagal Syncope Syncope Upright posture Venous pooling
Decreased venous
return
Increased adrenergic
stimulation
Increased LV contractility
Increased LV mechanoreceptor activity
Vagal
Afferent activity
Medullary Cardioinhibitory Center
vagal
sympathetic
sympathetic
vagal
Sinus node
deceleration
Arterial
hypotension
bradycardia
Syncope
hypotension

27. Pathophysiological basis of the classification of reflex syncope. ANF
Pathophysiological basis of the classification of reflex syncope. ANF . autonomic nervous failure; ANS . autonomic
nervous system; BP . blood pressure; low periph. resist. . low
peripheral resistance; OH . orthostatic hypotension.
EHJ 2009;30:

28. Other Reflex Syncopes Carotid hypersensitivity
Postural Tachycardia Syndrome (POTS)
Primary autonomic failure

29. Situational Syncope Variant of vasovagal syncope
Recognized trigger or situation
Causal link not clear (?reflex arc)
Examples include: micturition, cough, defecation, visiting the hospital

30. Arrhythmias that Cause SyncopeVF
Polymorphic VT/Monomorphic VT
AV Block
Sinus bradycardia/pause
Hypotensive SVT

31. VF/VT Result of any one of a number of acquired or inherited disorders
Look for clinical clues to suggest the patient at risk for VT/VF

32. Causes of VT/VF Inherited Catecholaminergic polymorphic VT
Long QT syndrome
Brugada Syndrome
Hypertrophic Cardiomyopathy
Dilated Cardiomyopathy
WPW
Aquired
Ischemic Cardiomyopathy
Non-ischemic Cardiomopathy
Hypertensive
Alcoholic
Fibrosis
Infiltrative

33. 822 patients with syncope from the Framingham cohort (7814 total) followed for 17 yrs

34. Major – more than one study – minor – one study only
One major or >1 minor - should see cardiovascular specialist within two weeks

35. Clues to Suggest Malignant Cause
Lack of prodrome
History of heart disease (CAD, valvular disease, CM)
Family history of early SCD
Syncope during exercise
Abnormal EKG (WPW, Brugada, AV conduction disease, BBB)

36. Syncope and Age

37. Clinical Clues TLOC

38. EKG abnormalities
…any syncopal patient with an abnormal EKG needs further investigation

39. Syncope work up

40. 17 year old male presents after passing out at 4 am while urinating after waking up from a sound sleep. He was diaphoretic at the onset of urination. He woke up on the ground in the bathroom. He was alert and oriented. Long standing history of early morning light-headed episodes and syncope as a child while standing in church.

41. 17 year old male passed out at football practice
17 year old male passed out at football practice. He had just run 100 yards and started feeling light headed at 50 yds. He collapsed to the ground shortly after. Witnesses claimed that he just fell and was unresponsive for 30 seconds after with complete recovery. No seizure noted. No previous medical history.

42. 64 year old woman with long standing, poorly controlled hypertension passed out in the kitchen after gardening in 95 degree temperatures for three hours. EKG shows LVH. Last echo showed normal EF. Medications include lisinopril/hctz; metoprolol; furosemide; asa.

43. 63 year old woman passed out while sitting in a chair
63 year old woman passed out while sitting in a chair. History of anterior MI six months earlier with occluded LAD that couldn’t be opened. Class II-III heart failure symptoms with EF of 35% with anterior hypokinesis. EKG shows old anterior infarct. Medications included metoprolol, lisinopril, ASA, furosemide.

44. Thank you!