this lecture explains Syncope which is a transient loss of consciousness from many points: the definition, causes, next step, history and physical examination from evidence based resources as the UpToDate and the European society of cardiology guidelines 2018.

1. Syncope
Background & Approach
Prepared by: Khaled Alkhodari

5. Definitions
• Syncope is ………………..

6. Definitions
• Syncope is defined as TLOC due to cerebral hypoperfusion,
characterized by:
• a rapid onset,
• short duration,
• and spontaneous complete recovery.
• Syncope shares many clinical features with other disorders; it
therefore presents in many differential diagnoses. This group of
disorders is labelled TLOC

7. • TLOC is defined as a state of real or apparent LOC with loss of
awareness, characterized by
• amnesia for the period of unconsciousness,
• abnormal motor control,
• loss of responsiveness,
• and a short duration.
• The two main groups of TLOC are ‘TLOC due to head trauma’ and
‘non-traumatic TLOC’

8. • The adjective presyncope is used to indicate symptoms and signs that
occur before unconsciousness in syncope.
• Note that the noun presyncope is often used to describe a state that
resembles the prodrome of syncope, but which is not followed by
LOC.

10. Classification and pathophysiology of
syncope and TLOC
• The pathophysiological classification centres on a fall in systemic
blood pressure (BP) with a decrease in global cerebral blood flow as
the defining characteristic of syncope.
• A sudden cessation of cerebral blood flow for as short as 6–8 s can
cause complete LOC.
• A systolic BP of 50–60 mmHg at heart level, i.e. 30–45 mmHg at brain
level in the upright position, will cause LOC.

12. • There are three primary causes of a low total peripheral resistance.
• The first is decreased reflex activity causing vasodilatation through withdrawal
of sympathetic vasoconstriction: this is the vasodepressive type’ of reflex
syncope.
• The second is a functional impairment of the autonomic nervous system
• The third a structural impairment of the autonomic nervous system.
• In autonomic failure, there is insufficient sympathetic vasoconstriction in response to the
upright position.

13. • There are four primary causes of low cardiac output.
• The first is a reflex bradycardia, known as cardioinhibitory reflex syncope.
• The second concerns cardiovascular causes: arrhythmia, structural disease
including pulmonary embolism, and pulmonary hypertension.
• The third is inadequate venous return due to volume depletion or venous
pooling.
• Finally, chronotropic and inotropic incompetence through autonomic failure
may impair cardiac output.

18. Caution:
There are some conditions that present with
TLOC but are not syncope

20. Diagnostic evaluation and management
according to risk stratification
1. Was the event TLOC?
2. In case of TLOC, is it of syncopal or non-syncopal origin?
3. In case of suspected syncope, is there a clear aetiological diagnosis?
4. Is there evidence to suggest a high risk of cardiovascular events or
death?

22. • TLOC has four specific characteristics:
• TLOC is probably syncope when:

23. • TLOC has four specific characteristics: short duration, abnormal
motor control, loss of responsiveness, and amnesia for the period of
LOC.
• TLOC is probably syncope when:
1. There are signs and symptoms specific for reflex syncope,
syncope due to OH, or cardiac syncope.
2. Signs and symptoms specific for other forms of TLOC (head
trauma, epileptic seizures, psychogenic TLOC, and/or rare causes)
are absent.

27. • Algorithm representing the
emergency department
approach to an adult patient
with syncope

30. Life-threatening conditions
• The most important causes to consider are: cardiac syncope, blood loss,
pulmonary embolism, and subarachnoid hemorrhage. Other conditions, such as
seizure, stroke, and head injury, do not meet the technical definition of syncope
but should be considered during the initial assessment.
• Cardiac syncope – Cardiac causes are the most common life-threatening
conditions associated with syncope and thus the most important to diagnose or
predict. They include arrhythmia, ischemia, structural/valvular abnormalities (eg,
aortic stenosis), cardiac tamponade, and pacemaker malfunction.
• Hemorrhage – Large blood loss, particularly acute severe hemorrhage, can
manifest as syncope. Important potential causes include: trauma, gastrointestinal
bleeding, ruptured aortic aneurysm, ruptured ovarian cyst, ruptured ectopic
pregnancy, and ruptured spleen.
• Pulmonary embolism – Hemodynamically significant pulmonary embolism is a
relatively uncommon but well documented and important cause of syncope.
• Subarachnoid hemorrhage – Patients presenting with syncope associated with
headache require evaluation for a possible subarachnoid hemorrhage.

37. Management of syncope in the emergency
department based on risk stratification
• The management of TLOC of suspected syncopal nature in the ED
should answer the following three key questions:
1. Is there a serious underlying cause that can be identified?
2. What is the risk of a serious outcome?
3. Should the patient be admitted to hospital?

50. Diagnostic tests

51. Orthostatic challenge
• Changing from the supine to the upright position produces a
displacement of blood from the thorax to the lower limbs and
abdominal cavity that leads to a decrease in venous return and
cardiac output. In the absence of compensatory mechanisms, a fall in
BP may lead to syncope.
• Currently, there are three methods for assessing the response to
change in posture from supine to erect: active standing , head-up tilt,
and 24-h ambulatory BP monitoring (ABPM).

56. TREATMENT

63. Syncope in patients with comorbidity and
frailty

64. PPS (psychogenic pseudosyncope)

65. Epilepsy

67. ECG
Test YourSelf

79. ECG 1

80. ECG 2

88. Key messages
Diagnosis: initial evaluation
• (1) At the initial evaluation answer the following four key questions: Was the
event TLOC? In cases ofTLOC, are they of syncopal or non-syncopal origin? In
cases of suspected syncope, is there a clear aetiological diagnosis? Is there
evidence to suggest a high risk of cardiovascular events or death?
• (2) At the evaluation of TLOC in the ED, answer the following three key
questions:
• Is there a serious underlying cause that can be identified?
• If the cause is uncertain, what is the risk of a serious outcome?
• Should the patient be admitted to hospital?

89. • 3) In all patients, perform a complete history taking, physical examination (including
standing BP measurement), and standard ECG.
• (4) Perform immediate ECG monitoring (in bed or telemetry) in highrisk patients when
there is a suspicion of arrhythmic syncope.
• (5) Perform an echocardiogram when there is previous known heart disease, or data
suggestive of structural heart disease or syncope secondary to cardiovascular cause.
• (6) PerformCSM in patients >40 years of age with syncope ofunknown origin compatible
with a reflex mechanism.
• (7) Perform tilt testing in cases where there is suspicion of syncope due to reflex or an
orthostatic cause.
• (8) Perform blood tests when clinically indicated, e.g. haematocrit and cell blood count
when haemorrhage is suspected, oxygen saturation and blood gas analysis when hypoxic
syndromes are suspected, troponin when cardiac ischaemia-related syncope is
suspected, and Ddimer when pulmonary embolism is suspected, etc.

90. Diagnosis: subsequent investigations
• 9. Perform prolonged ECG monitoring (external or implantable) in
• patients with recurrent severe unexplained syncope who have all of the following
three features: Clinical or ECG features suggesting arrhythmic syncope. A high
probability ofrecurrence of syncope in a reasonable time. Who may benefit from
a specific therapy if a cause for syncope is found.
• 10. Perform EPS in patients with unexplained syncope and bifascicular BBB
(impending high-degree AV block) or suspected tachycardia.
• 11. Perform an exercise stress test in patients who experience syncope during or
shortly after exertion.
• 12. Consider basic autonomic function tests (Valsalva manoeuvre and deep-
breathing test) and ABPM for the assessment of autonomic function in patients
with suspected neurogenicOH.
• 13. Consider video recording (at home or in hospital) of TLOC suspected to be
ofnon-syncopal nature.