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Cardiovascular system > Syncope > Flashcards

Syncope Flashcards

1
Q

Define syncope

A

transient loss of consciousness due to global cerebral hypoperfusion

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2
Q

3 features of syncope

A

rapid onset
short duration
spontaneous complete recovery

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3
Q

What causes transient loss of consciousness?

A

Traumatic - head injury

Non-traumatic:
- global cerebral hypoperfusion (syncope)
- not due to global cerebral hypoperfusion (epilepsy, psychogenic, hypoglycaemia, hypoxia, toxins, subarachnoid haemorrhage, vertebrobasilar TIA)

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4
Q

Causes of syncope

A

reflex
orthostatic
cardiac
unknown

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5
Q

What are the 3 types of reflex syncope?

A

vasovagal
situational
carotid sinus syndrome

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6
Q

What ages does reflex syncope affect?

A

any age (more common in younger + elderly)

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7
Q

What does reflex syncope occur in response to?

A

a trigger
- emotional stress or real/threatened/imagined injury (eg. due to pain, sight of blood)

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8
Q

What position is reflex syncope most common in?

A

standing up

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9
Q

What are the symptoms just before a syncopal episode?

A

usually a prodrome lasting 30 secs - several mins
fatigue
yawns
hot
sweaty
nauseous
dimming of vision

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10
Q

How does a patient appear during a syncopal episode?

A

pale
diaphoretic

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11
Q

How does vasovagal syncope occur?

A

pain/emotional trigger
exaggerated sympathetic activation
circulating hypovolaemia
activation ventricular afferents

brainstem:
- sympathetic withdrawal –> vasodilation –> hypotension –> syncope
and/or
- increased vagal tone –> bradycardia –> syncope

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12
Q

Common triggers of vasovagal syncope

A

pain
fear
prolonged standing
having blood taken

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13
Q

What is situational syncope?

A

a form of reflex syncope caused by specific triggers

micturition syncope = fainting occurring shortly after or during urination
mainly occurs in men

some triggers = micturition, defaecation, coughing, laughing, swallowing

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14
Q

Describe the carotid sinus reflex

A

carotid sinus = a dilatation at the base of the internal carotid artery that contains baroreceptors which monitor BP

increased BP = stretches carotid baroreceptors = send messages to brain stem:
- increase parasympathetic activity (decrease HR + contractility), decreases CO, decreases BP (BP = TPR x CO)

  • decrease sympathetic activity (vasodilatation), decreases total peripheral resistance, decreases BP
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15
Q

What is carotid sinus massage and what is a normal response?

A

bedside test to test the carotid sinus reflex
normal response = slight drop in HR and/or BP
exaggerated response occurs in carotid sinus sensitivity

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16
Q

What is carotid sinus syndrome?

A

syncope without warning and exaggerated carotid sinus massage response with reproduction of syncope

mainly in older men
pacing can help if carotid sinus massage mainly causes bradycardia

17
Q

Carotid sinus syndrome triggers

A

head turning
shaving
tight collars

18
Q

What is orthostatic hypotension?

A

standing from a supine position causes roughly 10-15% blood volume to be redistributed to the abdomen and lower limbs, reducing venous return and cardiac output
without compensatory mechanisms, BP would drop
can cause syncope, dizziness on standing or falls

19
Q

How is orthostatic hypotension defined?

A

decrease in systolic Bp of >=20mmHg (or diastolic >=10mmHg) within 3 mins of standing
OR
decrease in systolic BP <90mmHg

20
Q

What is the normal physiology of orthostasis

A

decreased stretch of carotid sinus
decreased baroreceptor traffic
increase sympathetic activity
decrease parasympathetic activity
increased vasoconstriction
increased HR
increased contractility

21
Q

What drugs can make orthostatic hypotension more likely?

A

anti-hypertensives
anti-anginals
anti-BPH (benign prostatic hyperplasia)
anti-depressants
anti-psychotics
anti-parkinsonian
alcohol

22
Q

What are some causes of hypovolaemia that can make orthostatic hypotension more likely?

A

dehydration
Addison’s disease

23
Q

What causes of autonomic failure can make orthostatic hypotension more likely?

A

primary = Parkinson’s
secondary = aging, diabetes

24
Q

What features suggest orthostatic hypotension?

A

symptoms are worse:
- on standing
- in the morning
- after meals
- after exercise
- in hot environments

symptoms are better:
- when lying/sitting

25
Q

Management of reflex syncope and orthostatic hypotension

A

reassurance
education
lifestyle changes
stop/reduce BP lowering drugs

still symptomatic = counter-pressure manoeuvres

selected patients:
- low BP = fludrocortisone, midodrine
- slow HR = pacing

26
Q

When should pacing be considered for syncope?

A

recurrent syncope despite medical therapy
+ bradycardia or asystolic pauses

27
Q

What causes cardiac syncope?

A

arrhythmia:
- bradycardia = sinus node disease, AV block
- tachycardia = VT, SVT

structural:
- cardiac = aortic stenosis, ACS, cardiomyopathy
- vascular = PE, aortic dissection

28
Q

Syncope red flags

A

symptoms:
- on exertion
- supine
- no warning

PMH:
- structural heart disease
- coronary artery disease
- heart failure

FH:
- sudden cardiac death

other symptoms:
- chest pain
- palpitations
- SOB
- abdominal pain
- headache

examination:
- low BP
- slow HR
- undiagnosed systolic murmur

abnormal ECG

29
Q

Key points in a syncope history (6Ps)

A

provoking factors
posture
prodrome
PMH/DH/FH
Passerby account
Post event

30
Q

Key points in examination in syncope

A

heart rate - rate + rhythm
lying + standing BP
carotid sinus massage
systolic murmur (aortic stenosis, hypertrophic cardiomyopathy)

31
Q

What investigations can be carried out for syncope?

A

ECG

ECHO - if structural heart disease suspected

Cardiac rhythm monitoring:
- Holter - frequent symptoms + arrhythmic cause suspected
- Loop recorder - infrequent cause and arrhythmic cause suspected

Tilt Test - syncope of unknown cause where reflex syncope is suspected

Cardiovascular system (33 decks)

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