9. a. Syncope

Question 1

What is syncope?

Answer 1

Transient loss of consciousness due to global brain hypoperfusion

Question 2

What conditions need to be met for an event to be considered true syncope?

Answer 2

Rapid onset
Short duration
Inability to maintain postural tone
Spontaneous complete recovery

Question 3

What is pre-syncope?

Answer 3

Feeling of faintness without loss of consciousness

Question 4

What are the causes of syncope?

Answer 4

Vasovagal syncope
Carotid sinus syndrome
Orthostatic hypotension
Arrhythmias
Structural CV disease

Question 5

Describe the process of vasovagal syncope

Answer 5

Standing causes a reduction in venous return and cardiac output
Reduces the stimulation of baroreceptors in carotid sinus
LV hypercontracts in response to the low CO, activating mechanoreceptors in the ventricle which feed back to the medulla in the vagus
This causes an inappropriate reduction in sympathetic tone and an increase in parasympathetic tone
The resulting hypotension and bradycardia causes syncope

Question 6

What medications could be responsible for syncope?

Answer 6

Antihypertensives
Antianginals
QT prolongers
Proarrhythmic

Question 7

What is a Holter monitor?

Answer 7

Monitors the heart for 24 hours

Question 8

What special investigations can be done into syncope?

Answer 8

Head-up tilt table test
Carotid sinus massage
Pacemaker check
EP study

Question 9

What are the contraindications for a carotid sinus massage?

Answer 9

Carotid bruit
Known carotid artery disease
TIA/stroke in past 2 months

Question 10

How is a carotid sinus massage done?

Answer 10

Monitor rhythm and BP for 5-10 seconds while massaging

Question 11

What is a positive result for a carotid sinus massage?

Answer 11

Cardiac asystole for 3+ seconds or a drop in BP

Positive test means carotid sinus syndrome can be diagnosed

Question 12

What are the structural CV causes of syncope?

Answer 12

MI
Hypertrophic cardiomyopathy
Aortic dissection
Valvular abnormalities

Question 13

Which bradyarrhythmias cause syncope?

Answer 13

Sinus arrest

AV block

Question 14

Which tachyarrhythmias cause syncope?

Answer 14

Atrial fib/flutter
Paroxysmal (supra) ventricular tachycardia
Torsade de Pointes

Question 15

How should syncope be managed?

Answer 15

Treat the underlying cause

Medications should be given as a last resort for recurrent episodes (fludrocortisone increases Na)

Question 16

What specific management should be given for vasovagal syndrome?

Answer 16

Avoid triggers, identify warning signs
Improve fluid intake
Compression stockings