L19: Vasovagal Syncope

Question 1

What is vasovagal syncope

Answer 1

Bradycardia
Vasodilation
Combined to give a fall in ABP and faint

Question 2

What is vasavagal syncope caused by (look at the name)

Answer 2

Increased vagal activity to the heart

Decreased SNS to the blood vessels

Question 3

When does a vasovagal syncope happen

Answer 3

Baroreflex
Exercise induced
Alerting defence response
Cortical influences

Question 4

Describe what happens in a vasovagal syncope during an alerting response

Answer 4

1) alerting repsonce leads to increased heart rate and contractility to to SNS effect on the heart
2) ventricles contract fast and very strongly with reduced EDV particular if in a standing position
3) combination leads to torsion of ventricles which stimulates mechanoreceptors of the wall of ventricles
4) afferent activity feed to medulla then to hypothalmus which evokes vasovagal syncope
6) vasovagal syncope causes an increase in PNS so heart rate decreases and vasodilation occurs as SNS activity decreases
7) there is also cortical influence that can stimulate the hypothalamus for the vasovagal syncope

Question 5

What is the clinical significance of a vasovagal syncope

Answer 5

• Occurs in extreme stress that can lead to cardiac arrest
• torsion of ventricles stimulate mechanoreceptors which can also occur in sudden large haemorrhage so you are contracting on a low EDV
• occurs following exercise because there is an increases SNS as HR increases and low EDV due to muscle vasodilation when standing up

Question 6

What is the treatment of vasovagal syncope

Answer 6

Avoid fainting trigger 
Avoid crowded places
Foot exercise 
Compression stocking 
Adequate salt intake 
Flufocortisone acetate
Pacemaker

Question 7

What does a flufocortisone acetate do

Answer 7

Expand the blood volume a little bit so blood pressure doesn’t drop below auto regulatory range