Syncope - 113

Question 0

How do you calculate mean arterial pressure?

Answer 0

Diastolic bp + the difference between diastolic and systolic / 3

e.g. if the bp is 120/80 mean arterial pressure will be: 80+40/3

Question 1

What is vasovagal syncope most commonly due to?

Answer 1

Over heating

Question 2

What is the difference in compliance between veins and arteries?

Answer 2

Compliance of arteries is ~20x LOWER than that of veins

Question 3

What causes arterial pressure?

Answer 3

Cardiac output x total peripheral resistance

Question 4

Where does the main drop in bp occur?

Answer 4

Arterioles

Question 5

What is the primary cause of syncope?

Answer 5

Cardiac arrhythmias

Question 6

When would you worry about syncope?

Answer 6

If it is exertional, history of SOB, family history of cardiac disease, murmur, abnormal ECG

Question 7

Describe the pulmonary circuit

Answer 7

Blood leaves the R ventricle and enters the pulmonary artery, branching left or right into the lungs. Once oxygenated it returns to the left atrium

Question 8

How long is a normal PR interval?

Answer 8

120-200ms

Question 9

How long is a normal QRS complex? Give an example of a reason it could be longer than this.

Answer 9

120ms

Would be longer in bundle branch block and third degree heart block.

Question 10

What is first degree heart block?

Answer 10

Characterised by delay at the AVN and Bundle of His. It is not normally a problem but can indicate coronary artery disease or other cardiac disorders.

Question 11

What are the 2 types of 2nd degree heart block? How are they different?

Answer 11

Wenckebach/Mobitz type I: AVN block, usually benign. PR lengthens until a P isn’t followed by a QRS.
Mobitz type II: Bundle of His block. PR intervals normal length, QRS complexes dropped at random. Usually signifies serious heart disease.

Question 12

What is 3rd degree heart block? How is it treated?

Answer 12

Atrio-ventricular dissociation. Ventricles generate ‘escape rhythm’. QRS complex is wide, it is usually due to a degenerative disease of the conductance system. It is a medical emergency and needs a pacemaker.

Question 13

What can cause left bundle branch block? Is it significant?

Answer 13

Left bundle branch block is always pathological (whereas right is often normal). It can be caused by IHD and causes a widening of the QRS complex

Question 14

What could right and left axis deviation be due to?

Answer 14

RIGHT - Pulmonary conditions and congenital heart disorders.

LEFT - a conduction defect

Question 15

Splaying of the carina can sometimes be seen on X-ray. What does it suggest?

Answer 15

Left atrial enlargement