Heart Block

Question 1

What is first degree heart block?

Answer 1

When the conduction of the impulse from the SAN to the AV node is delayed

Question 2

What is a sign of first degree heart block?

Answer 2

Prolonged PR interval

Question 3

What are the two classifications of second degree heart block?

Answer 3

Mobitz 1

Mobitz 2

Question 4

What is the ECG sign of a Mobitz 1 heart block?

Answer 4

The PR interval gets progressively longer, and then drops, so you ‘skip a beat’

Question 5

You usually don’t require treatment for which types of heart block?

Answer 5

First degree (asymptomatic) 
Second degree Mobitz 1 (benign)

Question 6

What is the consequence of Mobitz 2 heart block? What treatment does it need?

Answer 6

Severe bradycardia and progression to third degree heart block?
Pacemaker

Question 7

What is the sign of Mobitz 2 heart block?

Answer 7

It alternates between normal PR intervals and then dropped beats

Question 8

What is third degree heart block?

Answer 8

When the impulse from the SAN node no longer progresses through to the AV node, so the ventricles start generating impulses themselves and you get AV dissociation as the atria and ventricles contract at different times.

Question 9

What do you call it when the ventricles generate impulses themselves?

Answer 9

Automaticity

Question 10

What do you call the ventricles’ independent rhythm in third degree heart block?

Answer 10

Ventricular escape rhythm

Question 11

What is the consequence of third degree heart block?

Answer 11

Sudden death

Syncope

Question 12

What would you see on an ECG for someone with third degree heart block?

Answer 12

Their p waves and QRS complexes will have nothing to do with each other

Question 13

What would the atrial rate be of someone with third degree heart block?

Answer 13

60-100bpm

Question 14

What would the ventricular rate be of someone with third degree heart block?

Answer 14

Half of the atrial rate, so around 30-45bpm (it can only do half the job)