Basic EKG Interpretation Part 2

Question 1

What is the idea behind the EKG changes seen in BBB?

Answer 1

Conduction is fast down the branch without the block and then overflows into the chamber in which the block occurred

Question 2

What EKG changes are seen in BBB?

What is the difference between these changes in RBBB and LBBB?

Answer 2

Split R –> R,S,R’
Inverted T wave
QRS > 120 ms

Changes take place in the leads corresponding to the side of the heart where the block is, e.g.:

• -RBBB - look at V1, avR
• -LBBB - look at V5, V6, I

Question 3

First degree heart block

–what is expected from an EKG trace

Answer 3

Fixed PR prolongation

All P waves make it to QRS, just get there slower

Question 4

Second degree heart block, Type 1

• aka
• EKG changes

Answer 4

Wenchebach

Gradual PR prolongation – until AV node doesn’t conduct
We see GROUPED beating

Question 5

Second degree heart block, Type 2

-EKG

Answer 5

Unpredictable AV block

Usually this occurs with a sick electrical system, so you should look for other EKG changes
–normally also find LBBB or RBBB

Question 6

The most common cause for a pause is …

Answer 6

a nonconducting P wave

This means the P wave comes too early (before the ventricle has repolarized) and therefore, no QRS

Question 7

Third degree heart block

Answer 7

AV dissociation