ECG axis

Question 1

What would a prolonged PR interval represent on ECG?

Answer 1

Heart block

A PR interval longer than 0.20 seconds is considered heart block

Question 2

What is the significance of a right sided change in the axis?

Answer 2

PE

Question 3

What is the significance of a left sided change in the axis?

Answer 3

Conduction deficit

Question 4

What can cause left axis deviation? (2 things)

Answer 4

1. Left ventricle hypertrophy

2. Right ventricular damage

Question 5

What can cause right axis deviation? (2 things)

Answer 5

1. Right ventricle hypertrophy

2. Left ventricular damage

Question 6

What is the ECG axis?

Answer 6

The average direction of electrical movement through the heart

Question 7

What is meant by poor R wave progression?

What could this mean? (5 things)

Answer 7

• Refers to whether or not the QRS is predominantly positive or negative.
• Poor progression is where the R wave does not increase in size in leads V1-V6

Causes:

• Poor lead placement
• Old anteroseptal MI
• LVH or RVH
• Cardiomyopathy
• LBBB

Question 8

In R wave progression should leads 1+2 be positive, negative or isoelectric?

Answer 8

Negative

Question 9

In R wave progression should leads 3+4

be positive, negative or isoelectric ?

Answer 9

They should be Isoelectric

But note:
V4 will often be positive

Question 10

In R wave progression should leads 5+6 be positive, negative or isoelectric?

Answer 10

Positive