Clinical Skills: ECG Interpretation

Question 1

W. is the value of 1 small box (horizontal) on a ECG paper?

Answer 1

0.04s

Question 2

W. is the value of 1 large box (horizontal) on a ECG paper?

Answer 2

0.20s

Question 3

W. is the value of 1 large box (vertical) on a ECG paper?

Answer 3

0.5mV

Question 4

Explain the importance of ECG paper. (1)

Answer 4

Helps calculate heart rate:
- every 3 seconds (15 boxes) marked with vertical line.

Question 5

W. are the 5 steps of rhythm analysis? (5)

Answer 5

Calculate rate:
- Count the no. of R waves in a 6 second rhythm strip then x 10.

Determine regularity:
- Look at the R-R distance (using a caliper or markings on a pen/paper)
- Regular (are they equal distant apart?), Occassionally irregular?, Regularly irregular? Irregularly irregular?

Assess P waves:
- Are there P waves?
- Do the P waves look alike?
- Do the P waves occur at a regular rate?
- Is there one P wave before each QRS?

Determine PR interval:
- Normal = 0.12-0.20 sec (3-5 boxes)

Determine QRS duration:
- Normal = 0.04-0.12 sec (1-3 boxes)