How to ECG

Question 1

1. Basic checks

Answer 1

patient details, speed, adequacy of trace

Question 2

2. Rate

Answer 2

1500 divided by R-R interval in small squares

Question 3

3. Rythm sinus?

Answer 3

P wave precedes every QRS

PR interval consistent and 3-5 small squares wide

Question 4

P waves

Answer 4

3 small square wide

2.5 tall

Question 5

QRS Complex

Answer 5

<3 small square wide

At least 1 large square tall

Question 6

Cardiac Axis

Answer 6

QRS in leads 1, 2 & 3 should all be upgoing

Question 7

ST segment

Answer 7

Horizontal and isoelectric

Question 8

QT interval

Answer 8

< 2.25 large squares

Question 9

T waves

Answer 9

Should be up-going in most leads
Should be inverted in aVR and 3
Can be non-pathologically inverted in V1 (which may be accompanied by inversion in V2)