ECGs

Question 1

What are the 12 steps of interpreting an ECG?

Answer 1

1. Patient details
2. Date and time of ECG
3. Paper speed, calibration
4. Rate
5. Rhythm
6. Axis
7. P wave
8. PR
9. QRS
10. ST
11. T wave
    12 Other (QTc and U waves)

Question 2

What should the paper speed be?

Answer 2

25mm/s

Question 3

What should the voltage calibration be?

Answer 3

1cm/mV or 2 large squares

Question 4

How do you calculate rate

Answer 4

Count 30 big squares and number of R waves in that time x10
OR
300 / no. big squares in R-R

Question 5

Which leads do you look at in axis deviation?

Answer 5

I, II, III

Question 6

Which lead is most positive in normal heart? What do the other two show?

Answer 6

II

Other two are also positive

Question 7

In right axis deviation what ECG changes are there?

Answer 7

Lead I negative

II and III positive

Question 8

In left axis deviation what ECG changes are there?

Answer 8

Lead I positive

II and III negative

Question 9

Where is lead I ?

Answer 9

Left side

Question 10

Which leads show the anterior heart?

Answer 10

v1-v4

Question 11

Which leads show the inferior heart?

Answer 11

aVF, II, III

Question 12

Which leads show the left lateral heart?

Answer 12

aVL, v5, v6, I

Question 13

Which leads show the right atrium?

Answer 13

aVR, v1

Question 14

How big should a P wave be?

Answer 14

> /= 2 small squares

Question 15

Bifid P wave indicates?

Answer 15

L atrial hypertrophy

Question 16

Peaked P wave indicates?

Answer 16

R atrial hypertrophy

Question 17

How long should PR interval be?

Answer 17

3-5 small squares

Question 18

Abnormal PR interval can indicate what?

Answer 18

Heart block

Question 19

PR int. of >5ss =?

Answer 19

1st degree heart block

Question 20

Progressively longer PR int until a beat is skipped

Answer 20

2nd degree HB, Mobitz type 1 (or Wenkebach)

Question 21

Normal PR int but with some beats skipped

Answer 21

Mobitz type 1 (second degree HB)

Question 22

Complete dissociation between P waves and QRS complex

Answer 22

3rd degree HB

Question 23

What should the length of the QRS be?

Answer 23

<3 ss

Question 24

Increased QRS =?

Answer 24

Bundle branch block

Question 25

What does RBBB look like?

Answer 25

On v1 and v6 the deflections repel (MaRRoW)

Question 26

What does LBBB look like?

Answer 26

WiLLiaM on v1 and v6

Question 27

What would you see in WPW syndrome?

Answer 27

delta waves and a short PR interval

Question 28

What do you look for in the ST segment?

Answer 28

Elevation >1ss (infarction) and depression >1ss (ischaemia or posterior infarction)

Question 29

ST changes in leads II, III and aVF is which artery?

Answer 29

Right coronary

Question 30

ST changes in leads v1-v4 is which artery?

Answer 30

Left anterior descending

Question 31

ST changes in leads aVL, v5, v6 and I is which artery?

Answer 31

Left circumflex

Question 32

The reverse tick is where in the cardiac cycle and indicates what?

Answer 32

ST, digoxin toxicity

Question 33

Tented T wave=

Answer 33

hyperkalaemia

Question 34

Flat T wave-

Answer 34

hypokalaemia

Question 35

Inverted T wave=

Answer 35

Normal in III, aVR and v1, otherwise could be ischaemia

Question 36

What QTc interval is ABnormal? What does this indicate?

Answer 36

>450ms predisposition to polymorphic VT

Question 37

What do U waves indicate?

Answer 37

Normal or hypokalaemia