Reading an ECG

Question 1

What is a normal heart rate ?

Answer 1

60-100 bpm

Question 2

Which leads do you look at to assess axis deviation ?

Answer 2

Leads I and II

Question 3

Which section of a heart wave do you look at to assess axis deviation ?

Answer 3

The QRS complex

Question 4

What does a left axis deviation look like on ECG ?

Answer 4

QRS positive (pointing up) in lead I
QRS negative (pointing down) in lead II

using the thumb method, the thumb pointing up is the side of the deviation

Question 5

What does a right axis deviation look like on ECG ?

Answer 5

QRS negative (pointing down) in lead I
QRS positive (pointing up) in lead II

using the thumb method, the thumb pointing up is the side of the deviation

Question 6

What does Left Vs Right atrial hypertrophy look like?

Answer 6

Left atrial hypertrophy = m shaped P wave = “p mitrale”

Right atrial hypertrophy = pointed p wave = “p pulmonale”

Question 7

What is a normal QRS duration ?

Answer 7

0.12 secs or less

Question 8

What is considered a wide QRS duration ?

Answer 8

> 0.12 secs

Question 9

What could a wide QRS indicate ?

Answer 9

• bundle branch block
• ventricular hypertrophy
• HF
• MI

Question 10

What morphology does a really tall/large QRS indicate ?

Answer 10

Left ventricular hypertrophy

Question 11

What does an ST elevation/depression indicate ?

Answer 11

MI

stemi/nstemi

Question 12

What does an ST elevation look like on ECG ?

Answer 12

ST segment (between QRS and T wave) elevated above baseline

Question 13

What does an ST depression look like on ECG ?

Answer 13

ST segment (between QRS and T wave) dropped below baseline

Question 14

What does a small T wave indicate ?

Answer 14

Hypokalaemia

Question 15

What does a tall/tented T wave indicate ?

Answer 15

Hyperkalaemia

Question 16

What does an inverted/biphasic T wave indicate ?

Answer 16

Ischaemia or Precious infarct

Question 17

How long is a normal QT interval ?

Answer 17

<400ms

Question 18

What are the 3 main signs of Hyperkalaemia on ECG ?

Answer 18

• tall, tented T waves
• wide QRS
• flattened P waves

might see all 3 together, might not

Question 19

Which leads can you ignore in an ECG ?

Answer 19

aVR

Question 20

How does pericarditis show on ECG ?

Answer 20

General changes across all leads

Question 21

Which leads does MI show up on ECG ?

Answer 21

Regional changes to specific leads depending which region of heart is affected = indicates where the MI occurred

Question 22

Which leads on an ECG do you look at to assess bundle branch block ?

Answer 22

V1 and V6

Question 23

What does the QRS in Left bundle branch block look like on ECG ?

Answer 23

Broad QRS with…
V1 = W shaped QRS
V6 = M shaped QRS

(the changes are seen at the tip of R)

Question 24

What does the QRS in Right bundle branch block look like on ECG ?

Answer 24

Broad QRS with…
V1 = M shaped QRS
V6 = W shaped QRS

(the changes are seen at the tip of R)

Question 25

What ECG findings are suspicious of coronary artery disease ?

Answer 25

• ST elevation / depression
• T wave abnormalities (inversion or tall)
• wide/deep QRS complex
• Left bundle branch block

Question 26

What are the characteristics of left bundle branch block on ECG ?

Answer 26

• broad QRS (>0.12secs)
• V1=W, V6=M shaped QRS
• deep S wave in V1
• no Q wave in V5/6