ECG

Question 1

Normal PR interval

Answer 1

120-200 ms (3-5 small squares)

Question 2

First degree heart block

Answer 2

Fixed prolonged PR interval where QRS complex is always present

Question 3

Second degree heart block mobitz type 1

Answer 3

Gradual prolonging of PR interval and hen a missed QRS

Question 4

Second degree heart block mobitz type 2

Answer 4

PR interval is fixed but there are dropped beats, clarify if it is 2:1, 3:1 ect

Question 5

Third degree heart block

Answer 5

No relation between QRS and P waves

Question 6

What does a short PR interval mean

Answer 6

SA node is closer to the AV node or accessory pathway e.g WPW syndrome - Delta waves

Question 7

Delta waves

Answer 7

early ventricular depolarisation e.g WPw syndrome - not diagnostic need tachy too

Question 8

two causes of broad QRS

Answer 8

Ventricular etopic and bundle branch block

Question 9

cause of tall QRS

Answer 9

Ventricular hypertrophy

Question 10

where should the transition from S > R wave to R > S wave happen?

Answer 10

V3 or V4

Question 11

What could S>R in V5 and V6 suggest?

Answer 11

Previous MI

Question 12

What does r wave progression mean?

Answer 12

small R in V1 and big R in V6

Question 13

ST elevation is significant when it is greater than 1 mm (1 small square) in

Answer 13

2 or more contiguous limb leads or >2mm in 2 or more chest leads.

Question 14

ST depression ≥ 0.5 mm in ≥ 2 contiguous leads indicates

Answer 14

myocardial ischaemia.

Question 15

T waves are tall if they are

Answer 15

> 5mm in the limb leads AND > 10mm in the chest leads (the same criteria as ‘small’ QRS complexes)

Question 16

Tall T waves can be associated with

Answer 16

Hyperkalaemia (“Tall tented T waves”)

Hyperacute STEMI

Question 17

T waves are normally inverted in

Answer 17

V1 and if in III normal variant

Question 18

if you see abnormal T wave inversion

Answer 18

Describe anatomical distribution

Question 19

Describe Biphasic T waves

Answer 19

Biphasic T waves have two peaks and can be indicative of ischaemia and hypokalaemia

Question 20

describe Flattened T waves

Answer 20

Another non-specific sign, this may represent ischaemia or electrolyte imbalance

Question 21

Describe U waves

Answer 21

The U wave is a > 0.5mm deflection after the T wave best seen in V2 or V3.

These become larger the slower the bradycardia – classically U waves are seen in various electrolyte imbalances or hypothermia, or antiarrhythmic therapy (such as digoxin, procainamide or amiodarone).

Question 22

Inferior leads

Answer 22

II, III, aVF

Question 23

Lateral leads

Answer 23

I, aVL, V5, V6

Question 24

Anterior leads

Answer 24

V3, V4

Question 25

septal leads

Answer 25

V1, V2

Question 26

Each large square on the paper represents

Answer 26

0.2 seconds

Question 27

5 large squares therefore =

Answer 27

1 second

Question 28

When the electrical activity of the heart travels towards a lead you get a

Answer 28

Positive deflection

Question 29

If the R-wave is greater than the S-wave it suggests depolarisation is moving

Answer 29

Towards the lead

Question 30

Right axis deviation (RAD) is usually caused by

Answer 30

right Ventricular hypertrophy

Question 31

RAD is associated with what group of conditions?

Answer 31

Pulmonary disease - increased right sided heart strain

Question 32

LAD is usually caused by

Answer 32

conduction defects and not by increased mass of the left ventricle.