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CIDR/FoCP > ECG > Flashcards

Flashcards in ECG Deck (31):
1

PR segment - when?

End of P to beginning of R

2

ST segment - when?

S to beginning of T

3

QT interval - when?

Start of Q - end of T

4

P wave - what?

Atrial depolarisation

5

QRS complex - what?

Ventricular depolarisation

6

T wave - what?

Ventricular repolarisation

7

Placement of limb leads

Red - right arm
Yellow - left arm
Green - left leg
Black - right leg

8

Septal view

V1, V2

9

Anterior view

V3, V4

10

Lateral view

V5, V6, I, aVL (aVR)

11

Inferior view

II, III, aVF

12

V1, V2

Septal

13

V3, V4

Anterior

14

V5, V6, I, aVL, (aVR)

Lateral

15

II, III, aVF

Inferior

16

Calculate rate

300/number of large squares between R-R complexes

17

Sinus rhythm

Exactly same distance between each QRS
Each P wave followed by a QRS complex
Each QRS complex preceded by a P wave

18

Normal cardiac axis

I ↑
II ↑ (by largest amount)
III ↑ or ↓
(aVR most ↓)

19

Right axis devation

Usually caused by right ventricular hypertrophy
Extra heart muscle causes stronger single to be generated by right side of heart
Can be normal in very tall individuals
I ↓
II ↑ (more than normal)
III ↑ (more than normal)

20

Left axis deviation

Usually caused by conduction defects
I ↑
II ↓
III ↓

21

PR interval

Start of P to first deflection of QRS
Normal is 3-5 small squares (0.12-0.2s)
Represents conduction time of AV node
Prolonged = 1st degree heart block

22

1st degree heart block

Conduction of AV node is slowed, but gets through
Prolonged PR

23

2nd degree heart block Mobitz I

Progressive prolongation of PR interval culminating in missing QRS complex

24

2nd degree heart block Mobitz II

Intermittent missing QRS complexes without progressive prolongation of PR interval
PR interval in conducted beats remains constant
P waves constant rate

25

3rd degree heart block

No relationship between P waves and QRS complexes
Two independent rates
Severe bradycardia

26

ORS complex

Normal <3 small squares (0.12s)
Broad complex = either conduction delay (bundle branch block) or rhythm arising from the ventrical (VT/VF/heart block)

27

Q waves

Downward deflection before the R wave
Pathological Q waves:
• >2 small squares deep
• > 1 small square wide
• >25% of height of R wave
Previous MI
NB. Normal in V1

28

R waves

R wave height progresses across precordial height
Poor R wave progression suggests old anterior infarct

29

ST segment

Should be isoelectric
Elevated suggests MI
Depressed suggests ischaemic myocardial tissue in the vantricles

30

T waves

Ventricular repolarisation
Upright in all leads except aVR, V1 (and V2?)
Can get inversion or big broad ones

31

ECG changes in STEMI

Earliest sign is increase in T wave amplitude
T wave pinted
ST elevation follows
Later - development of Q waves
Right sided leads in patients with inferior MI
Posterior - ST depression V1-V3 and dominant R wave V1