[ECG made easy][ECG 1st principles]

Answer 1

I, II, III, VR, VL, VF

Answer 2

V1-V6

Answer 3

Right leg lead

Answer 4

VL
I
II

Answer 5

VF

III

Answer 6

VR

Answer 7

Right ventricle

Answer 8

septum

anterior wall of left ventricle

Answer 9

Anterior wall of left ventricle

Lateral wall of left ventricle

Answer 10

Whichever shows the P wave most clearly (usually II)

Answer 11

Depolarisation towards a lead

so in V5+V6 ventricular depolarisation causes just o positive deflection. No classic ‘R’ deflection

Answer 12

towards

and vice versa - if the R and S waves are of equal size = depolarisation at right angles to the lead

Answer 13

The depolarisation wave spreads from 11 to 5 o’clock

i.e. away from VR and towards II as seen from the front

Answer 14

Cardiac axis

Answer 15

I
II (will have the biggest +ve deflection in normal axis)
III

*predominantly +ve deflections will be seen

Answer 16

I: -ve
II: +ve but less so
III: +ve increased and more than II

Answer 17

it is the predominant deflection that must be taken into account

Answer 18

lead II becomes predominantly -ve

(and lead III must be as well, obviously)

*usually due to conduction defect

Answer 19

0

Answer 20

90

Answer 21

60

Answer 22

120

Answer 23

-30

Answer 24

-150

Question 25

[ECG 1st principles]: what is the normal cardiac angle

Answer 25

-30 to +90 (VL to VF)

Question 26

[ECG 1st principles]: What angles define left axis deviation

Answer 26

-30 to -90

Question 27

[ECG 1st principles]: what angles define Right axis deviation

Answer 27

+90 to -90 (180degrees)

Question 28

[ECG 1st principles]: broadly speaking what are R and L axis deviation a result of

Answer 28

R and L hypertrophy (Right may = PE Left may = conduction defect)

Question 29

[ECG 1st principles]: in what direction does the septum depolarise

Answer 29

from left to right

Question 30

[ECG 1st principles]: which ventricle exerts more influence on the ECG and why

Answer 30

Left - more mass.

Question 31

[ECG 1st principles]: what deflection would septal depolarisation display in leads V1/V2

Answer 31

upwards ('R' wave)

Question 32

[ECG 1st principles]: what deflection would septal depolarisation show in leads V5/V6

Answer 32

downwards ('Q' wave)

Question 33

[ECG 1st principles]: In a right ventricular lead would main ventricular depolarisation cause a positive or negative deflection

Answer 33

S wave - negative because the larger muscle mass of left ventricle outweighing the positive which would be seen from right ventricular depolarisation

Question 34

[ECG 1st principles]: [ECG 1st principles]: In a left ventricular lead would main ventricular depolarisation cause a positive or negative deflection

Answer 34

R wave - upward deflection as the main mass of the l ventricle is depolarising towards V5/V6

Question 35

[ECG 1st principles]: what is the 'transition point'

Answer 35

Where the R and S waves are equal - indicating the position of the interventricular septum.

Question 36

[ECG 1st principles]: the interventricular septum is usually seen in which leads (2)

Answer 36

V3/V4

Question 37

[ECG 1st principles]: what condition may cause the interventricular septum to shift into leads V4/V5 (or even V5/V6)

Answer 37

Right ventricular hypertrophy

Question 38

[ECG 1st principles]: A rhythm strip is usually produced from which lead (usually)

Answer 38

II

Question 39

[ECG 1st principles]: where would you find the rhythm strip on a full ECG print?

Answer 39

The bottom strip.

Question 40

[ECG 1st principles]: Whats may cause the ECG record line to look thickened

Answer 40

electrical interference - multiple very high frequency spikes . (electric lights/bed motors or mattresses)

Question 41

[ECG 1st principles]: incorrectly calibrated ECGs will produce very large QRS complexes which can be confused with left ventricular hypertrophy, or very small (pericardial effusion). Where would you look to see the calibration signal?

Answer 41

At the beginning of the trace. 1mV = 1cm

Question 42

[ECG 1st principles]: what is the normal paper run speed?

Answer 42

25 mm/s

Question 43

[ECG 1st principles]: skeletal muscle contraction can confuse the ECG. What should you ask the patient to do

Answer 43

Calm/relax/look out for parkinsons/tremor/shake

Question 44

[ECG 1st principles]: what might be seen in a patient who is not relaxed? and in one shivering?

Answer 44

spiky baseline especially in the limb leads Shivering = even more pronounced spikes

Question 45

[ECG 1st principles]: when reporting an ECG there are 5 sections. What are these?

Answer 45

1. Rhythm (normal rate = 50/min 2. Conduction intervals (normal/abnormal PR interval - 180ms &QRS duration - 120ms) 3. Cardiac axis 4. QRS description 5. ST and T wave description.

Question 46

[ECG 1st principles]: can you get right axis deviation in a normal tall individual

Answer 46

yes