ECG Lecture

Question 1

What is the double membrane sac that surrounds the heart?

Answer 1

PeriCardium

Question 2

Name the 3 parts of the pericardium

Answer 2

1- Fibrous
2- Serous - Parietal & visceral
3- Pericardial cavity

Question 3

What are the 3 layers of the heart

Answer 3

1- Endo Cardium
2- Myo Cardium
3- Epi Cardium

Question 4

Flow of the blood through the heart

Answer 4

1- Right Atrium
2- Tricuspid valve
3- Right Ventricle
4- Pulmonary Valve
5- Pulmonary artery
6- Pulmonary vein
7- Left Atrium
8 - Mittral (bicuspid) valve
9- Left Ventricle
10 - Aortic Valve

Question 5

2 types of cardiac muscles

Answer 5

1- Cardiomyocytes

2- Cardiac pacemaker cells

Question 6

Electrical conduction of the heart

Answer 6

1- SA Node
2- Bachmann's bundle
3- AV Node
4- Bundle of His
5- Right & left Bundle Branch
6 - Purkinje Fibres

Question 7

Intrinsic heart rate of SA node

Answer 7

60-100

Question 8

Intrinsic rate of AV node

Answer 8

40-60

Question 9

Intrinsic rate of Purkinje Fibres

Answer 9

30-40

Question 10

What deflection will occur with current heading towards an electrode?

Answer 10

Positive/upwards

Question 11

What deflection will occur with current heading away from an electrode?

Answer 11

Negative/downwards

Question 12

Location of limb leads

Answer 12

AVr- Right wrist
AVl - Left Wrist
AVf - Left ankle
Neutral - Right ankle

Question 13

Lead 1 direction & description

Answer 13

Towards AVL creating a second high lateral lead

Question 14

Lead II Direction and description

Answer 14

Towards AVf form Avr creating a 2nd inferior lead

Question 15

Lead III direction and description

Answer 15

Towards AVF from AVl creating a 3rd inferior lead

Question 16

What is the Cardiac Axis

Answer 16

Major direction of the overall electrical activity of the heart

Question 17

What would show a normal cardiac axis

Answer 17

positive on leads I and AVF

Question 18

What would show a LAD cardiac axis

Answer 18

positive lead I but negative on AVf

Question 19

What would show RAD

Answer 19

Negative lead I but positive on AVf

Question 20

What would show Extreme Axis Deviation

Answer 20

Negative both

Question 21

What does V1 and V2 look at

Answer 21

Right ventricle

Question 22

What does V3 and V4 look at

Answer 22

Septum and the anterior wall of the left ventricle

Question 23

What does V5 and V6 look at

Answer 23

Anterior and lateral walls of the left ventricle

Question 24

What does the P wave represent

Answer 24

Atrial depolarisation

Question 25

What does the Q wave represent

Answer 25

Septal depolarisation

Question 26

What does the R wave represent

Answer 26

Ventricular Depolarisation

Question 27

What does the S wave represent

Answer 27

depolarisation of purkinje fibres

Question 28

What does the t wave represent

Answer 28

Ventricular repolarisation

Question 29

normal PR interval

Answer 29

0.12-0.2s (3-5 squares)

Question 30

Normal QRS interval

Answer 30

<0.06-0.1s (1.5-2.5 squares)

Question 31

Normal QT interval

Answer 31

Rate dependent so corrected by machine. QTc 0.36-0.44s

Question 32

ECG paper speed

Answer 32

25mm/s

Question 33

Time of horizontal displacement

Answer 33

1 small = 0.04s

1 Large = 0.2s

Question 34

Vertical Displacement

Answer 34

1 small = 0.1mV

1 large = 1mV

Question 35

Subject Preparation

Answer 35

1- All clients to be offered a chaperone
2- Explain the procedure and gain full informed and written consent for EECG.
3- Explain that you are non-diagnostic
4- Disrobe from waist up (bra kept on)
5- If hairy chest, must be shaved with consent
6- if electrodes don’t stick use piece of abrasive paper to clear skin

Question 36

Poor skin contact: what and what does is cause

Answer 36

1- Chest hair, Wet skin, dry/old electrodes

2- Wandering baseline

Question 37

Movement Artefact

Answer 37

small high frequent waves

Question 38

Electrical Artefact

Answer 38

Dense waves