ECGs Revisited

Question 1

What part of ECG equipment is an electrode?

Answer 1

The thing that sticks onto your chest

Question 2

What part of ECG equipment are the cables/wires?

Answer 2

The wires connected to the electrodes

Question 3

What part of ECG equipment are the leads?

Answer 3

They are the views of the heart

Question 4

How are vectors represented?

Answer 4

By arrows

Question 5

In what direction will a charge travelling towards a negative electrode travel?

Answer 5

Down

Question 6

In what direction will a charge travelling towards a positive electrode travel?

Answer 6

Up

Question 7

What direction is the charge travelling if the line is isoelectric?

Answer 7

Perpendicular to both the anode and the cathode

Question 8

What does the steepness of the electrode denote?

Answer 8

The velocity of the action potential

Question 9

What does the width of the deflection denote?

Answer 9

The duration of the event

Question 10

How does the thickness of the muscle affect deflection?

Answer 10

Thinner muscle creates a smaller deflection

Question 11

How many limb leads and how many chest leads are there?

Answer 11

3 limb leads

6 chest leads

Question 12

What rule is used to remember where the leads go? How does it work?

Answer 12

Rule of Ls

Lead 1= one L= right arm to Left arm
Lead 2= two Ls= right arm to Left Leg
Lead 3= Left arm to Left Leg

Question 13

For the leads, what rule is used to work out which is the anode and which is the cathode? How does it work?

Answer 13

The rule of reading

In english we read from left to right and up to down
For each lead either go left to right or up to down and always start with the anode

Question 14

Where exactly is V1 placed?

Answer 14

4th intercostal space at right border of the sternum

Question 15

Where exactly is V2 placed?

Answer 15

4th intercostal space at the left border of the sternum

Question 16

Where exactly is V3 placed?

Answer 16

Between V2 and V4

Question 17

Where is V4 placed?

Answer 17

5th intercostal space at the mid clavicular line on the left

Question 18

Where exactly is V5 placed?

Answer 18

5th intercostal space at the anterior axillary line on the left (same level as V4)

Question 19

Where exactly is V6 placed?

Answer 19

5th intercostal space at the mid axillary line on the left (same level as V4 and V5)

Question 20

Which leads can be referred to as the chest leads?

Answer 20

V1, V2 and V3

Question 21

Which leads look at a lateral view of the heart and what vessel does this correspond to?

Answer 21

I, avL, V5 and V6

Left circumflex

Question 22

Which leads look at a septal view of the heart and what vessel does this correspond to?

Answer 22

V1 and V2

Left anterior descending

Question 23

Which leads look at an anterior view of the heart and what vessel does this correspond to?

Answer 23

V3 and V4

Left anterior descending

Question 24

Which leads look at a inferior view of the heart and what vessel does this correspond to?

Answer 24

II, III, avF

Right coronary artery

Question 25

What are the 3 main arteries that supply the heart? Include their abbreviations

Answer 25

Left circumflex (Lcx)
Left anterior descending (LAD)
Right coronary artery (RCA)

Question 26

What are the 2 different types of ECG leads?

Answer 26

Limb leads- they use the limbs (right/left arm and left foot)
Chest leads- V1-V6 placed on the chest

Question 27

Which leads are bipolar and which are unipolar?

Answer 27

Limb leads are bipolar, chest leads are unipolar

Question 28

What leads lie in the coronal plane?

Answer 28

Leads I, II, III, aVf, avL, avR

Question 29

What leads lie in the horizontal plane?

Answer 29

V1-V6

Question 30

Are V1-V6 anodes or cathodes?

Answer 30

Cathodes

Question 31

How many milliseconds are in a second?

Answer 31

1000

Question 32

What do you need in order to find the cardiac axis?

Answer 32

2 leads that are perpendicular to each other

Question 33

Explain how to cardiac axis is calculated?

Answer 33

The QRS vector for both perpendicular leads must be calculated. Then create a triangle, find the missing angle and subtract from 90 if it needs to be adjusted

Question 34

What leads are the augmented limb leads?

Answer 34

avR, avL, avF

Question 35

How are the vectors for the cardiac axis calculated?

Answer 35

Count how many squares up the QRS complex goes
Count how many squares down the QRS complex goes
Vector= squares up- squares down
It could be negative or positive