Week 8- ECGs

Question 1

What are the 5 letters used to represent the different sections during one heartbeat on an ECG?

Answer 1

P, Q, R, S, T

Question 2

What does the P wave respresent?

Answer 2

Atrial depolarisation

Question 3

What does the QRS complex represent?

Answer 3

Ventricular depolarisation

Question 4

What does the T wave represent?

Answer 4

Ventricular repolarisation

Question 5

During what stage of the ECG does atrial repolarisation occur? Does it show up?

Answer 5

During the QRS complex, it doesnt show up as its to small and overpowered by ventricular depolarisation

Question 6

Which way does a normal P wave lie?

Answer 6

Upwards

Question 7

Which way does a normal Q wave lie?

Answer 7

Downwards

Question 8

Which way does a normal R wave lie?

Answer 8

Upwards

Question 9

Which way does a normal S wave lie?

Answer 9

Downwards

Question 10

Which way does a normal T wave lie?

Answer 10

Upwards

Question 11

How long does a normal P wave last?

Answer 11

0.1 secs

Question 12

How long does a normal PR interval last?

Answer 12

0.2 secs

Question 13

How long does a normal QRS complex last?

Answer 13

0.08 secs

Question 14

How long does a normal T wave last?

Answer 14

0.16 secs

Question 15

How long does a normal QT interval last?

Answer 15

0.4 secs

Question 16

What is a PR interval?

Answer 16

From the start of the P wave to before the start of the QRS complex

Question 17

What is a PR segment?

Answer 17

From the end of the P wave to before the start of the QRS complex

Question 18

What is a QT interval?

Answer 18

From the start of the Q wave to before the start of the T wave

Question 19

What is a ST interval?

Answer 19

From the start of the S wave to before the start of the T wave

Question 20

What is a ST segment?

Answer 20

From the end of an S wave to before the start of a T wave

Question 21

What is visible on an ECG when heart rate increases?

Answer 21

Shorter distance between 2 adjacent R waves mainly due to the TP interval shortening

Question 22

How are ECG signals measured?

Answer 22

Via pairs of electrodes, each pair is known as a lead

Question 23

How many leads can be measured in and ECG?

Answer 23

12

Question 24

How many electrodes are used during an ECG? Where are they found?

Answer 24

10- 6 on the chest and 4 on each limb (ankles and wrists)

Question 25

If a wave of depolarisation travels towards a positive electrode, what will show up on an ECG trace?

Answer 25

A positive wave

Question 26

If a wave of repolarisation travels towards a positive electrode, what will show up on an ECG trace?

Answer 26

A negative wave

Question 27

What does lead I connect?

Answer 27

Right arm (negative) to left arm (positive)

Question 28

What does lead II connect?

Answer 28

Right arm (negative) to left foot (positive)

Question 29

What does lead III connect

Answer 29

Left arm (negative) to left foot (positive)

Question 30

Which lead has the largest R wave and why?

Answer 30

Lead II as its most similar to the direction of ventricular depolarisation

Question 31

What is a standard limb lead?

Answer 31

A bipolar lead formed by connecting the electrocardiograph between 2 corners of the triangle (left arm, right arm and left leg)

Question 32

What are the 3 augmented limb leads?

Answer 32

aVf, aVr and aVl

Question 33

Which direction does aVr flow?

Answer 33

Bottom left of torso (negative) to right of torso (positive)

Question 34

Which direction does aVf flow?

Answer 34

From top middle of torso (negative) to left foot (positive)

Question 35

Which direction does aVl flow?

Answer 35

From bottom right of torso (negative) to left arm (positive)

Question 36

What is an augmented limb lead?

Answer 36

A composite lead formed by comparing a single positive electrode with a combination of the 2 other electrodes

Question 37

How is aVr calculated?

Answer 37

RA-(LA+LF)

Question 38

How is aVf calculated?

Answer 38

LF-(RA+LA)

Question 39

How is aVl calculated?

Answer 39

LA-(RA+LF)

Question 40

Are augmented limb leads bi or unipolar?

Answer 40

Unipolar

Question 41

What does 'augmented' in augmented limb lead represent?

Answer 41

ECG is greater in magnitude

Question 42

Which leads have a prominent R wave and a positive P and T wave?

Answer 42

I, III, aVf

Question 43

Which lead has a negative QRS complex, P and T wave and why?

Answer 43

aVr as all electrical activity flows away from the lead

Question 44

Where is V1 placed?

Answer 44

4th intercostal space, right side of the sternum

Question 45

Where is V2 placed?

Answer 45

4th intercostal space, left side of sternum

Question 46

Where is V3 placed?

Answer 46

5th rib, slightly lower than V2

Question 47

Where is V4 placed?

Answer 47

5th intercostal space mid clavicular line

Question 48

Where is V5 placed?

Answer 48

6th intercostal space anterior axillary line

Question 49

Where is V6 placed?

Answer 49

7th rib, anterior axillary line

Question 50

What part of the heart do leads V1 and V2 face?

Answer 50

Wall of the right ventricle

Question 51

What part of the heart do leads V3 and V4 face?

Answer 51

Intraventricular septum

Question 52

What part of the heart do leads V5 and V6 face?

Answer 52

The left ventricle ( at a distance)

Question 53

Why do leads viewing the heart from the right side have large negative S waves?

Answer 53

Left ventricular muscle mass of the heart is a lot higher than the right ventricular muscle mass

Question 54

Why may leads V3 and V4 have more prominent R and S waves?

Answer 54

They are close to the intraventricular septum

Question 55

What direction are P waves in leads V1 and V2?

Answer 55

Positive or bisphasic

Question 56

What direction are P waves in leads V4 and V6?

Answer 56

Always positive

Question 57

What direction are T waves in leads V1 and V2?

Answer 57

May be inverted

Question 58

What direction are T waves in leads V3 and V6?

Answer 58

Always positive

Question 59

In what plane do the limb lead view the heart?

Answer 59

Coronal

Question 60

In what plane do chest leads view the heart?

Answer 60

Transverse

Question 61

Are chest leads uni or bi polar?

Answer 61

Unipolar- they are single positive recording electrodes

Question 62

On a 12 lead ECG recording, what leads appear on the first row (go from left to right)?

Answer 62

aVR, V1 then V4

Question 63

On a 12 lead ECG recording, what leads appear on the second row (go from left to right)?

Answer 63

aVL, V2 then V5

Question 64

On a 12 lead ECG recording, what leads appear on the third row (go from left to right)?

Answer 64

aVF, V3 then V6