Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

cardiovascular system > A First Look at the ECG > Flashcards

A First Look at the ECG Flashcards

1
Q

in what plane do standard limb leads look a events?

A

vertical (frontal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the 3 standard limb leads?

A

SLL I (left arm to right arm)

SLL II (left leg to right arm)

SLL III (left leg to left arm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the basic principles of standard limb leads?

A
  • fast events (depolarisation and repolarisation of action potential) are transmitted well
  • slow events (plateau of the action potential) are not transmitted well
  • a wave of approaching depolarisation causes an upward-going blip
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does each lead of the SLL record?

A

difference in potential between the two body parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what can the depolarisation wave be compared to?

A

wave of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what happens if a wave of depolarisation travels towards the left arm?

A

positive potential relative to the other node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happens if a wave of depolarisation travels away from the left arm?

A

negative potential compared to other node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what happens if a wave of repolarisation travels towards the left arm?

A

Negative potential compared to other node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what happens if a wave of repolarisation travels away from left arm?

A

positive potential compared to other node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does the P wave of an ECG represent?

A

atrial depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does the QRS complex of an ECG represent?

A

ventricular depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does the T wave of an ECG represent?

A

ventricular repolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the flat line between the P wave and Q on an ECG represent?

A

plateau of atrial repolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does the flat line between S and the T wave on an ECG represent?

A

plateau after ventricular depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does the plateau of atrial and ventricular repolarisation show a flat line on the ECG?

A

slow even so is not detected well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the PR interval?

A

time from atrial depolarisation to ventricular depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the time from atrial depolarisation and ventricular depolarisation called?

A

PR interval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the PR interval due to?

A

transmission through AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the time of the PR interval normally?

A

0.12 - 0.2s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the QRS interval?

A

time for the whole of the ventricle to depolarise

0.08s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the QT interval?

A

time spent while ventricles are depolarising

0.42s at 60bpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does the QT interval vary with?

A

heartrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what cannot be seen on the ECG?

A

atrial repolarisation

coincides with ventricular depolarisation which involves much more tissue depolarising faster so swamps any signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

why is the QRS complex so complicated?

A

different parts of the ventricle depolarising at different times in different directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

why is the T wave positive?

A

action potential is no longer in endocardial cells but in epicardial cells so the wave runs in the opposite direction to the wave of depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

in which SLL is the R wave biggest?

A

SLL II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

why is the R wave biggest in SLL II?

A

the main vector of depolarision is in line with the axis of recording from the left leg with respect to the right arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are the steps of the QRS complex?

A
  1. interventricular septum depolarises from left to right
  2. the bulk of ventricle depolarises from endocardial to epicardial surface
  3. upper part of the interventricular septum depolarises
29
Q

what other limbs leads can be used other than SLL?

A

augmented limb leads

30
Q

what do augmented limb leads give combined with standard limb leads?

A

3 additional perspectives on the events of the heart

31
Q

what are augmented limb leads?

A

recordings from one limb lead with respect to the 2 others combined

32
Q

when is the ECG negative?

A
  • when depolarisation is travelling away from the electrode
  • when repolarisation is travelling towards the electrode
33
Q

When is the ECG positive?

A
  • when depolarisation is travelling towards the electrode
  • when repolarisation is travelling away from the electrode
34
Q

what plane do precordial (chest) leads get information in?

A

horizontal (transverse) plane

35
Q

what leads get information in the horizontal (transverse) plane?

A

precordial (chest leads)

36
Q

how many electrodes are used in precordial (chest) leads?

A

6 (V1 to V6)

37
Q

how does the wave change from V1 to V6?

A

negative blips at V1 going to positive blip at V6, changing somewhere around V3 or V4

38
Q

which chest electrode has the greatest positive blip?

39
Q

which chest electrode has the greatest negative blip?

40
Q

how many perspectives does using all available leads allow?

A

6 angles in the coronal plane

6 angles in the transverse plane

41
Q

what is the advantage of looking at the heart from 12 perspectives?

A

changes in the spread of depolarisation will affect the ECG in a predictable manner

42
Q

what does I, II and III along the left show?

A

standard limb leads (SLL)

43
Q

what does aVR, aVL and aVF in the middle-left show?

A

augmented limb leads

44
Q

what does V1 to V6 at the right show?

A

precordial (chest) leads

45
Q

what does II at the bottom show?

A

rhythm strip

46
Q

what is the limb lead between between the right arm and the middle of SLL III called?

47
Q

what is the limb lead between the left arm and SLL II called?

48
Q

what is the limb lead between the left foot and SLL I called?

49
Q

hat is aVR between?

A

right arm and SLL III

50
Q

what is aVL between?

A

left arm and SLL II

51
Q

what is aVF between?

A

left leg and SLL I

52
Q

what is the rhythm strip?

A

continuous recording from SLL II

53
Q

what does the rhythm strip allow you to work out?

A

heart rate

54
Q

what speed does the ECG paper run at?

55
Q

how large is the calibrating pulse of the ECG?

A

0.2s (1 large square, 5mm)

56
Q

what does 1 large square on an ECG represent?

57
Q

how is the heart rate worked out from the rhythm strip?

A

measure the R-R interval and work out how many occur in 60s

or count the R waves in 30 larger squares (this is 6s) and multiple by 10

58
Q

what is the normal heart rate?

59
Q

what is considered to be bradycardia?

A

abnormally slow heart rate

<60bpm

60
Q

what is considered to be tachycardia?

A

abnormally fast heart rate

>100bpm

61
Q

What does the rhythm strip tell you?

A
  • is each QRS complex preceded by a P wave
  • is the PR interval too short or too long
  • is the QRS complex too wide
  • is the QT complex too long
62
Q

when is the PR interval too short?

63
Q

when is the PR interval too long?

64
Q

when is the QRS complex too wide?

65
Q

when is the QT complex too long?

A

>0.42s at 60bpm

66
Q

what is myocardial infarction?

A

blood flow decreases or stops to a part of the heart, causing damage to the heart muscle (heart attack)

67
Q

what are the 2 kinds of myocardial infarction?

A

STEMI: ST elevated myocardial infarction

NSTEMI

68
Q

which of STEMI and NSTEMI is worse?

cardiovascular system (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions