Brainscape's Knowledge GenomeTM

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


See full index

ESA 2- Cardiovascular System > Common ECG Abnormalities > Flashcards

Common ECG Abnormalities Flashcards

1
Q

Viewing from lead II, what does atrial depolarisation produce?

A

A small upwards deflection

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

Why is atrial depolarisation a small deflection?

A

Because there is only a small amount of muscle

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

What is the deflection from atrial depolarisation upwards (viewing from lead II)?

A

Because its moving towards the electrode

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

What is deflection caused by atrial depolarisation called?

A

The P wave

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

What does presence of the P wave show?

A

Atrial activity, at that the activity starts at the SAN

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

What is conduction from the atrium to ventricle via?

A

The AV node and bundle of His

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

How quick is conduction from atrium to ventricle?

A

Slow

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

Why is conduction from atrium to ventricle slow?

A

To allow time for atrial contraction to fill ventricle

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

What does conduction from the atrium to the ventricle produce on the ECG?

A

A isoelectric (flat) segment

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

How does electrical activity spread in the interventricular septum?

A

Down the left and right branches of the bundle of His, faster down the left bundle

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

What is the result of depolarisation being faster down the left bundle?

A

The muscle in the interventricular septum depolarises from right to left

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

What does depolarisation down the interventricular septum produce in the ECG wave?

A

A small downwards deflection

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

Why does spread down the interventricular septum produce a small downwards deflection (viewing from lead II)?

A

Downwards because moving away

Small because not moving directly away

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

What is the downwards deflection caused by the spread in the interventricular septum called?

A

Q wave

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

What does spread through the ventricle cause in the ECG (viewing from lead II)?

A

A large upwards deflection

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

Why does spread through the ventricle cause a large upwards deflection (viewing from lead II)?

A

Upwards because moving towards

Large because lots of muscle, and moving directly towards the lead

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

What is the large upwards deflection caused by spread through the ventricle called?

A

The R peak

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

What happens at the end of depolarisation?

A

Depolarisation spreads towards the base of the ventricles

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

What is produced in the ECG when depolarisation spreads upwards to the base of depolarisation (viewing from lead II)?

A

A small downwards deflection

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

Why is a small downwards deflection produced at the end of depolarisation (viewing from lead II)?

A

Downwards because moving way

Small because not moving directly away

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

What is the downwards deflection at the end of depolarisation called?

A

S wave

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

Where does ventricular repolarisation begin?

A

Epicardial surface

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

How does ventricular repolarisation?

A

In the opposite way to depolarisation

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

What does ventricular repolarisation produce in the ECG (viewing from lead II)?

A

Medium upwards deflection

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

Why does ventricular repolarisation cause an upwards deflection?

A

Because its moving away

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

What is the deflection caused by ventricular repolarisation called?

A

T wave

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

What is the first step in reading an ECG?

A

Assess rhythm

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

What do you need know to assess rhythm?

A

What it looks like in lead 2- don’t need to look at all 12 leads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What do you look at to assess rhythm?

A

The long rhythm strip

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What do all ECG machines run at?

A

25m/sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What do 5 large squares equal in time?

A

1 sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How do you calculate rate from ECG if rhythm is regular?

A

Dividing 300 by the same of small squares in the R-R interval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How do you calculate rhythm if its irregular?

A

Count number of QRS complexes in 6 seconds, then times by 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the normal PR interval?

A

0.12-2 seconds (3-5 small boxes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is meant by the QRS interval?

A

The width of the QRS complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the normal QRS interval?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the normal QT interval?

A

It varies with heart rate, so must correct calculation for heart rate
Upper limit of corrected QT interval for males is 0.45, and for females 0.47s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are the steps of assessing rhythm?

A

Assess P wave
Calculate PR interval
Check relationship between P waves and QRS complexes
Assess QRS complexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What should be looked for when assessing P waves?

A

Is it absent or abnormal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Why do you need to calculate PR interval?

A

It estimates conduction in AV node and bundle of His

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What should you be looking for when assessing relationship between P waves and QRS complexes?

A

Is every P wave followed by QRS, and vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What do narrow QRS complexes indicate?

A

That rhythm starts in the atria/AVN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What do broad QRS complexes indicate?

A

Rhythm is originating in ventricles, or there is bundle branch block

44
Q

Where is depolarisation initiated in sinus rhythm?

A

Depolarisation

45
Q

What will be seen on the ECG in sinus rhythm?

A 
Rate 60-100bpm
 P upright in leads I and II
 PR interval normal
 Every P wave followed by QRS
 Every QRS preceded by P wave
 Normal QRS width
46
Q

What is sinus rhythm with rate

A

Sinus bradycardia

47
Q

What is sinus rhythm with rate >100/min?

A

Sinus tachycardia

48
Q

What happens in atrial fibrillation?

A

The base of the atrium begins to act as the pacemaker, so different bits of the atrium depolarise at different times

49
Q

What will be seen in the ECG of atrial fibrillation?

A

No P wave

QRS complexes irregularly irregular, and

50
Q

What does the PR interval show?

A

The time taken for conduction of impulse to ventricles

51
Q

How is the PR interval calculated?

A

Time from start of P wave to start of QRS complex

52
Q

What happens in first degree heart block?

A

Slow conduction in AV node and His bundle

53
Q

What will be seen in the ECG of someone with first degree heart block?

A

P wave normal
PR interval prolonged to >5 small squares
QRS normal

54
Q

What are the types of second degree heart block?

A

Type 1 second degree HB, aka. Mobitz type 1 HB, Wenkebach phenomenon
Type 2 second degree HB

55
Q

What happens in type 1 second degree HB?

A

Progressive lengthening of PR interval, until one 1 is not conducted, allowing time for the AVN to recover and the cycle begins again

56
Q

What happens in type 2 second degree HB?

A

PR interval normal, but theres a sudden lack of conduction of beat, and so a dropped QRS (P wave, but no QRS)

57
Q

What is the problem with type 2 second degree HB?

A

High risk of progression to complete heart block

58
Q

What does type 2 second degree HB require?

A

Insertion of pacemaker

59
Q

What happens in third degree heart block?

A

P waves at normal rate, but not conducted to the ventricle, and so the ventricular pacemaker takes over, producing a ventricular escape rhythm

60
Q

What is seen in the ECG of someone with third degree heart block?

A

Rate very slow, 30-40bpm

Usually wide QRS complexes

61
Q

What is the problem with third degree HB?

A

HR slow to maintain BP and perfusion

62
Q

What does third degree HB require?

A

Urgent pacemaker insertion

63
Q

What are ectopic beats?

A

Premature contractions

64
Q

What are ectopic foci?

A

Abnormal pacemaker sites within the heart muscle

65
Q

What do ectopic foci display?

A

Automaticity

66
Q

What normally happens to ectopic foci?

A

Thet are suppressed by the higher rate of the SA node in overdrive suppression

67
Q

Where can ectopic foci occur?

A

Within atria (atrial ectopics) or ventricles (ventricular ectopics)

68
Q

What happens in ventricular ectopic beats?

A

Ectopic focus is in ventricle

Depolarisation spreads form muscle, but not via Purkinje system

69
Q

What is the result of depolarisation not spreading through the Purkinje system with ectopic beats?

A

There is a much slower depolarisation

70
Q

What is seen in an ECG of ectopic beats?

A

Wide QRS complex

Different shape to usual QRS

71
Q

What is ventricular tachycardia?

A

A run of 3 or more consecutive ventricular ectopics

72
Q

What is ventricular fibrillation?

A

Abnormal, chaotic, fast ventricular depolarisation producing no coordinated contraction, and therefore a very rapid, irregular heart rhythm

73
Q

What causes ventricular fibrillation?

A

Impulses arising in numerous ectopic sites in ventricular muscle

74
Q

How do atrial and ventricular fibrillation differ?

A

In atrial fibrillation, atrial depolarisation is chaotic, whereas in ventricular fibrillation, ventricular depolarisation is chaotic

75
Q

What happens to the ventricles in atrial fibrillation?

A

Impulses are conducted irregularly to the ventricles, so there is ventricular depolarisation and contraction

76
Q

What happens to the ventricles in ventricular fibrillation?

A

There is no coordinated ventricular contraction

77
Q

What happens to the pulse and heart rate in atrial fibrillation?

A

The pulse and heart rate are irregularly irregular

78
Q

What happens to the pulse and heart rate in ventricular fibrillation?

A

There is none

79
Q

How do the limb leads view the heart?

A

In vertical plane

80
Q

What leads view the inferior surface of the RV and LV?

A

II, III and aVF

81
Q

What leads view the free wall of the LV?

A

I and aLV

82
Q

What does the aVR lead view?

A

Atrial and ventricular cavities

83
Q

How do the chest leads view the heart?

A

In horizontal plane

84
Q

What leads face the right ventricle?

A

V1 and V2

85
Q

What leads face the interventricular septum?

A

V3 and V4

86
Q

What leads face the left ventricle?

A

V5 and V6

87
Q

What causes ischaemic heart disease?

A

Reduced myocardial perfusion

88
Q

What can cause reduced myocardial perfusion?

A

Partial occlusion of coronary arteries

Acute occlusion by thrombus

89
Q

What does partial occlusion of coronary arteries lead to?

A

Poor myocardial perfusion, particularly on exercise, leading to pain on exercise

90
Q

What is shown in the ECG of someone with partial occlusion of coronary artery?

A

ECG often normal at rest, but changes seen in exercise

91
Q

What can sub-endocardial ischaemia cause?

A

ST depression facing the affected area

92
Q

What does acute occlusion by thrombus cause?

A

Death of part of the myocardium- a myocardial infarction

93
Q

What are the ECG features of a fully evolved myocardial infarction?

A

Abnormal Q waves
ST segment elevation
T wave inversion

94
Q

What causes abnormal Q waves in myocardial infarctions?

A

Myocardial necrosis

95
Q

What causes ST segment elevation in myocardial infarctions?

A

Subepicardial injury

96
Q

Where do ECG changes occur when there is a myocardial infarction?

A

ECG leads facing the infarcted area

97
Q

What are pathological Q waves?

A

Those that are more that 0.04s (1 small square) wide, and more than 2mm deep

98
Q

When are pathological Q waves present?

A

In full thickness myocardial infarction, and remain after other changes resolve

99
Q

What is the cardiac axis?

A

The average (overall) direction of the spread of ventricular depolarisation

100
Q

In what direction is the cardiac axis normally?

A

Downwards and to the left- between -30º and +90º

101
Q

What is considered to be a right axis?

A

More than +90º

102
Q

What is right axis deviation associated with?

A

Right ventricular hypertrophy

103
Q

What happens to the QRS complex in right axis deviation?

A

Lead I is inverted

Lead III is upright

104
Q

What is considered to be left axis?

A

Less than -30º

105
Q

What is left axis deviation associated with?

A

Left ventricular hypertrophy

Conduction blocks in anterior part of left bundle

106
Q

What happens to the QRS complex in left axis deviation?

A

Lead I is upright

Lead III is inverted

107
Q

What should be reported on when reporting an ECG?

A 
Rate
 Rhythm
 Conduction intervals- PR, QRS, QT
 Axis
 P wave- LA or RA enlargement
 Description of QRS complex
 ST segment
 T wave

ESA 2- Cardiovascular System (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions