ECG Flashcards

1
Q

What does P wave represent?

A

Atrial depolarisation

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2
Q

What does PR interval represent?

A

Time for electrical activity to move between the atria and the ventricles

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3
Q

When does PR interval begin and end?

A

Begins at the start of the P wave and ends at the beginning of the Q wave

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4
Q

What does QRS complex represent?

A

Depolarisation of the ventricles

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5
Q

When does ST segment begin and end?

A

Starts at the end of the S wave and ends at the beginning of the T wave

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6
Q

What does ST segment represent?

A

Time between depolarisation and repolarisation of the ventricles (i.e. ventricular contraction)

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7
Q

What does T wave represent?

A

Ventricular repolarisation

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8
Q

When does RR interval begin and end?

A

Begins at the peak of one R wave and ends at the peak of the next R wave

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9
Q

What does RR interval represent?

A

Time between two QRS complexes

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10
Q

When does QT interval begin and end?

A

Begins at the start of the QRS complex and finishes at the end of the T wave

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11
Q

What does QT interval represent?

A

Time taken for the ventricles to depolarise and then repolarise

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12
Q

How long does each small square on ECG paper represent

A

0.04 seconds

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13
Q

How long does each large square on ECG paper represent

A

0.2 seconds

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14
Q

How long does 5 large square on ECG paper represent

A

1 second

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15
Q

How long does 300 large squares on ECG paper represent

A

1 minute

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16
Q

Placement of V1 chest electrode…

A

4th intercostal space at the right sternal edge

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17
Q

Placement of V2 chest electrode…

A

4th intercostal space at the left sternal edge

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18
Q

Placement of V3 chest electrode…

A

Midway between the V2 and V4 electrodes

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19
Q

Placement of V4 chest electrode…

A

5th intercostal space in the midclavicular line

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20
Q

Placement of V5 chest electrode…

A

Left anterior axillary line at the same horizontal level as V4

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21
Q

Placement of V6 chest electrode…

A

Left mid-axillary line at the same horizontal level as V4 and V5

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22
Q

Placement of red RA electrode….

A

Ulnar styloid process of the right arm

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23
Q

Placement of yellow LA electrode….

A

Ulnar styloid process of the left arm

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24
Q

Placement of green LL electrode….

A

Medial or lateral malleolus of the left leg

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25
Q

Placement of black RL electrode….

A

Medial or lateral malleolus of the right leg

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26
Q

Which chest leads have septal view of the heart?

A

V1 and V2

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27
Q

Which chest leads have anterior view of the heart?

A

V3 and V4

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28
Q

Which chest leads have lateral view of the heart?

A

V5, V6, Lead I, aVR, aVL

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29
Q

Which chest leads have inferior view of the heart?

A

Lead II, Lead III, aVF

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30
Q

When the electrical activity within the heart travels towards a lead, you get a…..

A

Positive deflection

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31
Q

When the electrical activity within the heart travels away from a lead, you get a……

A

Negative deflection

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32
Q

If the R wave is greater than the S wave, it suggests depolarisation is moving _________ lead

A

Towards the

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33
Q

If the S wave is greater than the R wave,it suggests depolarisation is moving ________ that lead

A

Away from

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34
Q

If the R and S waves are of equal size, it means depolarisation is travelling at exactly __________

A

90° to that lead

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35
Q

In healthy individuals, the electrical activity of the heart begins at the ________ then spreads to the ________. It then spreads down the __________ and _________ to cause ventricular contraction

A

Sinoatrial node (SA)
Atrioventricular (AV) node
Bundle of His
Purkinje fibres

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36
Q

In healthy individuals, you would expect the cardiac axis to lie between ________, axis spreads from _________

A

-30°and +90º
11 o’clock to 5 o’clock

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37
Q

The overall direction of electrical activity in a healthy individual is towards leads _________

A

I, II and III

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38
Q

In healthy individuals see positive deflection in leads __________ with __________ showing the most positive deflection as it is the most closely aligned to the overall direction of electrical spread

A

Leads I, II, II

Lead II

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39
Q

In healthy individuals see the most negative deflection in _______ this is because _____ produces viewpoint of the heart from the opposite direction

A

aVR

40
Q

Right axis deviation (RAD) involves the direction of depolarisation being ______, cardiac axis ______

A

Distorted to the right
Between +90º and +180º

41
Q

Most common cause of RAD is…..

A

Chronic pulmonary disease
Right ventricular hypertrophy
Left posterior fascicular block
Acute pulmonary embolism
Lateral myocardial infarction

42
Q

Right axis deviation causes the deflection in _______ to become negative and the deflection in ___________ to be more positive

A

Lead I
Lead aVF/III

43
Q

Light axis deviation (LAD) involves the direction of depolarisation being ______, cardiac axis ______

A

Distorted to the left
Between -30° and -90°

44
Q

Left axis deviation causes deflection of _______ becoming positive and defelection of _______ becoming negative

A

Lead I
Lead aVF

45
Q

Left axis deviation causes deflection of _______ becoming negative (this is only considered significant if the deflection of _______ also becomes negative)

A

Lead III
Lead II

46
Q

_______________ usually cause left axis deviation

A

Conduction abnormalities

47
Q

Causes of LAD

A

Left anterior fascicular block
Left bundle branch block
Left ventricular hypertrophy
Inferior myocardial infarction

48
Q

Normal adult heart rate

A

60-100 bpm

49
Q

Tachycardia heart rate

A

> 100 bpm

50
Q

Bradycardia heart rate

A

< 60 bpm

51
Q

If regular heart rhythm, heart rate can be calculated using the following method….

A

300 / Number of large squares present within one R-R interval

52
Q

If irregular heart rhythm, heart rate can be calculated using the following method….

A

Count the number of complexes on the rhythm strip (each rhythm strip is typically 10 seconds long)

Multiply the number of complexes by 6 (giving you the average number of complexes in 1 minute)

53
Q

Absent P wave on ECG suggest

A

Irregular rhythm

54
Q

How long should PR interval be

A

120-200 ms
3-5 small squares

55
Q

How long should QRS complex be

A

70-110 ms

56
Q

A prolonged PR interval suggests the presence of ___________

A

Atrioventricular delay (AV block)

57
Q

Typical ECG findings in first-degree heart block

A

Fixed prolonged PR interval (>200 ms)

58
Q

Typical ECG findings in second-degree (Mobitz Type I) heart block

A

Progressive prolongation of the PR interval until eventually the atrial impulse is not conducted and the QRS complex is dropped

AV nodal conduction resumes with the next beat, and the sequence of progressive PR interval prolongation and the eventual dropping of a QRS complex repeats itself

59
Q

Typical ECG findings in second-degree (Mobitz Type II) heart block

A

Consistent PR interval duration with intermittently dropped QRS complexes due to a failure of conduction

The intermittent dropping of the QRS complexes typically follows a repeating cycle of every 3rd (3:1 block) or 4th (4:1 block) P wave

60
Q

Third-degree (complete) AV block occurs when there is _______________________ due to a complete failure of conduction

A

No electrical communication between the atria and ventricles

61
Q

Typical ECG findings in third-degree (complete) heart block

A

Presence of P waves and QRS complexes that have no association with each other, due to the atria and ventricles functioning independently

62
Q

Narrow-complex escape rhythms (QRS complexes of <0.12 seconds duration) originate _______________

A

Above the bifurcation of the bundle of His

63
Q

Broad-complex escape rhythms (QRS complexes >0.12 seconds duration) originate __________________

A

Below the bifurcation of the bundle of His

64
Q

Shortened PR interval indicates ______________ or __________

A

P wave originates closer to AV node

Atrial impulse getting to ventricle via accessory pathway

65
Q

Typical ECG finding if atrial impulse getting to ventricle via accessory pathway

A

Delta wave

66
Q

A pathological Q wave is _______ the size of the R wave that follows it or _____ in height and______ in width

A

> 25%
2mm
40ms

67
Q

ST-elevation is significant when it is _________________ or __________________

A

> 1 mm (1 small square) in 2 or more contiguous limb leads

> 2mm in 2 or more chest leads

68
Q

ST elevation most commonly caused by….

A

Acute full-thickness myocardial infarction

69
Q

ST depression ≥ 0.5 mm in ≥ 2 contiguous leads indicates……..

A

Myocardial ischaemia

70
Q

T waves are considered tall if they are ______ in the limb leads and ________ in the chest lead

A

> 5mm
10mm

71
Q

Tall T waves can be associated with……

A

Hyperkalaemia
Hyperacute STEMI

72
Q

Inverted T waves normal in….

A

V1 and lead III

73
Q

Inverted T wave in leads besides V1 and lead III can indicate

A

Ischaemia

Bundle branch blocks (V4-6 in LBBB and V1-V3 in RBBB)

Pulmonary embolism

Left ventricular hypertrophy (in the lateral leads)

Hypertrophic cardiomyopathy (widespread)

General illness

74
Q

Biphasic T waves have two peaks and can indicate ____________ and ____________

A

Ischaemia
Hypokalaemia

75
Q

Flattened T waves are a non-specific sign that may represent _____________ or ___________

A

Ischaemia
Electrolyte imbalance

76
Q

U wave is a ___________ after the T wave best seen in ______ or ______

A

> 0.5mm deflection
V2 or V3

77
Q

The _______ the bradycardia the _______ the U wave

A

Slower
Larger

78
Q

Classically, U waves seen in…

A

Electrolyte imbalances
Hypothermia
Secondary to antiarrhythmic therapy → e.g digoxin, procainamide or amiodarone

79
Q

Changes in leads with inferior view (II ,III, aVF) of the heart indicate ___________ occlusion

A

Right coronary artery

80
Q

Changes in leads with anterior view (V3, V4) of the heart indicate ___________ occlusion

A

Distal Left Anterior Descending Artery

81
Q

Changes in leads with septal view (V1, V2) of the heart indicate ___________ occlusion

A

Left Anterior Descending Artery

82
Q

Changes in leads with lateral view (I, aVL, V5, V6) of the heart indicate ___________ occlusion

A

Circumflex artery

83
Q

Changes in leads I, aVL, V2-V6 of the heart indicate ___________ occlusion

A

Proximal Left Coronary Artery

84
Q

Tall R in lead V1 indicate ___________ occlusion

A

Right Coronary Artery

85
Q

What does this image indicate?

A

ST elevation

86
Q

What does this image indicate?

A

ST depression

87
Q

Typical ECG finding in Brugada syndrome

A

Classic ST elevation with partial right bundle branch block pattern in V1/V2

Persistent coved shape ST elevation with T wave inversion in leads V1-V2

88
Q

Downsloping ST segment is typical with…

A

Therapeutic doses of digoxin

89
Q

Typical ECG finding of RBBB

A

V1: RSR’ pattern in V1, with (appropriate) discordant T wave changes

V6: Widened, slurred S wave in V6

90
Q

Typical ECG finding of LBBB

A

V1: Dominant S wave
V6: broad, notched (‘M’-shaped) R wave

91
Q

Typical ECG finding of hypokalaemia

A

Down slopping ST segment (widespread) in association with T wave flattening or inversion and U wave

92
Q

Typical ECG finding of hyperkalaemia

A

Peaked T wave
Prolonged QT
Wide QRS complex
P wave flattening

93
Q

What does this ECG show and how to treat?

A

Ventricular Tachycardia
Treat with emergency DC Cardioversion

94
Q

What does this ECG show?

A

Atrial Flutter

95
Q

What does this ECG show?

A

Ventricular fibrillation

96
Q

What does this ECG show?

A

Ventricular Flutter