ECG basics Flashcards

1
Q

What three types of abnormalities are detected by an ECG?

A

Conduction abnormalities
Structural abnormalities
Perfusion abnormalities

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2
Q

What are the three main advantages of conducting an ECG?

A

Relatively cheap and easy to undertake

Reproducible between people and centres

Quick turnaround on results/report.

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3
Q

What is the definition of a vector?

A

A vector is a quantity that has both magnitude and direction

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4
Q

What does a downwards deflection represent in an ECG?

A

Downwards deflections are towards the anode

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5
Q

What does an upward deflection represent in an ECG?

A

Towards the cathode

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6
Q

What does the width of a a deflection denote in an ECG?

A

Denotes the duration of the event

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7
Q

What does the steepness of an ECG line denote?

A

The velocity of an action potential.

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8
Q

What does an isoelectric ECG line represent?

A

Represents no net change in voltage (vectors are perpendicular to the lead).

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9
Q

What does the p wave represent?

A

Electrical signal that stimulates contraction of the atria (atrial systole).
Autorythmic myocytes
Atrial depolarisation

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10
Q

What does the QRS complex represent?

A

The electrical signal that stimulates contraction of the ventricles (ventricular systole)

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11
Q

What does the T wave represent?

A

An electrical signal that signifies relaxation of the ventricles (ventricular repolarisation).

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12
Q

What does the PR segment represent?

A
AVN depolarisation (Isoelectric ECG)
There is slow signal transduction 

Protective

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13
Q

Describe the speed of electrical transmission through the Bundle of His?

A

Rapid conduction (insulated)

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14
Q

What type of depolarisation occurs within the bundle branches?

A

Septal depolarisation

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15
Q

What does the Q wave represents?

A

Septal depolarisation

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16
Q

Which fibres are responsible for ventricular depolarisation?

A

Purkinje fibres

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17
Q

Which ECG structure represents the fully depolarised ventricles?

A

ST-segment

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18
Q

Where does lead 1 go from and to?

A

From the right arm to the left arm

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19
Q

Where does lead 2 go to?

A

From the right arm to the left leg

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20
Q

Where does lead two go from and to?

A

From the right arm to the left leg

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21
Q

What is the direction of depolarisation (negative to positive) in lead 1?

A

Right to left (anode to cathode)

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22
Q

Where is V1 placed?

A

Right sternal border in the fourth intercostal space

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23
Q

Where is V2 placed?

A

Left sternal border in the fourth intercostal space.

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24
Q

Where is V3 placed?

A

Halfway between v2 and v4

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25
Q

Where is V4 placed?

A

In the 5th intercostal space at the mid clavicular line

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26
Q

Where is V5 placed?

A

Anterior axillary line at the level of V4

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27
Q

Where is V6 placed?

A

Mid axillary line at the level of V4.

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28
Q

Which electrode is placed in the fourth intercostal space at the mid clavicular line?

A

V4

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29
Q

Which coronary artery is associated with lead 1?

A

Left circumflex artery

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30
Q

Which coronary artery is associated with lead 2?

A

Right coronary artery

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31
Q

Which coronary artery is associated with lead 3?

A

Right coronary artery

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32
Q

Which coronary artery is associated with aVL?

A

Left circumflex artery

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33
Q

Which coronary artery is associated with AvF?

A

Right coronary artery

34
Q

Which coronary artery is associated with V1?

A

Left anterior descending artery

35
Q

Which coronary artery is associated with V2?

A

Left anterior descending artery

36
Q

Which artery is associated with V3?

A

Right coronary artery

37
Q

Which coronary artery is associated with V4?

A

Right coronary artery

38
Q

Which coronary artery is associated with v5?

A

left circumflex artery

39
Q

Which coronary artery is associated with v6?

A

Left circumflex artery

40
Q

Which ECG leads are associated with the lateral view of the heart?

A

Lead 1
aVL
V5 and V6

41
Q

Which coronary artery is associated with leads of the lateral view of the heart?

A

left circumflex artery

42
Q

Which ECG leads are associated with the anterior view of the heart?

A

V4

V3

43
Q

Which coronary artery is associated with the anterior view of the heart?

A

Right coronary artery

44
Q

Which ECG leads are associated with the inferior view of the heart?

A

Lead 2 and lead 3

AvF

45
Q

Which coronary artery is associated with the inferior view of the heart?

A

Right coronary artery

46
Q

Which ECG leads are associated with the septal view of the heart?

A

V1

V2

47
Q

Which coronary artery is associated with the septal view of the heart?

A

Left anterior descending artery

48
Q

Which leads are bipolar?

A

leads 1-3

49
Q

Which leads are located on the limb?

A

Lead 1-3
AVR
AVL
AVF

50
Q

Where is the cathode (+) located lead 1?

A

Left arm

51
Q

What are the pairs of perpendicular leads?

A

Lead 1 and AVF
Lead 2 and AVL
Lead 3 and AVR

52
Q

What is the first step of ECG reporting?

A

Check rate and rhythm (RR)

53
Q

What is the second step of ECG recording (after checking the rate)?

A

Check p-wave and PR interval

54
Q

What is the third stage of ECG recording (after checking the p-wave and pr interval)?

A

QRS duration

55
Q

What is step 4 of ECG reporting?

A

QRS axis (using perpendicular leads and net deflections)

56
Q

What is step 5 of ECG reporting?

A

Check ST segment

57
Q

What is step 6 of ECG reporting after checking the ST segment?

A

Check the QT interval

58
Q

what is the final step of ECG reporting?

A

T wave

59
Q

What is sinus rhythmn?

A

Each p-wave is followed by a QRS complex (1:1).

Rate is regular (R-R intervals even), and normal

60
Q

What is sinus bradycardia?

A

Each p wave is followed by a QRS complex (1:1).
Rate is regular (even R-R intervals) and slow (56bpm)

Can be caused by vagal stimulation or muscular heart (reduced heart rate to maintain same cardiac output).

61
Q

What is sinus tachycardia?

A

Each p-wave is followed by a QRS complex (1:1).

Rate is regular (even R-R intervals), and fast (107bpm)>

Often physiological

62
Q

What is sinus arrhytmia?

A

Each p-wave is followed by a QRS wave

Rate is irregular (variable R-R intervals), and normal (65-100bpm).

R-R intervals varies with breathing cycle

63
Q

Which type of cardiac abnormality is associated with a varying R-R interval with breathing cycles?

A

Sinus arrhythmia

64
Q

What is atrial fibrillation?

A

Oscillating baseline given the atria are contracting asynchronously.

The rhythm can be irregular and rate may be slow

Turbulent flow pattern increases clot risk

65
Q

Which type of cardiac abnormality is associated with an increased risk of embolism?

A

Atrial fibrillation due to inadequate atrial contraction and pumping of blood.

66
Q

What ECG pattern is commonly seen in atrial flutter?

A

There is a sawtooth pattern

67
Q

What is atrial flutter?

A

Regular saw-tooth pattern in baseline (leads II, III, and AVF).
Atrial to ventricular beats (2:1 ratio or 3:1 ratio
There are p waves without succeeding QRS complexes.

68
Q

What is the atria to ventricular beat ratio in individuals with atrial flutter?

A

2:1, 3:1 +

69
Q

What is first degree heart block?

A

The PR segment is inappropriately long, there is impaired conduction through the atrioventricular node to the ventricles.

prolongation is caused by slower AV conduction, there is a regular rhythm 1:1 ratio of p-waves to QRS complexes.

70
Q

Which form of heart block is associated with regular prolongation of the PR interval?

A

First degree heart block

71
Q

What is a mobitz-I heart block?

A

There is progressive prolongation of the PR interval until a beat is dropped.

Majority of p-waves are followed by QRS complex.

Regularly irregular, caused by diseased AV node.

I.E 75 75 40 75 75 40

72
Q

Which type of heart block is concerned with a progressive prolongation of the PR interval until there is a dropped beat?

A

Mobitz-I

73
Q

What type of rhythm is exhibited by a Mobitz-I heart block?

A

Regularly irregular

74
Q

What is a Mobitz-II heart block?

A

P-waves are regular, however only some are followed by QRS complex

There is NO PR prolongation.

Regularly irregular

75
Q

Which heart block is associated with no PR prolongation, however partially absent QRS complexes?

A

Mobitz-II.

76
Q

What is third degree heart block?

A

P-waves are regular, QRS are regular however there is no relationship
Truly non-sinus rhythmn, there is complete AV nodal failure.

77
Q

What is ventricular tachycardia?

A

P-waves are hidden, given that there is dissociated atrial rhythm.
Rate is regular and fast (100-200bpm).
Shockable rhythm

78
Q

What is ventricular fibrillation?

A

Heart is irregular and 250bpm and above

Unstable to generate cardiac output.

uncoordinated manner, the QRS complexes are irregular, thus there is no coordination of muscular contraction.

79
Q

What causes ST elevation?

A

Caused by infarction (tissue death caused by hypoperfusion).

80
Q

By what measurement is ST-elevation classified?

A

> 2mm above the isoelectric line

81
Q

What causes ST depression?

A

Myocardial infarction (coronary insufficiency).