Brainscape's Knowledge GenomeTM

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


See full index

Cardiovascular System > ECGs > Flashcards

ECGs Flashcards

1
Q

Where is the SA node located?

A

Top right hand corner of right atrium

near junction of SVC and right atrium

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

Why is the SA node specialised?

A

Myocytes do not contract
They spontaneously depolarise
to generate action potentials

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

What is the SA node known as?

A

Pacemaker of heart

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

Why is the SA node the pacemaker of the heart?

A

Beause it spontaneously depolarises faster than other parts of the electrical conducting system
So it sets the rhythm of the heart beat

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

What is it called when the SA node sets the rhythm of the heart beat?

A

Sinus rhythm

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

What happens after the SA node generates an action potential?

A

Wave of depolarisation spreads across internodal pathways and atrial myocytes, downwards and to left

Depolarised atrial myocytes contract

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

Where is the AV node located?

A

Interatrial septum

Above the tricuspid valve

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

What happens during depolarisation of the atrial myocytes and their contraction?

A

Action potential is held up at AV node

AV node delay

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

What is the purpose of AV node delay?

A

To allow time for all the atria to depolarise and contract

Emptying the atria, filling the ventricles

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

Wher doere does the AV node conduct the action potential to?

A

Down the bundle of His

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

Where is the bundle of His located?

A

Beginning of the interventricular septum

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

What is the only electrical conducting pathway between the atria and ventricles?

A

The bundle of His

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

Why is the bundle of His the only electrical conducting pathway between the atria and ventricles?

A

Because of fibrous rings between the atria and ventricles

non-conductive tissue

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

What does the bundle of His divide into?

A

Right bundle branch

Left bundle branch

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

Where do the right and left bundle branches lie?

A

Interventricular septum

sub-endocardially - just beneath endocardium

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

Where do the right and left bundle branches carry the action potential to?

A

Down the interventricular septum

to the apex

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

How does the interventricular septum depolarise?

A

From left to right

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

What carries the action potential from the apex of the heart?

A

Purkynje fibres

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

Where are the purkinje fibres located?

A

Walls of ventricles

sub-endocardially

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

Where do the purkinje fibres carry the action potential to?

A

Up the ventricular walls, to the base of the ventricles

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

How does the myocardium of the ventricles depolarise? Why?

A

From endocardium to epicardium

since bundle branches, His purkinje system lie sub-endocardially

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

What is an important feature of the His-purkinje system?

A

Carry action potentials extremely fast, almost simultaneously
So ventricular myocytes depolarise and contract in a synchronised way

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

What is the overall direction of depolarisation?

A

Towards the apex of the heart

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

What is the order of contraction in the heart?

A 
Atrial myocytes
Septum - left to right
Apex
Walls of ventricles - endocardium to epicardium
Base of ventricles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the order by which cardiomyocytes repolarise?

A

The opposite to the order by which they depolarised

Base of ventricles
Walls of ventricles - epicardium to endocardium
Apex
Septum - right to left

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

What does an ECG record?

A

Changes occurring on extracellular surface of cardiomyocytes during depolarisation and repolarisation

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

How is the ECG set up?

A

Electrodes placed on skin

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

If wave of depolarisation is moving towards a positive electrode, how does this show on an ECG?

A

Positive complex

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

If wave of depolarisation is moving away from a positive electrode, how does this show on an ECG?

A

Negative complex

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

If wave of repolarisation is moving towards a positive electrode, how does this show on an ECG?

A

Negative complex

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

If wave of repolarisation is moving away from positive electrode, how does this show on an ECG?

A

Positive complex

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

Why do deflections eventually return to the baseline?

A

Change takes over more than half of cardiomyocytes

Becoming more similar, change decreasing

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

What does a flat line on an ECG mean?

A

No significant electrical activity occurring in heart

No change on surface of caridomyocytes

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

If a wave of depolarisation is travelling directly towards a positive electrode, how does show on an ECG?

A

Tall positive complex

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

If a wave of depolarisation is travelling at an angle towards a positive electrode, how does this show on an ECG?

A

Shorter positive complex

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

If a wave of depolarisation is travelling perpendicularly towards a positive electrode, how does this show on an ECG?

A

Small biphasic complex - positive then negative

or no complex

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

How does depolarisation of the SA node show up on an ECG? Why?

A

Flat line, baseline

Insufficient electrical activity to be picked up by ECG

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

How does depolarisation of the atria show up on an ECG? Why?

A

Produces small positive complex

Because wave of depolarisation is moving towards positive electrode at apex, at an angle

Shows up because is large muscle mass depolarising

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

What is the ECG wave corresponding to atrial depolarisation?

A

P wave

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

How does the AV node delay show up on an ECG?

A

Flat line, baseline

called segment 1b

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

How does depolarisation of the His-purkinje system show up on an ECG?

A

Flat line, baseline

still segment 1b

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

How dows depolarisation of the interventricular septum show on an ECG? Why?

A

Short negative complex

Because moving away from positive electrode at apex, at an angle

Shows up because is large muscle mass depolarising

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

What does depolarisation of the interventricular septum correspond to on an ECG?

A

Q wave

44
Q

How does depolarisation of the apex and ventricular wall show up on an ECG?

A

Tall positive complex

Because depolarisation moving directly towards positive electrode at apex
Also because large muscle mass is depolarising

45
Q

Which wave on an ECG corresponds to depolarisation of the apex and ventricular walls?

A

R wave

46
Q

In LV hypertrophy, how is the R wave different? Why?

A

Taller

due to larger muscle mass depolarising

47
Q

How does depolarisation of the base of the ventricles show up on an ECG?

A

Short negative complex

Because moving away from positive electrode at apex, but at an angle

48
Q

Which wave on an ECG corresponds to depolarisation of the base of the ventricles?

A

S wave

49
Q

How does ventricular repolarisation show up on an ECG?

A

Medium positive complex

Because repolarisation is moving away from positive electrode at apex
at an angle

50
Q

Which wave on an ECG corresponds to repolarisation of the ventricles?

A

T wave

51
Q

How many electrodes are placed on the skin in an ECG?

A

Ten

52
Q

What are the ten ECG electrodes divided into?

A

Four on the limbs

Six on the chest

53
Q

Where are each of the four limb electrodes placed?

A

Right arm - red
Left arm - yellow
Left leg - green
Right leg - black

54
Q

What is a lead?

A

Refers to view of the heart

55
Q

How many views do the four limb leads give?

A

Six

56
Q

What can the six limb lead views be divided into?

A

Unipolar leads

Bipolar leads

57
Q

What are the unipolar leads?

A

aVF
aVR
aVL

58
Q

What are the bipolar leads?

A

Lead 1
Lead 2
Lead 3

59
Q

What are the positive and negative poles with the unipolar limb leads?

A

Positive pole is one electrode, see from here

Negative pole is average of other two electrodes, ends up being heart

60
Q

What does avF look at?

A

Heart from left leg

its inferior surface

61
Q

What does avR look at?

A

Heart from right arm

62
Q

What does aVL look at?

A

Heart from left arm

its left lateral surface

63
Q

What are the degrees of aVF, aVL, aVR?

A 
aVF = 90degrees
aVR = -150degrees
avL = -30degrees
64
Q

What are the positive and negative poles with the bipolar limb leads?

A

Positive pole is one electrode

Negative pole is another electrode

65
Q

What are lead 1’s poositive and negative poles?

A

Left arm is positive pole

Right arm is negative pole

66
Q

What are lead 2’s positive and negative poles?

A

Left leg is positive pole

Right arm is negative pole

67
Q

What are lead 3’s positive and negative poles

A

Left leg is positive pole

Left arm is negative pole

68
Q

What does lead 1 look at?

A

Heart from left arm

its left lateral surface

69
Q

What do leads 2 and 3 look at?

A

Heart from left leg

its inferior surface

70
Q

What are the degrees of Leads 1, 2, and 3?

A

Lead 1 = 0 degrees
Lead 2 = 60 degrees
Lead 3 = 120 degrees

71
Q

The limb leads view the heart in what plane?

A

Coronal plane - vertical

72
Q

Where are each of the six chest electrodes placed?

A

V1 - 4th intercostal space, right sternal border
V2 - 4th intercostal space, left sternal border
V3 - between V2 and V4
V4 - 5th intercostal space, mid-clavicular line
V5 - between V4 and V6
V6 - 5th intercostal space, mix-axillary line

73
Q

What are V1 and V2 called?

A

The septal leads

74
Q

What do leads V1 and V2 look at?

A

Right ventricle and septum

75
Q

What are V3 and V4 called?

A

The anterior leads

76
Q

What do V3 and V4 look at?

A

Anterior wall of ventricles

apex

77
Q

What are V5 and V6 called?

A

Lateral leads

78
Q

What do V5 and V6 look at?

A

Left ventricle

79
Q

Why do each of the chest leads produce different ECGs?

A

At different angles to heart

Waves of depolarisation, repolarisation occur at different angles to each of them

80
Q

What plane do the chest leads view the heart in?

A

Transverse plane - horizontal

81
Q

If one of the chest leads is abnormal, what does this mean?

A

Damaged myocardium

in the area that the chest lead looks at

82
Q

What is the size of one small square on an ECG?

A

1mm x 1mm

83
Q

How long is one small square on an ECG?

A

0.04s

84
Q

What is the size of one large square on an ECG?

A

5mm x 5mm

85
Q

How long is one large square on an ECG?

A

0.2s

86
Q

What is the horizontal axis on an ECG?

A

Time (s)

87
Q

What is the vertical axis on an ECG?

A

Voltage (mV)

88
Q

How many squares is 1s on an ECG?

A

25 small squares

5 large squares

89
Q

How many squares is 1m on an ECG?

A

300 large squares

90
Q

How is a heart rate calculated if the rhythm is regular?

A

Count number of boxed between two R waves

Do 300/n

91
Q

What is a regular rhythm?

A

Same amount of time between cardiac cycles, one wave to next

92
Q

How is heart rate calculated if the rhythm is irregular?

A

Count number of R waves in 6 seconds, 30 large squares

Multiple by 10

93
Q

What is an irregular rhythm?

A

Different amounts of time between cardiac cycles, one wave to next

94
Q

What is the PR interval?

A

Beginning of P wave

To beginning of Q wave

95
Q

How long is a normal PR interval? How many squares?

A

0.12 - 0.20 seconds

3-5 small squares

96
Q

What is a QRS interval?

A

Beginning of Q wave

To end of S wave

97
Q

How long is a normal QRS interval? How many squares?

A

Less than 0.12 seconds

Less than 3 small squares

98
Q

What is the QT interval?

A

Beginning of Q wave

To end of T wave

99
Q

Does the QT interval vary with heart rate? Why?

A

Yes

Because time in diastole varies with heart rate

100
Q

How long is the normal QT interval? How many squares?

A

Males - 0.45s

Females - 0.47s

11-12 small squares

101
Q

What is sinus rhythm?

A

Depolarisation initiated by SA node

102
Q

What are the criteria of sinus rhythm?

A

Regular rhythm

Heart rate 60-100bpm

P waves

  • upright in leads 2 and 3
  • followed by QRS

Normal PR interval
Normal QRS interval

103
Q

What is sinus bradycardia?

A

Heart rate below 60bpm

104
Q

When is sinus bradycardia physiologically normal?

A

Sleeping

Athletes

105
Q

What is sinus tachycardia?

A

Heart rate above 100bpm

106
Q

When is sinus tachycardia physiologically normal?

A

Exercise

Cardiovascular System (22 decks)

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