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1
Q

The duration of any wave may be determined by measuring along the (blank)

A

Horizontal axis

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2
Q

Limb leads

A

I, II, III, aVR, aVL, aVF

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3
Q

Chest leads

A

V1- V6

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4
Q

Lead I is horizontal and its left arm electrode is ______ while its right arm electrode is _____

A

Positive
Negative

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5
Q

Lead III: the left arm electrode is _____, while the left leg electrode is ________

A

Negative
Positive

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6
Q

What is Einthoven’s Triangle?

A

The bipolar limb lead configuration
(Right arm, left arm, left leg)

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7
Q

Lead II: the right arm electrode is _____ while the left leg electrode is_____

A

Negative
Positive

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8
Q

The aVF lead uses the left foot as _______

A

positive
aVF is a cross between leads II and III

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9
Q

where is the electrode positive in the following leads?
aVR:
aVL:
avF:

A

aVR: Right arm positive
aVL: Left arm positive
aVF: Foot positive (left foot

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10
Q

The flat plane of the limb leads is called the _______

A

Frontal plane

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11
Q

What are the lateral leads?

A

I, aVL, V5, V6

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12
Q

What are the inferior leads?

A

II, III, aVF

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13
Q

What are the anteroseptal leads?

A

V1-V4

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14
Q

What are the right ventricular leads?

A

aVR, V1, V2

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15
Q

What leads show the right ventricle?

A

V1, V2, V3, aVR

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16
Q

What leads show the interventricular septum?

A

V1, V2

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17
Q

What leads show the anterior of the heart?

A

V2, V3, V4

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18
Q

What leads show the lateral wall of the left ventricle?

A

V5, V6, I, aVL

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19
Q

What leads are associated with the RCA?

A

II, III, aVF

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20
Q

What leads are associated with the LAD?

A

V1-V4

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21
Q

What leads are associated with the LCX?

A

V5, V6, I, aVL

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22
Q

Define Automaticity foci

A

Potential pacemakers that are capable of pacing in emergency situations. They have the potential to pace at their inherent rate. They are in the atria, ventricles and AV junction

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23
Q

The rate of the automaticity foci within the atria

A

60-80

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24
Q

The rate of the automaticity foci within the AV Junction

A

40-60

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25
Q

The rate of the automaticity foci in the ventricles

A

20-40

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26
Q

Define overdrive suppression

A

Any automaticity center will overdrive-suppress all others that have a slower inherent pacemaking rate.

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27
Q

Define axis

A

Refers to the direction of depolarization as it passes through the heart

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28
Q

What is the axis of the heart?

A

The mean QRS vector when located by degrees in the frontal plane.

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29
Q

Sinus Rhythm

A
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30
Q

Sinus Bradycardia

A
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31
Q

Sinus Arrhythmia

A

an irregular rhythm that varies w respiration
-All p-waves are identical

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32
Q

Wandering pacemaker

A

P-waves change shape
Pacemaker location varies
Rate under 100 bpm

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33
Q

Multifocal atrial tachycardia

A

Same as Wandering pacemaker but with a rate above 100bpm

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34
Q

Atrial fibrillation

A

Irregular ventricular rhythm
-No p-waves
-Erratic atrial spikes from multiple atrial automaticity foci

Fibrillation: rate 350-450

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35
Q

Atrial Flutter

A

Flutter rate: 250-350
-Saw-toothed atrial complexes from a single rapid firing atrial focus
-Many flutter waves needed to produce a ventricular response

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36
Q

Atrial Escape Rhythm

A

60-80 bpm
A sick sinus node may cease pacing (sinus arrest) causing an automaticity focus to escape to assume pacemaker status

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37
Q

Junctional Escape Rhythm

A

40-60 bpm- idiojunctional

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38
Q

Ventricular Escape Rhythm

A

20-40 bpm - idioventricular

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39
Q

Ventricular Escape Beat

A
40
Q

Junctional Escape Beat

A
41
Q

Escape rhythm vs beat

A
42
Q

Premature Atrial beat

A

From an irritable automaticity focus

43
Q

Premature Junctional beat

A
44
Q

Premature ventricular contraction (PVC)

A

Ventricular focus produces a rapid (150-250 bpm) sequence of PVC-like wide ventricular complexes

45
Q

Paroxysmal atrial tachycardia (SVT)

A

AV-junction focus produces rapid sequence of QRS-T cycles at 150-250bpm
-QRS may be slightly widened

46
Q

Ventricular Tachycardia

A
47
Q

Torsades de Pointes

A
48
Q

Ventricular flutter

A

aka Torsades
Rapid, smooth waves from a single rapid-firing ventricular focus
-Usually short bursts leading to v.fib

49
Q

Ventricular fibrillation

A

Multiple ventricular foci rapidly discharging produce an erratic ventricular rhythm without identifiable waves
-Needs immediate tx

50
Q

Sinus Block

A

An unhealthy SA node misses one or more cycles

51
Q

First degree AV Block

A

Consistently prolonged PR interval greater than .2 seconds (one big box)

52
Q

2nd Degree Mobitz 1/Wenkebach

A

Some p-waves without QRS responses
-PR interval gradually lengthens with each cycle until the last P does not produce a QRS

53
Q

2nd degree Mobitz 2 AV block

A

Some P-waves don’t produce a QRS response

54
Q

Complete heart block (AV dissociation)

A
55
Q

Right Bundle Branch Block

A

Look at V1 for a double R, V6 for a swooping S wave

56
Q

Left Bundle Branch Block

A

Look at V1 for bunny ears
Look at V6 for inverted T-wave

57
Q

Bundle branch blocks

A
58
Q

What does an EKG record?

A

the electrical activity of the heart muscle (myocardium).

Information recorded represents the electrical activity of contraction of the myocardium

59
Q

What is the dominant pacemaker of the heart normally?

A

SA node:
Initiated a wave of depolarization that spreads outwards, stimulating the atria to contract as the circular wave advances.

It’s pacing activity is known as sinus rhythm

60
Q

What is Automaticity?

A

The generation of pacemaking stimuli.

The ability of the SA node to generate pacemaking stimuli

61
Q

QRS

A

Ventricular depolarization
(<.12 seconds)

62
Q

Q wave

A

Septal depolarization

63
Q

P wave

A

The depolarization and contraction of both atria

64
Q

T-wave

A

The final “rapid phase” of ventricular repolarization

K+ ions leaving the myocytes

65
Q

PR interval

A

The impulse from the SA node to AV node and to the Bundle of His

Should sit on the isoelectric line

66
Q

ST segment

A

Initial repolarization

“Plateau phase” of ventricular repolarization

The horizontal segment of baseline that follows the QRS complex

67
Q

QT interval

A

Represents the duration of ventricular systole.

Measures from the beginning of QRS until the end of the T-wave

68
Q

What is the QT interval a physiologic marker of?

A

A good indicator of repolarization.

Pts w hereditary long QT interval syndromes are vulnerable to dangerous rapid ventricular rhythms

69
Q

J-point:

A

located at the end of the QRS where the T-wave begins

70
Q

R-R interval

A

The entire cardiac cycle

71
Q

Slowing of the wave of depolarization at the AV node allows what to happen?

A

When the wave of atrial depolarization enters the AV node, depolarization slows, producing a brief pause, thus allowing time for the blood in the atria to enter the ventricles.

Slow conduction through the AV node is carried by calcium ions

AV node is the only electrical conduction pathway between the atria and the ventricles

72
Q

What are the Limb leads

A

I, II, III, aVL, aVR, aVF

73
Q

What are the chest/precordial leads

A

V1-V6

74
Q

What is Einthoven’s Triangle?

A

Electrodes are placed on the right arm, left arm, and left leg. A pair of electrodes are used to record a lead.

Einthoven used these 3 locations for limb electrodes. They remain the conventional standard for recording the EKG.

Two electrodes are used to record a lead. A different pair is used for each lead.

75
Q

What information can we gain by looking at multiple leads of the electrical impulse of the heart?

A

It may be difficult to see a specific wave in a given lead, but with different lead positions, it is certain to show up better in other leads

76
Q

What are the things that you should check on every EKG?

A

Rate, Rhythm, Axis, Hypertrophy, Infarction

77
Q

Describe 2 different ways to measure the heart rate on the EKG

A

Find an R-wave that starts on the heavy black line. The following heavy black lines should be noted as 300, 150, 100, 75, 60, 50. Where the R-wave falls next determines the rate. Triplet method: 300, 150, 100 then 75, 60, 50

Box method: 300/ number of boxes between R waves
10 second rhythm strip: number of R-waves x 6

78
Q

Describe a simple way to determine the axis of ventricular depolarization.

A

We can demonstrate the general direction of the movement of depolarization by using a vector (arrow).

The vector shows the direction in which depolarization is moving.

When interpreting EKG’s a vector shows the general direction of depolarization in the heart.

79
Q

What things may cause axis deviation?

A

-Obesity (up and to the left)
-Tall, slender people may have a “vertical heart” (down and to the right)
-Hypertrophy (deviates towards the ventricle that is hypertrophied)
-MI (vector points away from the infarct bc dead tissue can’t depolarize)

80
Q

The tail of the vector is the______

A

AV node

81
Q

There is an increased depolarization in a ________

A

Hypertrophied ventricle

82
Q

The mean QRS vector should point downward and to the patient’s ______

A

Left

In the 0-degree to +90-degree range.

83
Q

Lead 1 is best for detecting______

A

right axis deviation

84
Q

What lead would you look at to determine atrial hypertrophy?

A

V1

85
Q

What would you see on the 12 lead EKG with Right Ventricular Hypertrophy?

A

The P-wave is usually diphasic (both positive and negative)

If the initial component of a diphasic P-wave in V1 is the larger then this is right atrial enlargement

If the height of the P-wave in any of the limb leads exceeds 2.5mm (even if it’s not diphasic) suspect right atrial enlargement)

86
Q

What would you see on the 12 lead EKG with Left Ventricular Hypertrophy?

A

Large S in V1 and large R in V5, T-wave inversion w T-wave asymmetry

QRS complexes that are exaggerated amplitude, both in height and in depth, especially in the chest leads.

Even deeper S wave in V1.

(There is a left axis deviation, and often the vector is displaced in a leftward direction in the horizontal plane.)

87
Q

What EKG changes could be seen with myocardial ischemia?

A

Characterized by symmetrically inverted T-waves

88
Q

What EKG changes could be seen with myocardial infarction?

A

ST elevation must be at least 2 mm in V2 and V3 for it to be a true ST elevation
Must be seen in 2 contiguous leads
Can have ST depression (.5 mm in 2 contiguous leads)
Upsloping ST elevation
Hyperacute T-wave

89
Q

Anterior myocardial infarction

A

Always check V1 and V2 for ST elevation and Q waves

Due to an occlusion of the LAD

90
Q

Inferior myocardial infarction

A

Qs in II, III aVF

Due to an occlusion in the right or left coronary arteries

91
Q

Lateral myocardial infarction

A

Qs in lateral leads 1, aVL

Caused by an occlusion of the circumflex (LCX) branch of the left coronary artery

92
Q

Posterior myocardial infarction

A

Always check V1 and V2 for ST depression and large R waves
Usually caused by an occlusion of RCA or one of its branches

93
Q

What unusual wave might be seen on the EKG with hypokalemia?

A

T-wave becomes flat (or inverted) and a U wave appears

94
Q

What EKG changes would you expect with hyperkalemia?

A

P-wave flattens down, the QRS complex widens, T-waves become peaked

95
Q

In what condition would you expect to see a Delta wave on the EKG?

A

When there is an extra pathway conducting electricity from atria to the ventricles - Seen in WPW syndrome

96
Q

Define axis

A

Refers to the direction of depolarization as it passes through the heart