ECG Flashcards

1
Q

what are the 3 unique properties of cardiac myotcytes

A
  1. automaticity
  2. rhythmicity
  3. conductivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the inherent discharge rate of the SA node?

A

60-100 times per min

this rhythmicity creates the sinus rhythm

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

what is the inherent discharge rate of the AV node?

A

40-60x per minute

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

what is the inherent discharge rate of the His-Pukinje fibers?

A

30-40 times per min

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

T/F: the faster/higher discharge rate predominates

A

TRUE

autonomic influence > SA > AV > Purkinje fibers

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

what does the P wave depict?

A

atrial depolarization

the impulse is spread to the L atrium via the Bachmann bundle

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

what does the PR interval depict?

A

the spread of depolarization reaches the AV, there is a slight delay

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

where are bundle branches located?

A

interventricular septum

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

what does the QRS complex reflect?

A

ventricular depolarization

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

what does the T wave represent?

A

ventricular repolarization

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

what is the absolute refractory period?

A

the period in which the heart cannot be stimulated to contract

represented by the interval from the beginning of the QRS complex to the apex of the T wave

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

the standard 12 lead ECG consists of what?

A

6 limb leads + 6 chest leads

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

List the 6 different limb leads

A
  • standard limb leads → I, II, III
  • augmented limb leads → aVR, aVL, aVF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

the limb leads provide a view of the heart in the ______________

A

frontal plane

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

where is V1 placed

A

4th intercostal space

R sternal border

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

where is V2 placed?

A

4th intercostal space

L sternal border

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

where is V3 placed?

A

between leads V2 and V4

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

where is V4 placed?

A

5th intercostal space in midclavicular line

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

where is V5 placed?

A

horizontally even with V4

but in the anterior axillary line

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

where is V6 placed?

A

horizontally even with V4 and V5 but in the midaxillary line

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

ECG chest leads provide a view of the heart in the ___________

A

horizontal plane

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

which leads are placed over the R side of the heart?

A

V1 and V2

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

which leads are placed over the interventricular septum?

A

V3 and V4

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

what do leads V5 and V6 demonstrate?

A

changes on the left side of the heart

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

phrase to remember where to place telemetry leads

A

white right

snow over grass

brown ground

smoke over fire

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

when performing a single lead assessment, what are you looking for?

A
  1. Heart rhythm or rate
  2. normal waveforms
  3. abnormal waveforms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

which lead is frequently used if you perform a single lead assessment?

A

chest lead 5

OR

limb lead II

*they both provide a picture of the LV

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

on an ECG strip, how many squares equal 1 and 6 seconds?

A

5 big squares = 1 sec

30 big squares = 6 sec

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

Methods of determining heart rate from an ECG strip

A
  • 300, 150, 100, 75, 60, 50 method
  • count the number of large boxes between 2 adjacent R waves than 300/this count
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

T/F: single limb monitoring can accurately assess rate and rhythm only

A

TRUE

31
Q

List steps of assessing the cardiac cycle on an ECG

A
  1. evaluate P wave (normal, upright, all look the same?)
  2. evaluate P-R interval
  3. evaluate QRS complex
  4. evaluate QRS interval
  5. evaluate T-wave
  6. evaluate R-R interval
  7. evaluate heart rate
  8. observe the pt and evaluate any symptoms
32
Q

what is the normal duration for the PR interval?

A

0.12-0.20 seconds

33
Q

what is the normal duration for the QRS interval?

A

0.06-0.10 seconds

34
Q

ECG abnormalities that we can notice

A
  1. First Degree AV block
  2. Second Degree AV block
    1. Wenckeback (Mobitz I)
    2. Mobitz II
  3. Third Degree AV block
  4. Atrial arrhythmias
    1. paroxysmal atrial tachycardia
    2. paroxysmal supraventricular tachycardia
    3. atrial fibrillation
  5. Ventricular arrhythmias
    1. premature ventricular complexes
    2. ventricular tachycardia
    3. ventricular fibrillation
35
Q

what is a first degree AV block?

A

occurs when the impulse is initiated in the SA node but is delayed on the way to the AV node

the delay may be initiated in the AV node itself, and the AV conduction time is prolonged

36
Q

what does a first degree AV block look like on an ECG strip?

A

prolonged PR interval

“if the R is far from the P than you have first degree”

37
Q

T/F: HR is usually within normal limits in a First Degree AV block

A

TRUE

may be lower than 60 bpm

38
Q

what is a second degree AV block?

A

transient disturbance that occurs high in the AV junction and prevents conduction of some of the impulses through the AV node

39
Q

what does a second degree AV block look like on an ECG?

A

initially P wave precedes each QRS complex but eventually a P wave may stand alone (conduction is blocked)

progressive lengthening of the PR interval occurs

as the PR interval increases a QRS complex will eventually be dropped

40
Q

what is the difference between a Wenckebach and Mobitz 2?

A

both types of second degree AV blocks

  • Wenckebach (Mobitz 1) = ECG signs of gradual exhaustion of impulse conduction. Manifests as a gradual increase of PR interval before a block occurs
  • Mobitz II = sporadically occurring blocks, w/o any Wenckebach phenomenon
41
Q

describe a second degree AV block (Mobitz II)

A

P waves “march through” at a constant rate

“if some p’s don’t get through, than you have Mobitz II”

42
Q

what is a third degree AV block?

A

no impulses that are initiated above the ventricles are conducted to the ventricle

atria and ventricles fire at their own inherent rate

“If the Ps and Qs don’t agree, than you have 3rd degree”

43
Q

how would the heart rate look in a 3rd degree AV block?

A

depends on the latent ventricular pacemaker and may range from 30-50 bpm

44
Q

how are 1st degree AV blocks treated?

A

these are benign and usually not treated

45
Q

how are 2nd degree AV blocks treated?

A
  1. dependent on the type of 2nd degree block
  2. no treatment necessary OR
  3. pacemaker placement
  4. result of an MI
46
Q

how are 3rd degree AV blocks treated?

A

these are life threatening

  1. MI, degeneration of the conducting system
  2. permanent pacemaker placement
  3. medical emergency
47
Q

how can atrial arrhythmias present on an ECG?

A
  1. P waves may be present but may be merged with the previous T wave
  2. PR intervals may be difficult to determine but are less than 0.2 seconds
  3. QRS complexes are identical unless there is an aberration
  4. QRS duration between 0.06 and 0.10 sec
  5. RR intervals are usually regular and may show starting and stopping of the PAT
48
Q

factors that contribute to paroxysmal atrial tachycardia

A
  1. emotional factors
  2. overexertion
  3. hyperventilation
  4. K+ depletion
  5. caffeine
  6. nicotine
  7. aspirin sensitivity
  8. rheumatic heart disease
  9. mitral valve dysfunction
  10. PE
49
Q

if paroxysmal atrial tachycardia continues for a period of time what symptoms may develop?

A
  1. dizziness
  2. weakness
  3. SOB
50
Q

define atrial fibrillation

A

defined as an erratic quivering or twitching of the atrial muscle caused by multiple ectopic foci in the atria that emit electrical impulses constantly

51
Q

describe how atrial fibrillation may look on an ECG

A
  1. P waves are absent, thus leaving a flat or wavy baseline
  2. the RR interval is characteristically defined as irregularly irregular
  3. the QRS duration is between 0.06 and 0.10 second
52
Q

what does ventricular response look like in atrial fibrillation?

A

may be normal, slow or too rapid

but typically it is more rapid

53
Q

atrial fibrillation is typically associated with what things?

A
  1. advanced age
  2. CHF
  3. ischemia or infarction
  4. cardiomyopathy
  5. digoxin toxicity
  6. drug use
  7. stress or pain
  8. rheumatic heart disease
  9. renal failure
54
Q

atrial fibrillation is typically associated with what things?

A
  1. advanced age
  2. CHF
  3. ischemia or infarction
  4. cardiomyopathy
  5. digoxin toxicity
  6. drug use
  7. stress or pain
  8. rheumatic heart disease
  9. renal failure
55
Q

T/F: atrial fibrillation is life threatening

A

FALSE

not considered life-threatening unless the HR is elevated at rest

56
Q

what is an atrial kick?

A

decrease in CO by 15-30%

57
Q

with atrial fibrillation there is a potential for developing _________

A

mural thrombi

58
Q

what are PVCs?

A

premature ventricular complexes

occur when an ectopic focus originates an impulse from somewhere in one of the ventricles

59
Q

what does the QRS look like in a PVC?

A

classically described as wide and bizzare looking QRS without a P wave and followed by a complete compensatory pause

60
Q

how are PVCs treated?

A

depends on the underlying cause, the frequency and severity of the PVCs, and the symptoms associated with them

61
Q

when are PVCs considered life threatening?

A
  1. paired together
  2. multifocal in origin
  3. more frequent than 6 per minute
  4. land directly on the T wave
  5. present in triplets or more
62
Q

when are PVCs considered benign?

A

when they are isolated, w/o symptoms, and fewer than 6 per minute

63
Q

what is V-tach?

A

ventricular tachycardia

  • defined as a series of 3 or more PVCs in a row
  • torsades de pointes
  • occurs because of rapid firing by a single ventricular focus w/increased automaticity
64
Q

how does V-tach look on an ECG?

A
  1. P waves are absent
  2. three of more PVCs in a row
  3. associated with a prolonged QT interval
  4. QRS complexes are wide and bizarre
  5. rate is between 100-250 bpm
65
Q

V-tach can be a precursor to _______

A

ventricular fibrillation

66
Q

what are some causes of V-tach?

A
  1. ischemia
  2. acute infarction
  3. CAD
  4. hypertensive heart disease
  5. reaction to meds
67
Q

how is v-tach treated?

A
  1. cardioversion
  2. defibrillation
  3. lidocaine, bretylium tosylate (Bretylol) or procainamide (Pronestyl)
68
Q

someone who remains conscious with V-tach may appear _______________

A

extremely lightheaded or near syncope

69
Q

when is V-tach considered a medical emergency?

A

when CO is severely diminished and V-tach has converted to V-FIb

70
Q

define V-Fib

A

Ventricular Fibrillation

an erratic quivering of the ventricular muscle resulting in no CO

caused by multiple ectopic foci firing creating asynchrony

71
Q

how would an ECG look with V-Fib?

A

a grossly irregular up and down pattern fluctuating of the baseline in an irregular zigzag pattern

72
Q

T/F: V-Fib is a medical emergency?

A

TRUE

treat with defibrillation as quickly as possible followed by cardiopulmonary resuscitation, supplemental O2 and injection of meds

73
Q

how do you determine the presence of hypertrophy by looking at an ECG?

A

look at the voltage in V1 and V5

  1. R ventricular hypertrophy
    1. a large R wave in V1 which gets progressively smaller in V2, V3, and V4
  2. L ventricular hypertrophy
    1. a large S wave in V1 and a large R wave in V5 that have a combined voltage of greater than 35 mV
74
Q

how do you determine the presence of ischemia via an ECG?

A
  1. an inverted T-wave
  2. S-T segment depression