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Flashcards in ECG III and J POINT Deck (94)
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1
Q

ECG waveform segment?

A

Between waves

2
Q

ECG waveform interval?

A

Includes waves

3
Q

P wave last how long?

A

0.08 s

4
Q

P-R segment last how long?

A

0.08 s

5
Q

P-R interval last how long?

A

0.16 s

6
Q

QRS complex last how long?

A

0.08 s

7
Q

S-T segment last how long?

A

0.12 s

8
Q

T-wave last how long?

A

0.16 s

9
Q

S-T interval last how long?

A

0.28 s

10
Q

Q-T interval last how long?

A

0.36 s

11
Q

Which wave is the first - (negative) wave?

A

Q wave

12
Q

For the Q wave to be pathological, what 2 things must be present?

A

Must be wider than 1 box (0.04 sec)

Must be 1/3 height of the R wave

13
Q

The p wave represents what?

A

The electrical activity of the contraction of both atria

14
Q

The total QRS complex represents what?

A

The electrical activity of ventricular contraction

15
Q

Which wave will ALWAYS be positive?

A

The R wave

16
Q

Can you have a wave that does not contain an R wave?

A

Yes, is a large negative deflection known an QS wave

17
Q

What is the normal range of the electric axis of the frontal plane?

A

-30 and +110

18
Q

What is the normal range of the electric axis of the transverse plane?

A

+30 and -30

19
Q

How do you approximate the electric axis direction from a 12-lead ECG?

A

Find which lead has the most positive or negative QRS deflection, this is the direction of the lead vector
You check this by observing which lead has the most biphasic QRS complex, then see which lead is perpendicular to the axis

20
Q

Deviation of the electric axis to the right means what?

A

Increased electric activity in the right ventricle due to increased RV mass

21
Q

What causes increased RV mass?

A
  • Chronic obstructive lung disease
  • Pulmonary emboli
  • Congenital heart Dz
  • Disorders causing pulmonary hypertension or cor pulmonale
22
Q

Deviation of the electric axis to the left is an indication of what?

A

Increased electric activity in the left ventricle due to increased LV mass

23
Q

What causes increased LV mass?

A
  • Hypertension
  • Aortic stenosis
  • Ischemic heart dz
  • Intraventricular conduction defect
24
Q

Deviation of the electric axis could result from mechanical displacement of the heart from normal position, what could cause this?

A
  • Pregnancy
  • Pneumothoraxel
  • Spinal deformation
25
Q

T OR F: The concept of the electric axis of the heart usually denotes the average direction of the electric activity throughout ventricular activation

A

TRUE

26
Q

When determining electric axis, use 4 easy steps.

A

1 ) Find most biphasic
2 ) Find which perpendicular to this lead
3 ) If perpendicular lead has upward deflection then electric axis +
If perpendicular lead has downward deflection then electric axis -
4) Find greatest QRS complex in either + or - direction to get most accurate degrees

27
Q

Perfusion is based on what?

A

Pressure and flow

28
Q

Flow is based from what?

A

Volume / Time

29
Q

Left axis deviation (LAD) ischemic signs?

A

Hypertrophy from ECG

Tachycardia

30
Q

T or F: Electrical blocks are not pathological?

A

TRUE

31
Q

What is the avg voltage of the R wave?

A

1 mV

32
Q

Pacing spikes from A-pacer pacemakers paces what part of the heart?

A

The atria

So conduction comes from atrium and then would be normal

33
Q

V-paced pacemakers show what on an ECG?

A

Widened QRS

Pacing spikes not seen

34
Q

ECG use what kind of amplifiers?

A
Differential amplifiers 
Takes + and - input signals and converts to alpha output signal (+ - )
(alpha = gain of the amplifier)
EX : 
\+ = 3v
- = 5v
Output =  (+ - ) = 3 - 5 = -2 v
35
Q

Why is there a RL electrode?

A

It acts as an electrical reference for the ECG amplifier

It improves the common mode rejection

36
Q

T or F: RL is always used in ECG axis evaluation therefore can go anywhere on the body

A

FALSE, it is never used in ECG axis evaluation

37
Q

What is CMRR?

A

Common mode rejection ratio

38
Q

What is CMNR?

A

Common mode noise reduction

39
Q

Can CMNR of amplifiers make up for the electrode impedance imbalance

A

No they cannot

40
Q

What is the common interference for EKG?

A

60 hz

41
Q

What is a high pass filter?

A

Rejects low frequency signals

42
Q

What is a low pass filter?

A

Rejects high frequency signals

43
Q

What is a band pass filter?

A

Rejects signals that are too high and too low

Most ECG filters today are band pass

44
Q

What is the approximate amplitude of the ECG waveform?

A

1 mV

45
Q

How many volts does wall electrical outlet put out?

A

120 V

46
Q

How many volts does electrosurgery signal put out?

A

60 to 400 V

47
Q

The ECG is highly susceptible to what other noise?

A

EMG muscular noise

48
Q

What is amplifier gain?

A

The gain is the amount of amplification

49
Q

What is gain equation?

A

Gain = Output Amplitude / Input amplitude

50
Q

A gain of 10 means what?

A

THe output signal is ten times larger that then input signal

51
Q

A gain of 0.5 means what?

A

The output signal is 1/2 of the amplitude of the input signal

52
Q

What does a cardiotachometer do?

A

Device that counts the HR

53
Q

What range on display get rid of EMG activity?

A

0.05 Hz

54
Q

What range on display gets rid of 60 Hz interference?

A

40 Hz

55
Q

What is the range of signal frequencies that detects QRS?

A

5-30 Hz

56
Q

What is the range of signal frequencies that detects arrhythmias and ST segments?

A

0.05-60 Hz

57
Q

Pacemaker detection will not be detected until what frequency range?

A

1500 - 5000 Hz

58
Q

White lead color?

A

RA

59
Q

LA lead color?

A

Black

60
Q

Red lead color?

A

LL

61
Q

Chest leads color?

A

Brown

62
Q

Reference lead color?

A

Green

63
Q

Which type of filter uses band pass and high pass filters ?

A

Band reject filters

64
Q

AHA required frequency response for diagnostic purposes for adults?

A

0.05 Hz to 150 Hz

65
Q

AHA required frequency response for diagnostic purposes for pediatric population?

A

0.05 to 250 Hz

66
Q

T or F: The bovie operates at high frequencies and this is why you cannot be shocked

A

TRUE

67
Q

T or F: The return pad is small to help prevent burns from bovie

A

FALSE, pad is large

68
Q

What law is used when monitoring the EKG in the MRI?

A

Faraday’s law

69
Q

Which interference will go away after giving the patient a NMB drug?

A

EMG interference

Fasciculation will cause much larger interference for short period of time

70
Q

What is the J point?

A

Exactly the point at which the wave of depolarization completes passage through the heart.
It contains no electrical current flow, and such by definition become zero potential
Located at the end of the QRS complex

71
Q

S-T segment starts when?

A

60 - 80 msec after J point

72
Q

What is the std. sweep speed on monitor?

A

25 mm / sec

73
Q

What is considered/thought to be the true isoelectric line / point?

A

Point between P & Q

74
Q

Is 1mm of depression or 1mV or depression more significant?

A

1mV

If you have 1mV depression pray and call for help and then run

75
Q

The most common used parameter for measuring _____________ is 60 msec post J-point?

A

ST segment

76
Q

Other than ST segment depression or elevation, what other criteria must be met for diagnosis of infarct?

A

Q wave > 1/3 the amplitude of the entire QRS complex or have Width of 1mm

77
Q

Which lead gives you the greatest possibility of detecting LV Ischemia when we (practitioners) are the detectors

A

V5

2nd is V4

78
Q

V5 will give you what percentage sensitivity of detecting ST segment ?

A

75%

79
Q

What two lead combination increase ST sensitivity?

A

V4 and V5 :::::::: 90%

80
Q

What three lead combination increase ST sensitivity?

A

II and V4 and V5 ::::: 96%

81
Q

What four lead combination increase ST sensitivity?

A

II , V3 , V4 , V5 ::::::: 100%

82
Q

If you have ST segment elevation, what you should you always assume?

A

Assume Heart not getting enough O2, work to get O2 to heart

83
Q

Hyper calcemia will show what on ECG waveform?

A

Q-T short segment

84
Q

Hypocalcemia will show what on ECG waveform?

A

Prolonged Q-T segment

85
Q

When using an esophageal ECG lead, what are you mostly monitoring?

A

The posterior heart, which is usually left heart

86
Q

T OR F: Esophageal ECG recordings provide very little volume conduction so is very similar to electrodes placed directly on the heart?

A

TRUE

87
Q

What are the best determinates for HR counting?

A

1) Arterial pressure waveform
2) Pulse Ox
3) ECG

88
Q

Why is ECG so unreliable when it comes to counting HR?

A
  • MIssed beats because of respiration’s

- Counting more often than each beat

89
Q

What wave is responsible for ST Elevation or depression?

A

T wave variations

hence why Peak T waves indicate the onset of ischemia

90
Q

In most pt’s, is the J point below, at, or above the isoelectric line?

A

At or below

91
Q

Does J point elevation have any pathological implications whatsoever?

A

NO, nothing pathlogical

92
Q

T or F: J point elevation is very uncommon in young, healthy individuals

A

FALSE, is very common

93
Q

Look at the slide in powerpoint, but remember , if the S-T elevation is such that it makes a smiley face, then it is OK.

A

IF the elevation makes a unhappy/sour/upside down smiley face then it is myocardial disease

94
Q

Always remember, ANY VARIATION FROM THE NORM SHOULD BE LOOKED AT AS A POSSIBLE INDICATION OF ISCHEMIA

A

and now good god i hate EKG.

If you all want to add anything please feel free