ECG III and J Point Flashcards
(112 cards)
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 QRS deflection, this is the direction of the lead vectorYou 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
T OR F: The concept of the electric axis of the heart usually denotes the average direction of the electric activity throughout ventricular activation
TRUE
26
When determining electric axis, use 3 easy steps.
1 ) Find most biphasic 2 ) Find which perpendicular to this lead3 ) If perpendicular lead has upward deflection then electric axis +If perpendicular lead has downward deflection then electric axis -
27
Perfusion is based on what?
Pressure and flow
28
Flow is based from what?
Volume / Time
29
Left axis deviation (LAD) ischemic signs?
Hypertrophy from ECGTachycardia
30
T or F: Electrical blocks are not pathological?
TRUE
31
What is the avg voltage of the R wave?
1 mV
32
Pacing spikes from A-pacer pacemakers paces what part of the heart?
The atriaSo conduction comes from atrium and then would be normal
33
V-paced pacemakers show what on an ECG?
Widened QRSPacing spikes not seen
34
ECG use what kind of amplifiers?
Differential amplifiers Takes + and - input signals and converts to alpha output signal (+ - )(alpha = gain of the amplifier)EX : + = 3v- = 5vOutput = (+ - ) = 3 - 5 = -2 v
35
Why is there a RL electrode?
It acts as an electrical reference for the ECG amplifierIt improves the common mode rejection
36
T or F: RL is always used in ECG axis evaluation therefore can go anywhere on the body
FALSE, it is never used in ECG axis evaluation
37
What is CMRR?
Common mode rejection ratio
38
What is CMNR?
Common mode noise reduction
39
Can CMNR of amplifiers make up for the electrode impedance imbalance
No they cannot
40
What is the common interference for EKG?
60 hz
41
What is a high pass filter?
Rejects low frequency signals
42
What is a low pass filter?
Rejects high frequency signals
43
What is a band pass filter?
Rejects signals that are too high and too lowMost ECG filters today are band pass
44
What is the approximate amplitude of the ECG waveform?
1 mV
45
How many volts does wall electrical outlet put out?
120 V
46
How many volts does electrosurgery signal put out?
60 to 400 V
47
The ECG is highly susceptible to what other noise?
EMG muscular noise
48
What is amplifier gain?
The gain is the amount of amplification
49
What is gain equation?
Gain = Output Amplitude / Input amplitude
50
A gain of 10 means what?
THe output signal is ten times larger that then input signal
51
A gain of 0.5 means what?
The output signal is 1/2 of the amplitude of the input signal
52
What does a cardiotachometer do?
Device that counts the HR
53
What range on display get rid of EMG activity?
0.05 Hz
54
What range on display gets rid of 60 Hz interference?
40 Hz
55
What is the range of signal frequencies that detects QRS?
5-30 Hz
56
What is the range of signal frequencies that detects arrhythmias and ST segments?
0.05-60 Hz
57
Pacemaker detection will not be detected until what frequency range?
1500 - 5000 Hz
58
White lead color?
RA
59
LA lead color?
Black
60
Red lead color?
LL
61
Chest leads color?
Brown
62
Reference lead color?
Green
63
Which type of filter uses band pass and high pass filters ?
Band reject filters
64
AHA required frequency response for diagnostic purposes for adults?
0.05 Hz to 150 Hz
65
AHA required frequency response for diagnostic purposes for pediatric population?
0.05 to 250 Hz
66
T or F: The bovie operates at high frequencies and this is why you cannot be shocked
TRUE
67
T or F: The return pad is small to help prevent burns from bovie
FALSE, pad is large
68
What law is used when monitoring the EKG in the MRI?
Faraday's law
69
Which interference will go away after giving the patient a NMB drug?
EMG interferenceFasciculation will cause much larger interference for short period of time
70
What is the J point?
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 potentialLocated at the end of the QRS complex
71
S-T segment starts when?
60 - 80 msec after J point
72
What is the std. sweep speed on monitor?
25 mm / sec
73
What is considered/thought to be the true isoelectric line / point?
Point between P & Q
74
Is 1mm of depression or 1mV or depression more significant?
1mVIf you have 1mV depression pray and call for help and then run
75
The most common used parameter for measuring _____________ is 60 msec post J-point?
ST segment
76
Other than ST segment depression or elevation, what other criteria must be met for diagnosis of infarct?
Q wave > 1/3 the amplitude of the entire QRS complex or have Width of 1mm
77
Which lead gives you the greatest possibility of detecting LV Ischemia when we (practitioners) are the detectors
V52nd is V4
78
V5 will give you what percentage sensitivity of detecting ST segment ?
75%
79
What two lead combination increase ST sensitivity?
V4 and V5 :::::::: 90%
80
What three lead combination increase ST sensitivity?
II and V4 and V5 ::::: 96%
81
What four lead combination increase ST sensitivity?
II , V3 , V4 , V5 ::::::: 100%
82
If you have ST segment elevation, what you should you always assume?
Assume Heart not getting enough O2, work to get O2 to heart
83
Hyper calcemia will show what on ECG waveform?
Q-T short segment
84
Hypocalcemia will show what on ECG waveform?
Prolonged Q-T segment
85
When using an esophageal ECG lead, what are you mostly monitoring?
The posterior heart, which is usually left heart
86
T OR F: Esophageal ECG recordings provide very little volume conduction so is very similar to electrodes placed directly on the heart?
TRUE
87
What are the best determinates for HR counting?
1) Arterial pressure waveform2) Pulse Ox3) ECG
88
Why is ECG so unreliable when it comes to counting HR?
-MIssed beats because of respiration's-Counting more often than each beat
89
What wave is responsible for ST Elevation or depression?
T wave variations(hence why Peak T waves indicate the onset of ischemia)
90
In most pt's, is the J point below, at, or above the isoelectric line?
At or below
91
Does J point elevation have any pathological implications whatsoever?
NO, nothing pathlogical
92
T or F: J point elevation is very uncommon in young, healthy individuals
FALSE, is very common
93
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.
IF the elevation makes a unhappy/sour/upside down smiley face then it is myocardial disease
94
Always remember, ANY VARIATION FROM THE NORM SHOULD BE LOOKED AT AS A POSSIBLE INDICATION OF ISCHEMIA
and now good god i hate EKG.If you all want to add anything please feel free
95
What signal is present everywhere on the body that the differential amplified will see at both input terminals simultaneously
Common Mode Signal
96
When signal at both input terminals exactly the same, output will be zero is called...
Common Mode Rejection
97
A higher CMRR is better. True or false?
True
98
If one electrode impedance is high, then input signals do not appear same at amplified, thus common mode signal appears. This is known as what?
Electrode Impedance Imbalance
99
60 Hz interference comes from:
Electrode Impedance Imbalance
100
What is the signal amplitude of EEG?
0.01 to 0.1 mV
101
What is the 60 Hz common mode signal amplitude?
10-500 mV
102
What is the amplitude of a wall outlet?
120 V
103
What is the amplitude of an electrocautery signal?
60-400 V
104
What are common ECG artifacts?
Basically anything electrical like:
```
EMG noise
Power line
LIM
Electrocautery
MECHANICAL VENT
MRI
IV pump
Warmers
SKIN IMPEDANCE
ECG ELECTRODES, CABLES
```
105
What:
Allows low frequency
Rejects high frequency
Low Pass Filter
106
What filter retains ST segment info?
Low Pass Filter
107
What filter:
Removes baseline wandering
Removes electrode half cell potentials?
High Pass Filter
108
What filter rejects specific frequencies?
Notch filter
109
An automated ST segment analyzer filters regardless of current settings. True or false?
True
110
What is lost when frequency is changed from 0.5 to 1.0 Hz on ECG?
ST segment
111
What is lost when frequency is changed to 100 to 30 Hz on ECG?
Loss of R amplitude
112
What information does the ECG provide well at 0.05-100 Hz? (4)
NSR
ST segment elevation
ST segment depression
BBB
