EKG Flashcards
1
Q
Graphical recording of summated electrical activities of heart by surface electrodes?
A
electrocardiogram
2
Q
machine that records ECG
A
electrocardiograph
3
Q
how do you make a electrocardigraphic lead?
A
Positive electrode from positive pole and negative electrode from negative pole will pick up electrical activities produced by heart
4
Q
how many leads are there in total?
A
12
5
Q
in what two major groups are leads divided into?
A
Limb Leads
Unipolar Chest Leads/Precardial Leads
6
Q
what are the 2 groups of limb leads?
A
3 are bipolar limb leads
3 are augmented unipolar limb leads
7
Q
what are the 3 are bipolar limb leads?
A
Lead I, Lead II, Lead III
8
Q
what are the 3 are augmented unipolar limb leads?
A
aVR, aVL, aVF
9
Q
what do augmented unipolar limb leads do?
A
Augment electrical potential to match electrical potential of bipolar limbs
10
Q
limb leads will look at electrical activity of the heart from what view?
A
frontal plane
11
Q
Unipolar Chest Leads/Precardial Leads will look at the electrical activity of the heart from what view?
A
horizontal plane view
12
Q
what are the Unipolar Chest Leads/Precardial Leads ?
A
V1
V2
V3
V4
V5
13
Q
where are the Unipolar Chest Leads/Precardial Leads placed on the body?
A
o V1: 4th ICS, right sternal border
o V2: 4th ICS, left sternal border
o V3: between V2 and V4
o V4: 5th ICS, midclavicular line
o V5: anterior axillary line
14
Q
where do you place limb leads (normal and augmented) in the body and at what angle?
A
o Lead 1: right arm is negative; left arm is positive; angle of orientation is 0 degrees.
o Lead 2: right arm is negative; left leg is positive; angle of orientation is 60 degrees.
o Lead 3: left arm is negative; right leg is positive; angle of orientation is 120 degrees.
o aVL: left arm is positive, all other limbs are negative; angle of orientation is -30 degrees
o aVR: right arm is positive, all other limbs are negative; angle of orientation is -150 degrees
o aVF: legs are positive, all other limbs are negative; angle of orientation: 90 degrees
15
Q
what is the Anatomical Group of V1 and V2?
A
Septal
16
Q
what is the Anatomical Group of V3 and V4?
A
Anterior
17
Q
what is the Anatomical Group of Lead 1, aVL, V5, V6?
A
lateral
18
Q
what is the anatomical group of Lead II, Lead III, aVf ?
A
Inferior
19
Q
what is the anatomical group of aVR ?
A
none
20
Q
what is P wave?
A
when SA node generates impulse – spreads to atria,
21
Q
what is QRS?
what is Q?
what is R?
what is S?
A
depolarization of ventricles
Q = septal depolarization
R = depolarization of apex
S = depolarization of base of heart
22
Q
Which ion conductance is maximum during QRS?
A
sodium
23
Q
After ventricular depolarization, ventricles will remain how? why?
A
depolarized before they get repolarized; no potential is recorded; corresponds to plateau phase of ventricular action potential.
24
Q
what is T wave?
A
Ventricular repolarization
25
T wave represents which phase of action potential of fast cells?
corresponds to Phase 3 [point directly after T wave]
26
Which ion conductance is maximum during T wave?
Potassium conductance
27
which part of the heart repolarizes first?
base
28
what is the last part of the heart to depolarize?
base
29
how long does PR Interval last?
.1-.2 segs
30
in ecg, from where to where is PR Interval?
m beginning of P wave to beginning of QRS
31
what is the PR interval?
time duration for impulse to go from SA node to ventricular muscle
32
what happens if impulse takes longer to get through AV node?
PR interval is prolonged and PR segment is prolonged with delayed conduction
33
what can cause the PR interval to be prolonged as well as the PR segment leading to delayed conduction ?
parasympathetics can cause a negative dromotrophic
Ex: Beta blockers and calcium channel blockers can also delay conduction through AV node = decreases velocity of conduction
34
what does it mean if the PR interval is Greater than 0.20 sec ?
prolonged PR interval = 1st degree heart block
35
from where to where does the PR segment extend?
between the end of P wave to beginning of QRS
36
how do you calle the time interval between the PR segment?
Time interval is called AV Delay
37
what does AV delay mean?
time taken by impulse to get through AV node, represents AV nodal conduction
38
what are Septal Q Waves?
produced by depolarization of interventricular septum
39
how long does septal Q waves last?
normal duration is less than 0.04 seconds or less than 25% of the amplitude of R wave
40
what does it mean if 25% or more in amplitude of R wave?
pathological Q wave seen in myocardial infarction
41
what if you see a septal Q wave greater than 0.4 seconds in width [one small square] and/ greater than 2mm in depth [two small squares]?
pathological Q wave, seen in myocardial infarction
42
how long does the QRS Interval last?
lasts 0.08 – 0.10 seconds
43
how do we indentify the QRS interval?
from beginning of P wave to end of S wave
44
what does the QRS interval mean?
indicates duration of ventricular depolarization.
45
how long does the QT Interval last?
lasts 0.32 – 0.43 seconds normally
46
how do we identify the QT interval?
interval from beginning of Q wave to end of T wave;
47
what is the QT interval?
represents ventricular depolarization and ventricular repolarization.
48
how do we identify the ST Segment?
from the end of S wave to beginning of T wave,
49
what phase of action potential of fast cells in heart does ST segment correspond to?
to Phase 2 of action potential [plateau]
50
when do we see ST segment elevated?
in myocardial infarction
51
when do we see ST segment depressed?
angina
52
Which ion conductance is maximum during ST segment?
Calcium conductance.
53
what is the ST segment?
End of ventricular depolarization to start of ventricular repolarization
54
what is T Wave: ?
ventricular repolarization
55
what is the normal ecg Number of small squares/minute ?
1500 small squares or mm/min
56
what is the normal number of large squares/minute?
300 large squares/min
57
on the ecg, Horizontal axis measures what?
time
58
on the ecg, Vertical axis measures what?
voltage
59
a Small square on the horizontal line is equal to?
1mm x 1mm = 0.04 sec
60
a big square (5 small ones) on the horizontal line is equal to what?
0.2 segs
61
1 small square on the vertical line is how much?
Small square: 0.1 mV
62
1 big square on the vertical line is how much?
Large square: 0.5 mV
63
identify
1) PR segment
2) ST segment
3) PR interval
4) QT interval
64
calculate PR
PR = 0.16 segs
65
calculate QRS
0.08 segs
66
calculate QT interval
QT = 0.34
67
R-R interval gives duration of what?
1 cardiac cycle
68
how is Heart Rate calculated from ECG?
Using R-R interval; measure time duration between both R waves
Heart Rate = 60/[R-R interval]
69
What is the heart rate of this patient?
65 beats per min
70
what is the Rule of 300 ?
Divide 300 by the number of large squares between two neighboring QRS complexes
71
What is the heart rate?
75 bpm
72
when does the rule of 300 not work?
if rhythym is not regular
73
what is the 10 second rule?
Duration of rhythm strip: 10 seconds; count number of R waves, multiply by 6 to get number of beats per 60 seconds.
74
for what rhythym does the 10 second rule work for?
irrgeular beat rhythym
75
what is a normal sinus rhythym?
60-100
76
normal sinus rhythym arise from where?
form the SA node
77
normal sinus rhythym waves have what order?
Waves must be present in order of: P wave, QRS wave, T wave
78
what is Sinus Tachycardia ?
Heart rate is greater than 100 bpm
79
in sinus tachycardia, Impulses generated from where?
SA node
80
what waves are present in sinus tachycardia?
P, QRS, T waves
81
in Sinus Bradycardia, what waves are present?
P, QRS, T waves
82
what is sinus tachycardia?
Heart rate is less than 60 bpm
83
what is another name for normal sinus rhytym?
regular
84
What is a Normal rhythm or regular rhythym?
SA node produces impulses at regular interval, R-R interval is constant
85
what is a Irregular rhythm?
R-R intervals are unequal;
86
if P wave, QRS complex, and T wave are present, the irregular rhythm originates from where?
SA node
87
what is the QRS axis?
Represents the net overall direction of the heart’s electrical activity
88
what can the QRS axis be indicative of?
Indicative of ventricular enlargement, conduction blocks, position of heart.
89
what is the normal QRS axis?
Normal: between -30 degrees to +90 degrees
90
what does a Left Axis Deviation in the QRS axis mean?
indicative of left ventricular hypertrophy: between -30 degrees and -90 degrees
91
what does a Right Axis Deviation in the QRS axis mean?
- indicative of right ventricular hypertrophy: between +90 degrees and +180 degrees
92
under what normal circumstance can left axis deviation be seen?
pregnancy
93
what does the The Quadrant Approach use?
uses Lead I and unipolar augmented limb lead aVF used to calculate the QRS axis
94
is this a positive or negative lead?
positive
95
is this a positive or negative lead?
negative
96
is this a positive or negative lead?
equiphastic
97
how do you use the equiphastic approach?
1) Determine equiphasic lead on EKG [both positive and negative]
2) Find lead on hexaxial diagram
3) Find the perpendicular lead
4) Determine if it is positive or negative by locating it on the EKG
5) If the perpendicular lead is predominately (+) on the EKG, the axis goes in the samedirection as that lead. If the perpendicular lead is predominately (-), the axis is opposite in the direction of that lead.
98
what is a heart block?
delay in conduction of impulse; blockade of impulse in conducting pathway
99
how many heart blocks are there?
3
100
what is 1st degree heart block?
prolonged PR interval past 0.20 sec, slowed conduction through the AV node.
101
what is 2nd degree heart block ?
some impulses are not transmitted through the AV node [do not enter ventricular muscle]
102
what waves are absent in 2nd degree heart block?
no QRS complex, no t wave
103
what are the 2 types of 2nd degree heart block?
Mobitz I
Mobitz II
104
what is Mobitz I ?
PR interval progressively gets longer before missbeat; will see two consecutive P waves indicating a “dropped beat” [no QRS interval] progressive lengthening of PR interval before missbeat.
105
what is another name for Mobits I?
Wenckebach phenomenon
106
what is Mobitz II?
PR interval does not get progressively longer; missed QRS complex indicated by two consecutive P waves
107
what is another name for Mobitz II?
Non-Wenckebach
108
what is 3rd degree heart block ?
normally, same firing rate between entire conduction system initializing at the SA node; right coronary node supplies the AV node mostly – any infarction, AV node cannot conduct impulses from atria to ventricles
109
what is complete 3rd degree heart block?
No impulses make it to the ventricle from atria due to defect in conduction system in complete 3rd degree heart block
110
what is the heart rate (pulse rate) in 3rd degree heart block?
Pulse rate: 20-40 per minute
111
what is a Cardiac Arrhythmias ?
irregular initiation and conduction of impulses
Leads to irregular rhythm
112
what is Atrial Fibrillation ?
Multiple foci of impulses generated from atria and SA node and Atria do not contract as a single unit
113
what is Supraventricular tachycardia?
arrhythmia is originating above ventricle
114
what are the most common arrhythmia?
ischemia, valvular diseases, trauma, hyperthyroidism (increase in thyroid hormone increases number of beta receptors, increases affinity to catecholamines )
115
what is another name for 3rd degree heart block?
Stocks Adams syndrome
116
what waves are absent in ecg during Atrial Fibrillation ?
Absent A wave and X descent
117
how do you treat atrial fibrillation?
delay conduction velocity through AV node via Beta blockers
carotid massage that will increase baroreceptor activity, increases vagal activity, increasing parasympathetics, increasing AV nodal delay; cardioversion with drugs or electricity
118
what drugs can be used in atrial fibrillation?
Digoxin,
calcium channel blockers,
beta blockers
119
what Complications can occur with atrial fibrillaiton?
embolization; patients need to be put on anticoagulants (Warfarin)
120
how will atrial fibrillation look like in ecg?
**Irregularly Irregular** = no rhythmicity of ventricular rate of depolarization and contraction
121
what wave will be absent during atrial fibrillation in the ecg?
No P waves: replaced by undulating fibrillatory waves [F waves]
122
how will R-R intervals look like in the ecg during atrial fibrillation?
R-R interval is irregular
123
what will be the atrial rate during atrial fibrillation?
Atrial rate: 350-500 bpm
124
what are the coronary arteries?
Left Anterior Descending:
Right Coronary Artery:
Left Circumflex Coronary Artery
125
the left anterior descending will supply what part of the heart?
supplies anterior portion of heart and 2/3 and interventricular septum
126
what is important about left anterior descending artery?
most common artery leading to MI
127
Right Coronary Artery supplies what parts of the heart?
entire posterior and inferior wall of left ventricle; supplies posterior 1/3 of interventricular septum, right ventricle, SA node and AV node.
128
Left Circumflex Coronary Artery supplies what parts of the heart?
supplies the lateral wall of the left ventricle
129
how do you know there is blockage of left coronary artery?
Infarction of entire anterior wall and lateral wall of left ventricle
130
what is Ischemic Heart Diseases?
imbalance between oxygen delivery and oxygen demand
131
what is Angina Pectoris ?
produced by lack of blood flow that produces ischemia ~ chest pain; lasts 15-30 min
132
how is angina pectoris identified?
ECG changes: ST segment depression, T wave inversion
133
what is Myocardial Infarction?
blood supply is completely stopped, myocardial cells in ischemic areas die.
134
what ecg change can be seen during myocardial infarction?
ST segment elevation, pathological Q wave
135
what is the most early treatment for myocardial infarction? and why?
625 mg of Aspirin, for prevention of platelet aggregation
136
what is the treatment for myocardial infarction?
perform angiogram;
single vessel blockage: put a stent in; multiple vessel
blockage: cardiac bypass surgery
137
what symptoms can be seen in myocardial infarction?
dizziness, pain, severe substernal chest pain radiating to jaw, arm, heaviness of chest
138
What patients don’t present with chest pain? why? how is this called?
diabetic pts, silent myocardial infarction because of autonomic neuropathy
139
what is the most common cause of death due to myocardial infarction?
arrhythmias
140
