Reading EKGs Flashcards
1
Q
What is a segment on an EKG?
A
Horizontal flat line that connect 2 or more waveforms
2
Q
What is an interval on an EKG?
A
Include one segment and one or more waveforms
2
Q
What are the 2 segments on an EKG?
A
PR segment
ST segment
3
Q
What is the PR interval composed of?
A
Entire P wave
PR segment
4
Q
What are the 5 intervals on an EKG?
A
PR interval
ST interval
QRS interval/complex
QT interval
RR interval
5
Q
What does the PR interval represent?
A
Atrial depolarization
Conduction delay through AV node
6
Q
What does the PR segment represent?
A
Conduction delay through the AV node
7
Q
What is the ST interval composed of?
A
ST segment
T wave
8
Q
What is the QRS interval composed of?
A
Q wave
R wave
S wave
9
Q
What is the R-R interval?
A
Everything that comes between 2 R wave peaks
10
Q
What is the j-point?
A
The junction between the end of the QRS complex and the beginning of the ST segment
11
Q
Where should the ST segment be evaluated?
A
1 box past the J point
12
Q
What is the QT interval composed of?
A
From just after the PR segment to just after the T-wave
13
Q
What is on the y axis of an EKG?
A
Voltage
14
Q
What does the QT interval represent?
A
Ventricular depolarization
Ventricular repolarization
15
Q
What is on the x axis of an EKG?
A
Time
16
Q
What are the methods to counting heart rate on an EKG?
A
300 method
1500 method
17
Q
Describe the 300 method for counting heart rate on an EKG
A
300 divided by the number of large boxes between 2 R waves
18
Q
Describe the 1500 method for counting HR on an EKG
A
1500 divided by the number of small boxes between 2 R waves
19
Q
Describe the 6 second method for counting HR on an EKG
A
The number of P waves in 6 seconds multiplied by 10
20
Q
How much time do the large boxes measure on an EKG?
A
0.2 seconds
21
Q
How much time do the small boxes measure on an EKG?
A
0.04 seconds
22
Q
How much voltage do the small boxes on an EKG represent?
A
0.1 mV
22
Q
How much voltage do the large boxes on an EKG represent?
A
0.5 mV
23
What does the PR interval tell us?
Indicates AV conduction time
Represents the time from the SA node firing to the end of AV node delay
24
What is the normal time for a PR interval?
0.12-0.20 seconds
3-5 small boxes
25
What can cause the timing of the PR interval to change?
Elevated HR
Age
Pathological process
26
Where is the PR interval measured from?
The beginning of the P wave to the beginning of the QRS complex
27
What is indicated by a PR interval of greater that 0.2 seconds?
1st degree heart block
Aka 1st degree AV block
28
What is a normal time interval for the QRS complex/interval?
0.06-0.12 seconds
1.5-3 small boxes
29
Where is represented by the QRS complex?
Ventricular depolarization
30
What does the QRS complex “hide”?
Atrial repolarization
31
What could a widened QRS complex indicate?
Left ventricular enlargement
Ectopic foci
Electrical conduction block in the bundle branches
32
What is the standard time for a R-R interval?
0.6-1.2 seconds
3-6 large boxes
33
What is the normal time interval for the QT interval?
0.4-0.44 seconds
34
Where is the QT interval measured from?
The end of the PR segment to the end of the T wave
35
When is the QT interval considered prolonged?
When the QT interval extends beyond midpoint of R-R interval
36
What can cause a long QT interval?
Side effect of various medications
Metabolic abnormalities
Electrolyte imbalances (low levels of potassium)
Long QT syndrome
37
What is the risk associated with Long QT syndrome?
The delay in repolarization may result in another electrical stimulus occurring before the ventricles have repolarized resulting in depolarization before repolarization is complete
38
Describe long QT syndrome
Congenital or acquired heart condition where there is delayed repolarization of the ventricles
39
What can Long QT syndrome cause?
Dangerous dysrhythmias
Tosades de points (type of ventricular tachycardia)
40
What does the ST segment represent?
The interval between depolarization and rapid repolarization of the ventricles
The plateau phase of repolarization, very slow at the beginning of repolarization of the ventricles
41
Describe an ST elevation
Defined as the ST segment occurring above the baseline
42
What can cause an ST elevation?
Myocardial infarction
Myocardial ischemia
43
What is the acronym for ST elevation?
STEMI
ST Elevation, Myocardial Infarction
44
Describe ST depression
Defined as the ST segment occurring below the baseline
45
What do ST depressions caused by myocardial ischemia look like?
Characterized by a horizontal or down sloping ST segment
46
What can cause an ST depression?
Myocardial ischemia
47
What is the acronym for ST segment depression?
NSTEMI
Non ST Elevation MI
48
What are common causes of ST elevation
MI
Myocardial ischemia
Coronary vasospasm
Pericarditis
LBBB
LV hypertrophy
Ventricular aneurysm
49
What are common causes of ST depression
MI
Myocardial ischemia
Digoxin effect
Ventricular hypertrophy
PE
LBBB
Drugs
Metabolic conditions (hypokalemia)
Misc conditions
50
What is deflection on an EKG?
The deflection of a wave is the direction in which it records the electrical activity on the EKG
51
When does a wave have positive deflection?
When it is moving upward
52
When does a wave have a negative deflection?
When it is moving downward
53
What is voltage on an EKG measured in?
Millivolts
54
What is voltage generally expressed as on an EKG?
Amplitude
55
Describe amplitude in regards to an EKG
Measures how far and in what direction a waveform differs from the isoelectric baseline
56
T/F: Amplitudes are always a positive number
False. Can be either positive or negative
57
T/F: magnitudes can be either positive or negative
False. Magnitudes can only be positive
58
On an EKG, magnitude is typically expressed in _______
Millimeters
59
On an EKG, amplitude is expressed as ____
Millivolts
60
Describe a normal sinus rhythm
Electrical impulse initiated by SA node
Will have P wave, QRS complex and T wave
Rate of 60-100
60
Chest pain
SOB
Dizziness
Anxiety
61
Describe sinus tachycardia
Rhythm appears with all normal waves but at an accelerated rate
Greater than 100 bpm
62
Describe sinus bradycardia
Rhythm appears with all normal waves but at a depressed rate
Less than 60 bpm
63
What can cause a sinus bradycardia?
Vagal maneuver/valsalva maneuver
Medications
MI
SA node dysfunction
Increased ICP
Hypothermia
Hypokalemia
64
Describe ventricular fibrillation
A life threatening cardiac dysrhythmia in which coordinated contraction of the ventricular myocardium is replaced by chaotic and disorganized release of multiple electrical impulses from ectopic foci
65
What is the main cause of ventricular fibrillation
Hypoxia
66
Why is ventricular fibrillation so dangerous?
The fibrillation compromises the ventricles ability to effectively pump blood
66
What are the two types of ventricular fibrillation patterns?
Fine and coarse
67
What is indicated by a fine ventricular fibrillation pattern
Fine ventricular fibrillation is indicative of the back end of cardiac arrest approaching asystole
67
What does ventricular fibrillation look like on an EKG?
Saw teeth
Erratic, no patterns or regular deflections
68
What is indicated by a coarse ventricular fibrillation pattern
Coarse ventricular fibrillation is indicative of the front end of cardiac arrest
69
How does hypoxia cause ventricular fibrillation
Hypoxia causes hyperirritability of the cardiac muscle tissue prompting the release of electrical stimuli from ectopic foci
70
What are ectopic foci?
Abnormal myocytes that act as pacemakers and display automaticity with the myocardium by releasing electrical stimuli causing premature uncoordinated polarization and contraction
71
What is asystole?
An absence of electrical activity in the myocardium
72
Describe sinus dysrhythmia
Changing intervals from one cardiac complex to the next
Resembles normal sinus rhythm
73
Who is sinus dysrhythmia considered to be normal in?
Young healthy individuals
Athletes
74
What is the cause of sinus dysrhythmia in healthy individuals?
Changing pressures on the heart as they inhale and exhale
75
Define fibrillation
A rapid twitching of muscle fibers of the heart that is caused by an abnormal discharge of electrical nerve impulses
76
Define morphology in regards to EKGs
The size shape and waveforms on an EKG
77
Define monomorphic
Having but a single form or structure
78
Define polymorphic
Having two or more clearly different morphs, forms or structural patterns
78
What normally keeps ectopic foci or automaticity foci from causing ventricular fibrillation ?
They are normally overridden by the higher rate of the SA or AV node
78
What does a premature ventricular contraction look like on an EKG?
Increased width and amplitude
Not preceded by a P wave
> .10 seconds
79
Describe premature ventricular contraction
A sudden and irregular contraction of the ventricles due to ectopic foci
79
What causes a premature ventricular contraction?
Irritated ectopic foci, generally responding to hypoxia
Hypokalemia
Long QT syndrome
79
What can the shape of a PVC wave tell us?
The location of the ectopic foci
80
When can a PVC cause a ventricular tachycardia or ventricular fibrillation?
When the PVC occurs in the vulnerable period when myocytes have not been completely repolarized it can result in VT or VF
81
What is occurring if you see a bigeminy pattern? Trigeminy? Quadgeminy?
Bigeminy = PVC every other beat
Trigeminy -= PVC every 3 beats
Quadgeminy = PVC every 4 beats
82
When 2 PVCs occur one after the other, what is it called?
A couplet
83
What is it called when you have 3 PVCs or more in a row?
Ventricular tachycardia
84
Describe ventricular tachycardia
Characterized by a large QRS complex > 0.12 seconds
Originates from ventricles
>100 bpm
85
What are the two clinical types of V-tach?
Stable
Unstable
86
When is V-tach considered sustained?
When it lasts more than 30 seconds or is symptomatic
87
When is V-tach considered unsustained?
When it lasts <30 seconds AND is asymptomatic
88
Describe monomorphic V-tach
Every single QRS complex looks exactly the same
Coming from the same ectopic foci
89
Describe polymorphic V-tach
Each QRS complex varies in magnitude and duration indicating multiple ectopic foci
90
Describe torsades de pointes
Cyclic progressive increase in magnitude followed by progressive decrease in magnitude of waves
Very life threatening
91
Describe stable V-tach
Hemodynamics are WNL
HR, RR, SAP
Patient presents “normal”
92
What are the clinical interventions for stable V-tach?
Vagal maneuver
Start IV
Obtain 12 lead EKG
Cardiology consult
93
Describe unstable V-tach
Hypotensive
Altered mental state, potentially unresponsive
SOB
Chest pain
94
What are the clinical interventions for unstable V-tach?
Attempt valsalva maneuver if patient can follow commands
Immediate cardioversion
95
How might a patient in unstable V-tach present?
Pale or cyanotic
Diaphoretic
Weak
Dizzy
96
Describe atrial fibrillation
Atria quiver due to ectopic foci
Chaotic asynchronous electrical activity
No P waves
97
What does A-fib look like on an EKG?
No discernable P or T wave
Erratic disorganized tracing without any type of tracing regularity or deflections or identifiable waves between QRS complexes
98
Describe how atrial flutter looks on an EKG
A sawtooth pattern between QRS complexes
99
What is the difference between A-fib and A-flutter
A-fib has multiple ectopic foci
A-flutter has a singular ectopic foci
100
Which types of heart block are typically asymptomatic?
1st degree heart block
2nd degree Type 1 (wenckebach)
101
Which types of heart blocks are potentially life threatening?
2 degree type 2 (mobitz)
3rd degree AV block aka complete heart block
102
A first degree heart block is characterized by what?
A prolonged PR interval
> 0.2 seconds or 1 big box
103
Describe 2nd degree heart blocks
2nd degree heart blocks allow some atrial depolarization (P waves) to conduct electrical stimuli to the ventricles producing a QRS response, while some atrial depolarizations are blocked leaving lone P waves without an associated QRS response
104
What is happening during a second degree heart block?
PR interval is increasing due to a delay of AV node conduction of the electrical impulse
AV node does not depolarize completely or adequately by the time the next impulse arrives
105
What can cause a second degree heart block?
AV nodal ischemia during an inferior wall MI
AV blocking drugs
Increased vagal tone
106
Describe the PR interval in a 2nd degree type 1 heart block
PR interval is not constant, becomes increasingly longer until QRS complex is skipped entirely
107
Is treatment typically needed for second degree type 1 heart block?
no
108
What is the difference in the PR interval when comparing type 1 and type 2 second degree heart blocks?
Type 1 = PR interval grows longer until QRS complex is absent
Type 2 = PR interval is constant
109
What is happening in a second degree type 2 heart block?
A blockage is occuring in the electrical conduction system at the bundle of His or bundle branches
110
What happens if a 2nd degree type 2 heart block isnt treated?
Will progress to a 3rd degree heart block
111
What are other terms for 2nds degree type 2 heart block?
Mobitz
Hay
112
What is another term for a 3rd degree heart block?
Complete heart block
113
What is happening in 3rd degree heart block?
Atria and ventricles have rates that are independent of each other
114
Describe the P-P interval and R-R interval in 3rd degree heart block
Both are constant
P wave may be hidden, but it is regular
115
Describe the atrial and ventricular rate in 3rd degree heart block
Completely independent of one another
Atrial rate is normal
Ventricular rate is typically slow
116
What does a bundle branch block indicate?
A conduction block somewhere in the ventricles
116
Describe the PR interval in 3rd degree heart block
Absent
117
How are bundle branch blocks diagnosed?
By recognizing a wide QRS complex
118
How are bundle branch blocks differentiated?
By determining where they originate from
119
What is the main cause of atrial flutter?
coronary artery disease
120
What is a complication associated with atrial fibrillation?
Increased risk of blood clots
