Basic EKG interpretation - Exam 1 Flashcards
1
Q
What are the two types of cardiac cells?
A
Pacemaker
Contractile
2
Q
What is automaticity? What type of cell does this?
A
the heart’s innate ability to generate its own spontaneous action potentials without any external stimuli
Pacemaker cells
3
Q
Another name for cardiac muscle cells
A
Cardiac myocytes
4
Q
The ____ cells create the electrical pathway of the heart, as known as:
A
Pacemaker
Conduction system
5
Q
As the action potential travels through the conduction system and myocardium, it will lead to:
A
atrial and ventricular depolarization and contraction
6
Q
The rate at which the pacemaker cells fire is:
A
heart rate
7
Q
The pacemaker cells are located within:
A
the SA node, AV node, bundle of His, right and left bundle branches, and Purkinje fibers
8
Q
What % of the myocardium is contractile cells?
A
99%
9
Q
What type of channels cause cell-to-cell conduction?
A
Sodium
10
Q
Release of _____ to interior myocytes causes contraction
A
Calcium
11
Q
_____ ion outflow causes repolarization
A
Potassium
12
Q
What lacks in a-fib d/t the lack of atrial kick?
A
Preload
13
Q
Ineffective squeeze leads to bad what?
A
Cardiac output
14
Q
One of the biggest reasons we cancel OR cases is because of what?
A
Electrolyte abnormalities
15
Q
What electrolyte is involved in the clotting cascade?
A
Calcium
16
Q
What 3 things cause cells to burst and release potassium?
A
Crush injuries
Massive tissue trauma
Amputation
17
Q
SA node info:
A
Automaticity
Primary pacemaker
ANS/hormones modify timing/strength
PNS dominant
18
Q
What is the normal HR of the SA node?
A
60-100 bpm
19
Q
Where is the SA node located?
A
the back of the right atrium near the superior vena cava entry
20
Q
The conduction system of the heart can be influenced by:
A
the sympathetic nervous system to speed up the heart rate by activating cardiac beta receptors
21
Q
What can facilitate slowing of the heart rate?
A
Parasympathetic nervous system
22
Q
Atrial depolarization is represented by what wave on the EKG?
A
P wave
23
Q
What meds can we give to block parasympathetic system?
A
Atropine
Glycopyrrolate
24
Q
What is another name for the interatrial pathway?
What does the internodal pathway consist of?
A
Bachman’s bundle
Internodal (Anterior, middle, posterior)
25
Bachman's bundle facilities depolarization from the right atrium to:
Left atrium
26
AV node info:
Inherent pacemaker
Delays conduction 0.1 second
End part of PR interval
27
Where is the AV node located?
the base of the right atrium near the interventricular septum
28
Key difference in SA and AV node
the pacemaker cells within the AV node generate their action potentials at a slower rate than the SA node
29
If the SA node were eliminated or stopped functioning properly:
it would be up to the AV node to spontaneously depolarize the heart.
30
Bundle of His has how many branches?
2
31
Where is the bundle of his?
Interventricular septum
32
The bundle of his has pacemaker cells that can generate action potentials at how many beats per min?
40-60
33
Where does the action potential travel after the bundle of his?
Right and left bundle branches
34
The bundle branches consist of pacemaker cells that can generate spontaneous action potentials at what rate?
20-40 bpm
35
If an action potential originates in the ventricle, what is this called?
Idioventricular rhythm
36
Where does the action potential travel after the bundle branches?
Purkinje fibers
37
As the action potential travels through the bundle of His, the bundle branches, and the Purkinje fibers, the ventricular contractile myocytes depolarize and contract.
This is called:
Systole
38
Ventricular depolarization is represented by what on EKG?
QRS complex
39
Purkinje fibers can generate spontaneous action potentials at what rate?
20-40 bpm
40
If a heart rate is less than 20, this is known as an:
Agonal rhythm
41
If you had a wide QRS with a HR of 10-20, this probably originated where?
Purkinje fibers
42
Normal rate of AV node:
40-60 bpm
43
Where does the rhythm generate in a 2nd degree heart block?
Ventricles
44
What do the boxes represent on normal EKG paper?
6 second strip
Big box: 0.2 seconds
Little box: 0.04 seconds
45
Duration of a normal P wave:
<0.12 seconds
46
If a P wave is longer than it's normal time, this is what rhythm?
First degree heart block
47
P wave will be upright in what leads?
I
II
aVF
V4-V6
48
PR interval represents:
AV conduction
49
Duration of PR interval:
0.10-0.20
50
Why is the later part of the PR interval flat?
Due to the delay as it travels through AV node
51
Duration of QRS complex:
<0.12 seconds
52
ST segment represents:
Early stages of ventricular repolarization
53
When is elevation/depression significant?
>1 mm
54
What can an elevated T wave indicate?
Hyperkalemia
55
What can an elevated ST segment indicate?
Ischemia
56
What does the T wave represent?
Ventricular repolarization
57
T waves are positive in what leads?
I
II
V3-V6
58
Things that delay repolarization:
Electrolyte abnormalities
Myocardial injury
59
Why can't you see atrial repolarization?
Where is it masked?
It occurs during ventricular depolarization
QRS
60
Inherent pacemakers of the heart:
SA node
AV node
Ventricular tissue
61
What is this rhythm?
Sinus rhythm
62
When looking at strips, what do we need to be looking at?
- Look at heart rate then rhythm: is it regular?
- Is there a P wave with every QRS?
- Do you have a fixed PR interval?
- Look at QRS: is it wide?
- Look for any funny beats ... are they appropriate shape? Extra beats? PVCs, PACs?
- Is R-R interval fixed?
63
What is this rhythm? Describe?
Sinus bradycardia
- HR 40
- P wave: not perfectly rounded; conduction problem in SA node
- PR normal
- QRS normal
- P with every QRS
- Fixed R-R interval
64
What is this rhythm? Describe?
Sinus tachycardia
- P wave appears smaller than normal ; not as round; but uniform
- Heart rate - 140
- P for every qrs
- Pr interval and r-r fixed
- Qrs normal
65
What is the range for sinus tachycardia?
100-150
66
If the HR is over 150, we consider what type of rhythms?
Supraventricular rhythms
67
What is the rhythm? Describe?
Junctional
- Heart rate 50 - gives clue to origin, probably not following SA node
- P wave is inverted/ retrograde - its travelling away from natural conduction pathway
- Pr interval fixed
- Qrs fixed
- R-r fixed
- No strange beats
- This is junctional because of inverted/retrograde p wave
68
If a junctional rhythm is below 40, it's called:
Junctional bradycardia
69
Normal junctional rate:
40-60
70
What is this rhythm? Describe?
Junctional tachycardia
- P wave is weird little notch looking thing before QRS
- P waves not consistent shape
- Pr interval hard to calculate
- Heart rate: 80 (This is faster than normal junctional rhythm ,so this is junctional tachycardia)
71
If you don't see P waves in a junctional rhythm, consider:
A-fb
72
What is the rhythm? Describe?
SVT
- P wave - may or may not see
- Rhythm regular
- With SVT, common to not be able to see origin; but this is okay
73
What is the difference in SVT and PSVT?
PSVT starts and stops (paroxysmal)
SVT stops but we do not see it start again
74
If you have a narrow QRS in SVT, where does it originate?
Atria
75
If you have a wide QRS in SVT, where does it originate?
Ventricles
76
What is this rhythm? Describe?
Premature atrial contraction
- HR 70
- PR interval fixed
- QRS normal width but not fixed R-R interval
- When you compare the amplitude of some of the QRS, you can see some of the QRS have reduced amplitude
77
If you have a heart beat that occurs too early, you may not have ______ or ________
Total filling
Complete repolarization
78
PACS are not really a problem, but what can be?
PVCs
79
What is this rhythm? Describe?
A-fib
- Rate: 150-300 for above
- Cant calculate PR
- QRs narrow
80
A-flutter has a HR below:
150
81
Meds we can use to treat a fib:
Amio: K+ channel blocker, delays repolarization
Cardiazem: CCB, causes delay
82
What rhythm is this? Describe?
Atrial flutter
- HR 70
- P wave with every qrs; have extra p waves
- Pr-interval not fixed
- Qrs slightly wide but within normal parameter
- “Sawtooth” pattern in atrial flutter
- Varying conductions ex. 2:1, 3:1, and even 7:1
83
What is something that can cause a flutter?
Caffeine/stimulants
84
What is this rhythm? Describe?
PVCs
- PR interval fixed
- P wave nice and round
- QRS within normal limits
- P with every QRS
- Then we have weird beats.. (Its wide QRS - so it came from ventricles; Takes a while for repolarization afterwards)
85
What does multifocal mean?
Multiple cells are causing it
86
PVCs are dangerous when there is:
Ventricular irritability
87
What could be causes of PVCs?
Electrolyte abnormalities
Lack of oxygen
Ischemia
88
To treat PVCs, we need to treat:
Underlying cause
89
What can we use to treat runs or Tach or frequent PVCs?
Lidocaine or amio
90
What is the rhythm? Describe?
1st degree AVB
- Normal p wave
- Fixed p-r interval
- When you count, you can see it has passed the 0.2 threshold - so wide/prolonged p-r interval
- Clinically insignificant
91
What is this rhythm? Describe?
2nd degree, type I
- Underlying HR: 50
- P wave upright
- P waves look identical - so atrial okay
- As you move through the strip, you notice pr interval is getting longer and longer due to delayed conduction
- At the end you don't conduct a beat at all
92
What is this rhythm? Describe?
2nd degree, type II
- P-r interval is fixed in second degree!
- Heart rate 50
- P wave uniform and upright
- For some reason, the conduction does not make it to the ventricle – so lack of ventricular conduction; can be 1:1, 2:1, etc.
93
What is the difference in 2nd degree type I and type II?
Generally, type 1 is not symptomatic, but once at type 2, then we need to intervene
94
In a heart block, what drug will the heart not respond to?
Atropine
95
What is this rhythm? Describe?
3rd degree AVB
- HR 30
- All p waves are similar
- Pr interval are not the same
- QRS complex is wide and varied
- Atria and ventricles are not communicated
96
What is it called when the atria and ventricles are not talking to each other?
Atrioventricular dissociation
97
Dyssynchrony in a 3rd degree AVB can cause:
Decreased CO
98
What is this rhythm? Describe?
V-tach
- HR 182
- Wide QRS
- No identifiable atrial activity b/c its masked
- Regular rhythm
- All ventricular impulses look the same - so one mad cell sending this impulse
- Patients can be stable in vtach!!
99
What is this rhythm? Describe?
V fib
- Ventricular rhythm coming from multiple different cells/foci
- Cells are doing whatever they want
- Polymorphic - spreading cell to cell around the ventricle - causing very amplitudes
- Wide and fast ; HR 247
100
Volatile agents can cause:
Sensitivity to the myocardium
101
Meds we give that decrease HR that are not specifically targeted to decrease heart rate:
Pain meds
Precedex
Neo– should cause reflex bradycardia
102
Sevo can cause:
bradycardia in infants
103
What is the oculocardiac reflex?
a physiological response that causes a decrease in heart rate (bradycardia) when pressure is applied to the eyeball or traction is exerted on the extraocular muscles
104
What volatile prolongs QT interval?
Desflurane
105
Zofran can cause:
QT prolongation (risk of torsades)
106
Large amounts of anesthetic can cause:
Bradycardia
107
Norepi reuptake inhibitors:
Cocaine
Ketamine
108
Hyperkalemia causes:
Succs
Blood
109
What is another consideration when giving blood?
Blood also has citrate which is going to chelate calcium.. So your calcium is going to decrease
110
Hemodynamic disturbances during endotracheal intubation:
- If do not adequate put them to sleep, the stimulation will cause heart rate to go up; can also see vagal stimulation causing bradycardia – this is due to stimulation from laryngoscope
- Bradycardia can also be caused in kids due to hypoxia – kids become bradycardic before hypoxic
111
If you are working on carotids, this can cause:
How do you treat it?
Bradycardia
Infiltrate area with lido
112
If working on thyroid, you may see:
Decreased HR
113
If you are filling the abdomen with CO2, you are decreasing ____ due to ____
Venous return
Increased pressure
114
Direct stimulation of what organs can cause bradycardia?
Abdominal organs
Vagina
Cervix
115
If you are placing swan/central line, you can see PVCs due to what? What can this cause?
"Tickling" the ventricle with the wire
Prolonged ventricular arrythmia
116
Surgical manipulation of cardiac structures can cause:
Arrhythmias
117
Eyes surgeries may stimulate:
Oculocardiac reflex
118
119
Hypoxemia can cause:
Tachycardia
In kids, they can become bradycardic in later stages of hypoxemia
120
Cardiac ischemia can happen in OR because:
Everything we give in OR can decrease CO
121
Ketamine increases _____ and __________
HR
Oxygen demand of heart
122
Catecholamine excess can cause:
Elevated HR
123
How would excessive intravascular lidocaine be treated?
Lipid rescue
124
What two adverse events can occur from local anesthetic injection into the vasculature?
Severe bradycardia
Asystole
125
What anatomic structure (discussed in class) causes dysrhythmias when stimulated during cardiac surgeries?
Pulmonary arteries
