Quiz 1 Flashcards
1
Q
Graphic representation of the heart’s electrical activity.
A
EKG
2
Q
When interpreting an EKG, what should you look at?
A
- Your Patient
- Clinical Correlation
- Comparison with old tracing (if available)
3
Q
How should you approach reading an EKG?
A
Systematically
4
Q
Anatomically, what chamber of the heart dominates the anterior surface?
A
Right Ventricle
5
Q
Electrically, what chamber of the heart dominates?
A
Left Ventricle
6
Q
All cardiac cells have the ability to create action potentials. This is called:
A
Automaticity
7
Q
Cells in the electrical conduction system can:
A
Create Impulses (pacemakers) and/or trasmit impulses
8
Q
What is the main function of the electrical conduction system?
A
Create an electrical impulse and transmit it to the rest of the myocardium.
P.S. This is the electrical energy picked up by an EKG
9
Q
Where does the conduction system occur?
A
Inside the myocardium
10
Q
How are atrial myocytes innervated?
A
Direct Contact from one cell to another
11
Q
What is responsible for transmitting the impulse from the SA node to the AV Node
A
Internodal pathways
12
Q
What is the final component of the conduction system that innervates the ventricular myocytes?
A
Purkinje Fiber System
13
Q
The term for when a pacemaker cell with the highest rate sets the pace for all the subsequent cells?
A
Overdrive Suppression
14
Q
What does overdrive suppression accomplish?
A
Organized beating of all cardiac cells in specialized sequence –> effective pumping action
15
Q
Order of Pacemaker Cells
A
SA Nodes (60-100) Atrial Cells (55-60) AV Node (45-50) Bundle of His (40-45) Bundle Branch (40-45) Purkinje Cells (35-40) Myocardial Cells (30-35)
16
Q
What is the primary pacemaker? It controls the heart beat based on information it receives from the nervous, circulatory and endocrine systems
A
Sinoatrial (SA) Node
17
Q
What is the general bpm for the SA Node
A
60-100 bpm
18
Q
If a heart rhythm originates in the SA Node, what is it called?
A
Sinus Rhythm
19
Q
Where is the SA Node located?
A
The wall of the right atrium at its junction with the SVC
20
Q
Where does the blood supply for the SA node come from? Why is this important?
A
Right Coronary Artery (sometimes left). It’s important because if there is a disruption in blood supply then there needs to be compensation for it – aka another node in function, or an arrhythmia is occurring (SA Node dysfunction)
21
Q
What is the main purpose of the Internodal Pathways?
A
Transmit the pacing impulse from the SA node to the AV node.
22
Q
Where are the internodal pathways located?
A
Walls of the Right atrium and inter-atrial septum
23
Q
What are the three main internodal pathways?
A
Anterior
Middle
Posterior
24
Q
This node is located in the wall of the right atrium next to the opening of the coronary sinus and tricuspid valve. It is responsible for slowing down conduction from atria to ventricles long enough for atrial contraction.
A
AV Node
25
What does the AV node help do (by slowing down conduction from atria to ventricles)?
Maximizes Cardiac Output
26
The AV node is supplied by? (Blood)
Right Coronary Artery
27
Where does the Bundle of His begin?
At the AV node
28
Where is the Bundle of His located?
Partially in the right atrium as well as the interventricular septum
29
What is the only route of electrical communication between the atria and the ventricles?
The Bundle of His
30
Where is the Left Bundle Branch located?
Begins at the Bundle of His and travels through the interventricular septum.
Ends at the beginning of the left anterior and left posterior fascicles (LAF, LPF)
31
What does the Left Bundle Branch innervate?
Left Ventricle and left face of the Interventricular Septum
32
This innervates the anterior and superior left ventricle and terminates in the Purkinje fibers.
Left Anterior Fascicle (LAF)
33
This innervated the inferior and posterior left ventricle and terminates in the Purkinje fibers
Left Posterior Fascicle (LPF)
34
Which Left Fascicle is more easy to block?
LAF because the LPF is fan-like and widely distributed.
35
This starts at the Bundle of His and terminates in the Purkinje fibers. It innervates the Right Ventricle and Right face of the interventricular septum
Right Bundle Branch
36
This is made up of individual cells just beneath the endocardium and directly innervates ventricular myocardial cells.
**It initiates the ventricular depolarization cycle.
Purkinje Fiber System
37
Each cell gives rise to its own electrical impulse. And each impulse varies in the _________ and _______.
Intensity and Direction (Vectors)
38
A vector shows what?
1. Strength of Electrical Impulse
| 2. Direction of Electrical Impulse
39
What is the main purpose of the Internodal Pathways?
Transmit the pacing impulse from the SA node to the AV node.
40
Where are the internodal pathways located?
Walls of the Right atrium and inter-atrial septum
41
What are the three main internodal pathways?
Anterior
Middle
Posterior
42
This node is located in the wall of the right atrium next to the opening of the coronary sinus and tricuspid valve. It is responsible for slowing down conduction from atria to ventricles long enough for atrial contraction.
AV Node
43
What does the AV node help do (by slowing down conduction from atria to ventricles)?
Maximizes Cardiac Output
44
The AV node is supplied by? (Blood)
Right Coronary Artery
45
Where does the Bundle of His begin?
At the AV node
46
Where is the Bundle of His located?
Partially in the right atrium as well as the interventricular septum
47
What is the only route of electrical communication between the atria and the ventricles?
The Bundle of His
48
Where is the Left Bundle Branch located?
Begins at the Bundle of His and travels through the interventricular septum.
Ends at the beginning of the left anterior and left posterior fascicles (LAF, LPF)
49
What does the Left Bundle Branch innervate?
Left Ventricle and left face of the Interventricular Septum
50
This innervates the anterior and superior left ventricle and terminates in the Purkinje fibers.
Left Anterior Fascicle (LAF)
51
This innervated the inferior and posterior left ventricle and terminates in the Purkinje fibers
Left Posterior Fascicle (LPF)
52
Which Left Fascicle is more easy to block?
LAF because the LPF is fan-like and widely distributed.
53
This starts at the Bundle of His and terminates in the Purkinje fibers. It innervates the Right Ventricle and Right face of the interventricular septum
Right Bundle Branch
54
This is made up of individual cells just beneath the endocardium and directly innervates ventricular myocardial cells.
**It initiates the ventricular depolarization cycle.
Purkinje Fiber System
55
Each cell gives rise to its own electrical impulse. And each impulse varies in the _________ and _______.
Intensity and Direction (Vectors)
56
A vector shows what?
1. Strength of Electrical Impulse
| 2. Direction of Electrical Impulse
57
If vectors are going in the same direction, then they are ?
Additive
58
If vectors are going in opposite directions, then they ?
Cancel each other out
59
Sum of all heart vectors is called the ______ and should be going from (direction)...
Electrical Axis; Superior Right to Inferior Left
60
What are the points of the leads/electrodes positioning?
1. Multiple pictures of the heart
2. 3D perspective
3. Info where pathology is occurring
61
What is an important thing to note about limb leads? And what are the 4 limb leads?
Limb leads need to be placed at least 10 cm away from the heart.
```
Right Arm (RA)
Left Arm (LA)
Right Leg (RL)
Left Leg (LL)
```
62
The rest of the leads are called precordial leads. How are these labeled?
V1-6
63
Where are V1 and V2 located?
Either side of the sternum at the 4th intercostal space
64
Where are V3, V4, V5, and V6 located?
```
V3 = Following the electrical axis down and left
V4 = Down and left on Mid Clavicular Line
V5 = Down and left on the Anterior Axillary Line
V6 = Down and left on Mid Axillary Line
```
65
Positive impulses move away from the electrode, cause a ______ wave.
Downward
66
Positive impulses move toward from the electrode, cause a ______ wave.
Upward
67
Positive impulses perpendicular to the electrode, cause a ______ wave.
Biphasic (Ups and Downs #StepByStep)
68
Standard Limb Leads =
I - RA to LA
II - RA to LL
III - LA to LL
69
Augmented Limb Leads =
aVR (from right shoulder)
aVL (from left shoulder)
aVF (from feet)
70
How far apart are the lease from each other? (Angle)
30 degrees
71
Precordial leads are on a plane that is __________ t the limb leads.
Perpendicular. This is a Transverse Plane
72
Limb Leads are on a cut of the heart through the center. What type of plane is this?
Coronal/Frontal
73
Combining Frontal and Transverse, which leads face the bottom of the heart? (Inferior Wall)
II, III and the aVF
74
Combining Frontal and Transverse, which leads face the anterior of the heart? (Anterior Wall)
V3 and V4
75
Combining Frontal and Transverse, which leads face the lateral part of the heart? (Lateral Wall)
I, aVL, V5, and V6
76
Combining Frontal and Transverse, which leads face the septum of the heart? (Septal Wall)
V1 and V2
77
EKG paper: Each little box = ? seconds
1/25 sec or 0.04 sec
78
EKG Paper: One big box (has 5 little) = ? seconds
0.2 secs
79
Each lead is measured for how long?
3 second
80
If looking at rhythm which lead would you look at?
Lead II
81
Looking vertically at the EKG paper, what are we looking at? How much does 1 little box represent?
Voltage; 1 mm aka 0.1 mV
82
Where is the calibration box located and what does the standard box show?
Right of EKG and it is commonly 10 mm high (1 V) and 0.2 sec wide.
83
What does it mean by temporal spacing?
Three leads represented at one. The complexes touch the vertical straight edge is actually occurring at the same time. So if the p wave is visible in one, follow it to the other leads and that is still representative of the lead.
84
This is the part of the EKG that shows the electrical events of the heart followed by the mechanical event. These can be single, isolated positive or negative deflections, or biphasic defelections
Waves
85
This is the part of the EKG that shows the portion of complex between waves
Segment
86
This is the part of the EKG that shows the distance in time between two cardiac events.
Interval
87
This wave represents electrical depolarization of both atria. Should be upright in lead II (SUPER IMPORTANT) and inverted in aVR.
Normal width =
The P wave
88
This part of an EKG is between the end of the P wave and the beginning of the QRS. It represents the time for stimulus to travel through the AV node and conducting tissue up until ventricular depolarization. It is usually isoelectric.
The PR Segment
89
The PR segment is usually _______ if the patient has pericarditis
Depressed
90
What's the different between the PR segment and PR Interval?
PR Interval is the P wave AND the PR segment. It also measures the impulse in the SA node until Ventricular Depol.
91
Normal PR Interval =
0.12 - 0.2 second
92
This represents the Ventricular Depolarization and should be measures in several leads including the precordial leads. Should be < 0.12 sec
QRS Complex
93
This is the first negative deflection after the P wave.
Q
94
This is the first negative deflection after the R wave.
S
95
This is the first positive deflection after the P wave.
R
96
Large Q waves represent?
Prior Infarct
97
This forms from the end of the QRS until T wave. It is electrically neutral between ventricular depolarization and repolarization (systole).
ST Segment
98
What is the J point?
Where QTS ends and ST begins.
99
This represents ventricular repolarization and is the next deflection after the ST segment. Could be up or down depending on pathology or complex (should be the same orientation as the QRS).
T wave
100
Where should the T wave be measured? What is the normal? What happens if it is taller than expected?
Precordial Leads; Normal = 2/3 R wave; Tall = Hyperkalemia
101
This represents the ventricular depol to repol. It varies greatly, but is normally less than half of the RR interval.
QT Interval
102
A prolonged QT interval is indicative of?
Torsades de Pointes
103
WTH is the QTc Interval?
QT interval corrected for heart rate.
104
As the heart rate ______, the QT interval shortens.
Increases
105
QTc = QT + 1.75(ventricular rate - 60)
Commonly calculated by the EKG machine... but I wanted to freak Amanda out...if she makes it this far.
106
U waves are rare and oddly associated with what?
Hypokalemia
107
RR Intervals are important in what?
Regular vs. Irregular Rhythm
108
PP intervals are important in?
Heart block and atrial flutter
109
AHIAHI
```
Rate
Rhythm
Intervals
Axis
Hypertrophy
Infarct
```
*Systematic Approach*
110
How is rate generally measured?
RR Interval (QRS complexes)
111
Normal or Tachycardic Rates are measured as
Every Big Line after the Q peak is 300, then 150, then 100, then 75, 60, 50.
112
Normal or Tachycardic Rates are measured as
complexes in 6 seconds x 10 = bpm
