Basics: Waves, Complexes, Intervals, And Heart Rate (Lauren) Flashcards
1
Q
One small box is ___mV and ____seconds
A
.1 mV
0.04 seconds
2
Q
One large box is ____mV and ____seconds
A
- 5 mV
0. 2 seconds
3
Q
What is an isoelectric line?
A
Flat line (no electrical activity is occurring)
4
Q
What is the normal length of a P wave
A
0.06-0.10 seconds (1.5-2.5 boxes)
5
Q
What is the normal appearance of a P wave?
A
Upright and rounded
6
Q
What is the normal height of a P wave?
A
0.5-2.5 mm
7
Q
The PR interval begins and ends where
A
Start of the P eave to beginning of QRS complex
8
Q
What is the normal length of a PR interval?
A
0.12-0.2 seconds (3-5 boxes)
9
Q
Where does the PR segment begin and end?
A
It is the flat line between the the end of the P wave and the start of the QRS complex
(Not the same thing as PR Interval)
10
Q
What is the normal length of the QRS complex?
A
.06 to 0.12 seconds (1.5-3 boxes)
11
Q
What is the ST segment?
A
The flat line that follows the QRS complex
12
Q
What is the J-point?
A
The point where the QRS complex meets the ST segment
13
Q
Where does the QT interval begin and end?
A
Start of QRS complex to end of T wave
14
Q
What is the normal length of the QT interval?
A
0.36-0.44 seconds (9-11 boxes)
15
Q
As the heart rate slows, the QT interval ______
A
Increases
16
Q
How big is the calibration mark that ensures the ECG machine is properly calibrated?
A
10 small squares high
17
Q
What is this:
“Markings on ECG that are not a product of the heart’s activity. May be caused by patient movement”
A
Artifact
18
Q
Lead I is between which two electrodes?
A
RA negative
LA positive
19
Q
Lead II is between which two electrodes?
A
RA negative
LL positive
20
Q
Lead III is between which 2 electrodes?
A
LA negative
LL positive
21
Q
What is meant by “augmented” limb leads in aVR, aVL, and aVF?
A
They are augmented/enhanced by the ECG machine because the waveforms produced by these leads are normally very small
22
Q
Which electrode does aVR use?
A
RA positive
23
Q
Which electrode does aVL use?
A
LA positive
24
Q
Which electrode does aVF use?
A
LL positive
25
What does aVR view?
Base of heart (atria and great vessels)
26
What does aVL view?
Lateral wall of LV
27
What does aVF view?
Inferior wall of LV
28
Where do you place V1?
4th ICS on right of sternum
29
Where do you place V2?
4th ICS on left of sternum
30
Where do you place V3?
Halfway between V2 and V4
31
Where do you place V4?
5th ICS in mid clavicular line
32
Where do you place V5?
Anterior axillary line, same horizontal plane as V4
33
Where do you place V6?
mid axillary line, same horizontal plane as V4
34
The Precordial/chest leads give you what views of the heart?
Anterior and lateral views in a horizontal plane
35
What are modified chest leads?
Leads the are used for patient monitoring in ED, telemetry and ICU. Uses 3 electrodes.
36
Which electrodes are used in modified chest leads (MCL)and where are they placed?
There are two options:
MCL1: Right arm (RA), Left arm (LA) and LL placed where you would normally put V1
MCL6: Right arm (RA), Left arm (LA), and LL placed where you would normally place V6
37
Which leads would you look at to view the anterior surface of the heart?
V1-V4
38
Which leads would you look at to view the lateral surgfaces of the heart?
I, aVL, V5-V6
39
Which leads would you look at to view the inferior surface of the heart?
II, III, aVF
40
What is the 5 step process for analyzing ECG tracings?
1. Determine regularity
2. Calculate rate
3. Evaluate P waves
4. Evaluate QRS complexes
5. Evaluate PR intervals
41
How do you determine if the heart rate is regular?
Make sure that the distance of the R-R intervals is the same as the P-P intervals
(Atria and ventricles are contracting at the same rate)
42
What are the 3 methods for determining regularity?
1. Caliper method
2. Paper and pen
3. Counting the small squares
43
What is it called when the pacemaker changes location from site to site, producing a slightly irregular rhythm?
Wandering atrial pacemaker
44
What is it called when the heart rate suddenly accelerates, producing an irregularity in the rhythm?
Paroxysmal tachycardia
45
What is it called when a rhythm irregularity repeats itself in a cyclin fashion?
Patterned irregularity
| Ex: rate increases during inspiration and decreases during expiration
46
What is the classic condition that causes an irregularly irregular rhythm
Atrial fibrillation
47
What are the 4 methods for calculating heart rate?
6 second interval x 10
Large box estimate (300, 150, 100, 75, 60, 50 method)
1500 method
Rate calculator
48
How do you estimate heart rate using the 6 second interval x 10 method?
Count the number of QRS complexes in a 6 second portion of ECG and multiply by 10
(Quick and easy, but not as accurate)
49
How do you calculate heart rate using the large-box estimate method?
Find an R wave located on or near a bold line.
Count down along each bold line until the next consecutive R wave
The bold lines represent heart rates of 300, 150, 100, 75, 60, and 50
The bold line it falls on represents the Heart Rate
50
When is the large-box estimate method less accurate for calculating HR?
Irregular rhythms
51
What is the most accurate method to calculating HR?
1500 method
52
When can you NOT use the 1500 method to calculate HR?
Irregular rhythms
53
How do you calculate HR using the 1500 method?
Count the number of small boxes between 2 R waves and divide 1500 by that number
54
Heart rate less than ____ bpm is bradycardia
60
55
Heart rate greater than _____ bpm is tachycardia
100
56
When might you see “Tall Rounded” or “Tall Peaked” P waves?
Increased right atrial pressure
Right atrial dilation
57
A P wave amplitude over 2.5 mm suggests_______
Right atrial enlargement aka “P pulmonale”
58
What can cause wide, notched, or biphasic P waves?
Increased left atrial pressure
Left atrium dilation
59
A P wave longer than 0.10 seconds (2.5 boxes) suggests ________
Left atrial enlargement aka “P mitrale”
60
Biphasic P waves are normal in which lead?
V1
61
What causes P waves that look different from sinus P waves?
Impulses that arise from the atria, but NOT the SA node:
Premature atrial complexes (PACs)
Wandering atrial pacemaker
Atrial tachycardia
62
What can cause the P wave to be buried in the T wave of the preceding beat?
Rapid rates (atrial tachycardia)
when this happens, the T waves are often peaked, notched, or larger than normal.
63
What do flutter waves look like?
“Saw toothed” pattern
64
What causes flutter waves/ F waves?
Atria fire rapidly at rate of 250-350 bpm aka atrial flutter
65
What do Fibrillatory waves look like?
Absence of discernible P waves, and instead you just get a chaotic looking baseline preceding the QRS complexes
66
What causes Fibrillatory waves?
Atria firing rapidly from ~many~ sites at a rate >350 bpm
aka a fib
67
What causes inverted P waves?
Retrograde depolarization of the atria. Caused when a P wave originates from the:
lower Right atrium near AV node
Left atrium
AV junction
(May immediately precede, occur during, or follow the QRS complex)
68
Inverted P waves are associated with dysrhythmias that originate from the ______
AV junction
69
What would it mean if you had more P waves than QRS complexes?
Impulse was initiated in the SA node or atria, but was blocked and didn’t make it to the ventricles
70
Does a QRS complex always have on Q wave, one R wave, and one S wave
No there can be a missing Q or R wave (QS complex or RS complex)
Can be more than one R or S wave
71
What would we call a second R or S wave?
R’ or S’
| R-prime or S-prime
72
What would we call a small R or S wave?
r wave or s wave (lowercase)
73
What will the QRS complex look like if there was a dysrhythmia that originated from above the ventricles?
Normal
74
What can cause tall QRS complexes?
Ventricular hypertrophy
Abnormal pacemaker
Aberrantly conducted beat
75
What can cause low-voltage QRS complexes?
Obese patient
Pericardial effusion
Hypothyroidism
76
What can cause wide-bizarre QRS complexes of supraventricular origin?
Intraventricular conduction defect, usually a R or L BBB
77
What causes aberrant conduction?
An electrical impulse reaches the bundle branch while it is still refractory after a previous impulse
(Impulse travels down unaffected bundle branch first, followed by the other)
78
Will the QRS complex be wider or narrower in aberrant conduction?
Wider
79
What part of the ECG represents the depolarization of the heart from the SA node through the atria, AV node, and His-Purkinje system?
PR interval
80
What causes short PR intervals?
Impulse originated in the atria close to or in the AV junction
Travels through abnormal accessory pathways to the ventricles, leading to premature ventricular depolarization called pre-excitation
81
What causes longer PR intervals?
Occurs when there is a delay in impulse conduction through the AV node.
For example: 1st Degree AV heart block
82
What can cause varying PR intervals?
Wandering atrial pacemaker
2nd-Degree AV Heart Block type I
83
What happens to the PR intervals in 2nd Degree AV heart block, type I?
PR intervals get longer and longer until a QRS complex is dropped and the cycle repeats
84
What causes PR intervals to be absent ?
Atrial flutter
Atrial fibrillation
3rd degree AV heart block
85
Why is there no PR interval in 3rd degree heart block?
Atria and ventricles are beating independently of each other
