Mod 3 - EKG Analysis & Interpretation Flashcards
1
Q
what is the most precise method to use to calculate heart rate
A
1500 method
2
Q
what are the 3 ways to find heart rate from ekg
A
1500, sequence, and 6-second
3
Q
how do you find the ventricular rate using the 1500 method
A
1500 divided by # of small boxes between R waves
4
Q
how do you find the atrial rate using the 1500 method
A
1500 divided by # of small boxes between p waves
5
Q
aka sequence method
A
300 method or R-R method
6
Q
how do you use the sequence method
A
300 divided by # of large boxes between R waves
7
Q
how do you use the 6 second method
A
number of QRS complexes in 6 seconds x 10
8
Q
what do the hashmarks at the top of an ekg strip signify
A
3 second intervals
9
Q
how do you calculate maximum heart rate
A
220 - pt age
10
Q
how do you calculate target heart rate
A
(220 - pt age) x percent of maximum
11
Q
what is the range for percent of maximum
A
60-85%
12
Q
the QRS complex represents
A
ventricular depolarization
13
Q
irregular intervals in Q waves can signify
A
ventricular dysfunction
14
Q
which is the best method to find heartrate when it is fast or irregular
A
1500
15
Q
what is the best method to calculate heart rate when it is slow
A
300
16
Q
what is not visible but happens during ventricular depolarization
A
atrial repolarization
17
Q
where does the QRS complex end
A
J point
18
Q
QRS complexes normally range from
A
0.04-0.1 seconds
19
Q
define J POINT
A
exact point in time where ventricular depolarization stops and ventricular repolarization starts
20
Q
how can the j point be represented in an ekg during myocardial ischemia
A
elevate or depress below baseline
21
Q
what does the T wave represent
A
ventricular repolarization
22
Q
what does the U wave represent even if it is not always visible
A
repolarization of bundle of His and Purkinje fibers
23
Q
the normal PR interval range is
A
0.12-0.2 seconds
24
Q
what does the P-P interval represent
A
amount of time between atrial depolarization cycles
25
what does the R-R interval represent
amount of time between ventricular depolarization cycles
26
what does the QT interval represent
1 complete ventricular cycle (ventricular depolarization and repolarization)
27
how is the QT interval measured
beginning of Q wave to end of T wave
28
where is the PR interval located
beginning of P wave and ends at beginning of Q wave
29
what does the PR segment represent
end of atrial contraction and beginning of ventricular contraction
30
where is the PR segment located
end of P wave to beginning of Q wave
31
what does the ST segment represent
early phase of ventricular repolarization (end of ventricular depolarization to beginning of ventricular repolarization)
32
where is the ST segment
end of S wave to beginning of T wave
33
P wave and PR interval abnormalities indicate
atrial dysfunction
34
QRS and T wave abnormalities can demonstrate
ventricular dysfunction
35
how should T waves be shaped and oriented
peak toward end of wave and deflected in same direction as QRS complex
36
how does low potassium levels impact heart function
decreased heart rate
37
how does high potassium levels impact heart function
abnormal rate or rhythm
38
low concentrations of calcium can cause
slowed heart rate
39
high concentrations of calcium will cause
longer than normal contractions
40
what are the signs of normal sinus rhythm
- p wave present, upright, and rounded
- p wave has amplitude less than 2.5 mm
- p wave duration less than 110 milliseconds
- QRS complex usually narrow
41
sinus bradycardia can be normal in these pts
- athletes
- pt's with hypothyroidism
- older adults with sedentary lifestyle
42
tachycardia is expected under these conditions
- during exercise
- with pt's who have hyperthyroidism
43
define SINUS DYSRHYTHMIA
slight irregularity in rhythm
44
sinus dysrhythmia is most likely associated with
normal breathing patterns
45
sinus arrest is not significant unless it is longer than
6 seconds
46
what is the cause of sinus arrest
failure of SA node to fire
47
define ATRIAL FLUTTER
atria contract faster than ventricles
48
define ATRIAL FIBRILLATION
atria quivering without organized contraction
49
where do junctional arrhythmias occur
at AV node/tissue
50
how do junctional arrhythmias appear in an ekg and why
inverted P wave because the electrical activity flows backwards
51
why does the AV node initiate the impulse
when SA node damaged
52
describe PREMATURE JUNCTIONAL COMPLEXES
early impulse that occurs before next expected beat and P wave occurs before/after/buried in QRS complex
53
how does the P wave appear in a junctional escape rhythm
inverted if not absent
54
what is happening during a junctional escape rhythm
atria and ventricle receive impulse simultaneously bc the AV node is acting as a back-up pacemaker
55
what are some characteristics of a junctional escape rhythm
- heart rate maximum of 60/min
- signs of reduced cardiac output
56
define ATRIAL KICK
excitement of atria with rise in internal pressure to forcefully push blood into ventricles
57
define ACCELERATED JUNCTIONAL RHYTHM
same as escape rhythm but at a rate of 60-100 bpm
58
what are the characteristics of accelerated junctional rhythm
- inverted if not absent p wave
- ventricular rate 60-100 bpm
- generally no signs of decreased cardiac output
59
define JUNCTIONAL TACHYCARDIA RHYTHM
same as escape and accelerated rhythm but heart rate 100-150 bpm
60
what is the characteristics of junctional tachycardia rhythm
- 100-150 bpm
- inverted if not absent p wave
- sx of palpitations or fluttering
61
aka supraventricular tachycardia
narrow complex tachycardia
62
what are characteristics of supraventricular tachycardia
- pulse greater than 150/min
- p waves not usually visible
- appear as a hump directly into QRS complex ("hopping motion")
63
list sinus arrythmias
- sinus bradycardia
- sinus tachycardia
- sinus dysrhythmia
- sinus arrest
64
list atrial arrythmias
- atrial flutter
- atrial fibrillation
65
list junctional arrhythmias
- premature junctional complex
- junctional escape rhythm
- accelerated junctional rhythm
- junctional tachycardia rhythm
66
define PREMATURE VENTRICULAR COMPLEX
ventricles contract out of normal sequence initiated by ectopic focal point within ventricles
67
what are characteristics of a PVCs
- p wave not visible
= QRS complex often wider than normal and unusual shape
- palpitations/fluttering in throat/chest
68
severity related to PVCs depend on
frequency and reduction in cardiac output
69
what are the requirements for an occasional PVCs
1-5 in 1 minute
70
what are the requirements for frequent PVCs
at least 6 per minute
71
what is a unifocal PVC
single early PVC indicating one irritable area
72
aka PVC
premature ventricular complex
73
define a multifocal PVC
PVCs with multiple shapes indicating more than 1 irritable area
74
define a interpolated PVC
PVC with no interruption in normal rhythm
75
define bigeminy PVC
PVC occur every second beat
76
define trigeminy PVC
occur every third beat
77
define Quadgeminy PVC
occur every fourth beat
78
define coupling pvc
two pvcs occur back to back
79
list ventricular arrhythmias
- premature ventricular complex
- v tach
- v fib
- idioventricular rhythm
- agonal rhythm
80
define ventricular tachycardia
at least three PVCs in a row with ventricular rate greater than 100/min
81
what are characteristics of v tach
- no noticeable p waves
- QRS wide and unusual
- t wave deflected in opposite directions
- few sx
- ekg appears mountanous
82
what are characteristics of idioventricular rhythm
- ventricular rate 20-40 bpm
- no discernible p waves
- QRS complex wide and unusual
83
if ekg presents as idioventricular rhythm but has a pulse of 40-100 bpm, then the pt has
accelerated idioventricular rhythm
84
what are the 3 pacemakers of the heart
SA node, AV node, and Purkinje fibers
85
when does idioventricular rhythm occur
only ventricular pacemaker is functioning
86
when does agonal rhythm occur
when all 3 pacemakers fail
87
what are characteristics of agonal rythm
- wide, unusual QRS complex
- no P or T wave
- ventricular rate less than 20/min
88
what is the difference in QRS shape of agonal rhythm and idioventricular rhythm
idioventricular rhythm looks like lumps and agonal rhythm has somewhat distinguishable QRS complex
89
define HEART BLOCK
block in electrical conduction pathway causing delayed/absent ventricular depolarization
90
when does a bundle branch block occur
interference somewhere in the bundle branches
91
describe a left bundle branch block (LBBB)
instead of current going down left bundle branch it goes down septum to ventricle causing abnormal right to left stimulation
92
describe a right bundle branch block (RBBB)
left ventricle sends impulses through myocardium to right ventricle to depolarize right ventricle (septum is depolarized normally)
93
define a first-degree atrioventricular block
delay in conduction from SA node to AV node
94
how does a first-degree atrioventricular block appear
PR interval greater than normal 0.2 seconds
95
aka second-degree atrioventricular block type I
Mobitz I or Wenckebach
96
how do 2nd degree AV block type I appear
PR interval progressively longer until QRS missing and pattern repeats
97
what happens during a 2nd-degree AV block type I
non-conducted/blocked impulses from AV node to ventricles
98
aka 2nd degree atrioventricular block type II
Mobitz II
99
what are characteristics of a Mobitz II
- PR interval constant
- P wave present with no QRS complex or T wave
100
what happens during a Mobitz II
AV node selectively blocked specific impulses
101
aka third-degree atrioventricular block
complete heart block
102
what happens during a complete heart block
all electrical impulses originating above ventricles blocked causing ventricles and atria to contract independently
103
how does a complete heart lock appear
- no pattern to cardiac cycle
- atria contract at normal rate but ventricles contract at 20-40 bpm
104
sx of Vfib
dizziness, feeling of impending doom, chest discomfort, SOB, seizure activity
105
sx ventricular tachycardia
- drops in blood pressure and level of consciousness
- deterioration into pulseless rhythm/VFib
- dizziness
- feeling of impending doom
- chest discomfort
- SOB
106
what is the response for Vtach
call code, initiate CPR and AED
107
what are common causes of asystole
- large pulmonary embolism
- large myocardial infarction
- respiratory arrest (hypoxia)
- overdose
- hypothermia
- acidosis
- electrolyte abnormalities
- tension pneumothorax
- trauma
108
t/f: pts with 3rd degree AV block do not progress to cardiac arest
false
109
define PACING SPIKE
artifact in tracing from artificial pacemaker
110
how does a pacing spike appear as
thin spike at P wave, QRS, or both
111
how does a pacing spike appear if atrial pacing is used
normal p wave followed by single thin line
112
how does the pacing spike appear if ventricular pacing is used
QRS looks like a bundle branch block with a spike before QRS complex
113
which two sets of leads are contiguous with each other
- leads II, III, AVF
- V1, V2, V3
114
what does it mean for leads to be contiguous
look at the same part of the heart
115
how does myocardial ischemia appear on ekg
- ST segment depression of 1 mm or greater in two contiguous leads
- T wave inversion
116
ST elevation is the main indicator of a
ST elevation myocardial infarction (STEMI)
117
what does a STEMI mean
complete blockage of coronary artery and tissue has not died yet
118
what do pathologic Q wave changes in two or more continuous leads indicate
infarction and necrosis
119
how do pathologic q wave changes appear
Q wave measures 0.04 sec and will be equal/greater than 1/3 height of R wave
120
you are doing a 12 lead on an 8 year old, where do the leads go
V1, 2, 4, 5, 6 in normal spots but V3 on the right side left diagonal to V3 similar to V4
121
