ECG and Arrhythmias Flashcards
(188 cards)
1
Q
membrane potential across individual cardiac cells consisting of resting membrane potential, depolarization, and depolarization
A
action potential
2
Q
steps of an action potential
A
1) Resting membrane potential
2) Depolarization (Na+ influx)
3) Ca2++ influx and K+ efflux
4) Repolarization (K+ efflux)
3
Q
the electrical field generated by the wave of depolarization or depolarization
changes with time
duration, magnitude, and direction in space
A
cardiac dipole
4
Q
What is the flow of cardiac depolarization
A
1) Sinus Node
2) Atrial Muscle
3) Atrioventricular Node
4) His Bundle
5) Bundle Branches
6) Purkinje Network
7) Ventricular Muscle
5
Q
originates at the SA node and moves as a uniform wave
-right to left
-superior to inferior
A
atrial depolarization
6
Q
originates at the atrioventricular node and moves to His Bundle, Bundle branches, Purkinje Nework, and then the endocardium to the epicardium
-superior to inferior
-right to left)
A
ventricular depolarization
7
Q
what direction does atrial depolarization move
A
superior to inferior
right to left
(uniform wave)
8
Q
what direction does ventricular depolarization move
A
endocardium to epicardium
superior to inferior
right to left
9
Q
what standard position is the animal in for ECG recording
A
right lateral recumbency
-4 limb electrodes and 6 precordial electrodes
10
Q
recording of the amplitude of cardiac dipole versus time
A
electrocardiogram
11
Q
what is the size of the small boxes?
what is size of large boxes
A
1mm
5mm
12
Q
if ECG is recorded at 25mm/sec. How many big boxes is 1 second
A
5 big boxes
13
Q
What wave is atrial depolarization
A
P wave
14
Q
What on the ECG is ventricular depolarization
A
the QRS complex
15
Q
What on the ECG is ventricular repolarization
A
T wave
16
Q
why is there typically a flat line between the P wave and the QRS complex
A
P wave is atrial depolarization and there is typically a little delay at the AV node before ventricular depolarization (QRS complex)
17
Q
What is typically the first negative wave on an ECG (of the QRS)
A
Q wave
18
Q
What is typically the first positive wave of the QRS on ECG
A
R wave
19
Q
What plane are you looking at in an ECG
A
the frontal plane (right and left, and superior and inferior) only the X plane
sternal area
20
Q
What leads measure the frontal plane (right and left with superior and inferior)
A
bipolar limb leads (Leads I, II, III)
21
Q
bipolar limb lead that goes right forelimb (-) to left forelimb (+)
A
lead I
22
Q
bipolar limb lead that goes right forelimb (-) to left hindlimb (+)
A
lead II
23
Q
bipolar limb lead that goes left forelimb (-) to left hindlimb (+)
A
lead III
24
Q
why is it useful to record the ECG with all 3 limb leads
A
each of the limb leads looks at the cardiac wave of depolarization from a different angle in frontal plane
25
you expect lead _____ to have the largest QRS complex
Lead II
26
if you have a QRS complex going in the opposite direction. What is one example of what might be going on
right ventricular hypertrophy
27
How do you get the augmented limb leads (aVR, aVL, aVF)
you take two of the electrodes, average them and put it against the other electrode
gets you 3 more angles
28
What are the different augmented limb leads
aVR: left forelimb and left hindlimb (-) averaged ; right forelimb (+)
aVL: right forelimb and left hindlimb (-) averaged; left forelimb (+)
aVF: right forelimb and left forelimb (-) averaged; left hindlimb (+)
29
left forelimb and left hindlimb (-) averaged ; right forelimb (+)
aVR
30
right forelimb and left hindlimb (-) averaged; left forelimb (+)
aVL
31
right forelimb and left forelimb (-) averaged; left hindlimb (+)
aVF
32
What is the perfect right to left lead that you can use to see if something is traveling right to left
lead I
33
which leads are negative when there is an impulse traveling downwards
aVR and aVL
34
what is the axis lead of normal depolarization
lead II
35
what is the best lead of superior to inferior movement
aVF
36
what is the best lead of right to left movement
lead I
37
Rank the leads by their amplitude of QRS
1) Lead II
2) aVF
3) III
4) I
Negative: aVR and aVL (positive on top)
38
what are the two paperspeeds that ECGs are typically recorded at?
what is the standard voltage calibration
50mm/sec
25mm/sec
10mm/mV
39
which leads give a negative P wave
aVR and aVL
40
which leads give a positive P wave
those that are inferior:
II, III, aVF
lead I can be positive or biphasic
41
How can you tell the P wave is originating at the SA node
Lead I is important
-it is positive or biphasic
the directionality is important to tell where the origin of the P wave is (SA node) or somewhere below the AV node
42
which leads give a positive QRS complex
the inferior leads (II, III, aVF)
43
which leads give a negative QRS complex
aVR and aVL
44
what does the QRS look like on lead I
very variable
but typically positive or isoelectric
45
if the ECG is recorded is at 50mm/sec. How many heavy boxes is 1 sec
10 heavy boxes
46
What is the PQ interval important for telling
First degree heart block
if prolonged: nx dog <40ms; nx cat is <35ms
47
What might a wide p wave tell you
P mitrale
left atrial dilation
48
what might a tall p wave tell you
P pulmonale
right atrial dilation
49
the beginning of the P wave to the first deflection of QRS
important for determining first degree atrioventricular block
P-Q interval
50
A P-Q interval of >40ms in the dog or >35 in cat constitutes
a prolonged P-Q interval indicative of a First Degree Atrioventricular Block
51
What might a really short P-Q interval mean
there pre-excitation (accessory pathway-AP)
congenital defect where muscle extends from atrium to ventricle around AV nodes that excites the ventricle without delay
concerning when it causes a re-entrant circle and causes intense tachycardia
52
How would left ventricular hypertrophy influence ECG
R wave will be tall ( >2.5mV)
not really diagnostic because there are other ways to know their left heart is increased
53
what might a really tall R wave mean (>2.5mV)
there is left ventricular hypertrophy
54
Why is the QRS wider when the rhythm is originating in ventricle
because it is not using the conducting system
55
What does a QRS complex that is narrow mean
it always means that it has supraventricular origin
*normal conduction
56
What does a wide-complex QRS typically mean
>70 ms (dog)
>40ms (cat)
that there is a ventricular origin (it could also be supraventricular)
57
A narrow QRS is always ____________ but it is possible for it to be wide if there us
narrow complex is always supraventricular origin but it is possible to be wide if there is aberrant conduction
58
How might there be a wide-complex QRS that is supraventricular in origin
Left Bundle Branch block makes abnormal conduction and a wide QRS
distinguish from ventricular tachycardia because supraventricular origin has a P-wave
*Ventricular tachycardia does not have a P-wave
59
How do you distinguish supraventricular origin with abnormal conduction (Left Bundle branch block) from ventricular tachycardia
distinguish from ventricular tachycardia because supraventricular origin has a P-wave
*Ventricular tachycardia does not have a P-wave
60
Why might you see dominant S waves in leads I, II, and aVF
-right axis shift
-right ventricular enlargement
61
What are the results of cardiac arrhythmias
1) Cause exercise/activity intolerance (especially in athletes)
2) Syncope
3) Congestive heart failure (tachycardia induced cardiomyopathy)
4) Sudden cardiac arrest
62
What are the diagnostic step approach to cardiac arrhythmias (6 steps)
1) Determine Heart Rate
2) Is QRS narrow or wide
3) R to R interval (regular or irregular)
4) P wave morphology
5) P-QRS relationship
6) Periodicity
63
the heart rate determined on two beats
instantaneous heart rate
1) determine paper speed
2) determine the ms between complexes
3) 60,000/ total ms
64
How many heavy boxes in 3 seconds
at 50mm/sec
at 25mm/sec
50mm/sec: 30 heavy boxes is 3 seconds
25mm/sec: 15 heavy boxes is 3 seconds
65
at 50mm/sec. how many heavy boces in 1 second
10 heavy boxes
66
If paperspeed is 25mm/sec and you count 13 QRS in 15 heavy boxes. What is the heart rate
for 25mm/sec. 15 heavy boxes is 3 seconds
13x20= 260 bpm (tachycardia)
67
How do you determine the instantaneous heart rate
1) Determine paper speed
50mm/s = 20ms/mm
25mm/s = 40ms/mm
2) Determine ms between complexes
3) 60,000/total ms
68
What is normal dog heart rate range
60-160bpm
Tachycardia >160bpm
Bradycardia <60bpm
69
What is normal cat heart rate range
140-220bpm
Tachycardia >220bpm
Bradycardia <140bpm
70
Tachycardia in dog is defined as greater than
160bpm
71
Bradycardia in dog is defined as less than
60bpm
72
Tachycardia in cat is defined as greater than
220bpm
73
Bradycardia in cat is defined as less than
140bpm
74
A narrow QRS is < _____ ms in the dog and tells you that it is __________ origin.
The _________ segment is present and the ____ wave can have any configuration
A narrow QRS is < 70ms in the dog and tells you that it is SUPRAVENTRICULAR origin.
The ST segment is present and the T wave wave can have any configuration
75
A wide QRS is >_________ in the dog and tells you that it is _________ OR ___________. It will have a predominately unidrirectional QRS with a "slurred" _____ segment.
There will be a T wave of ___________
A wide QRS is >70ms in the dog and tells you that it is VENTRICULAR ORIGIN OR ABERRANT CONDUCTION. It will have a predominately unidrirectional QRS with a "slurred" ST segment.
There will be a T wave of opposite polarity
76
What are the criteria for having a wide complex QRS
1) >70ms in dog >40ms in cat
2) mostly unipolar QRS
3) Tall Twave of opposite polarity
4) Slurred ST segment
Causes: Ventricular origin or Supraventricular origin with abnormal conduction (left or right bundle branch block- anatomic) or aberrant conduction (functional block)
77
What are the causes of wide QRS
1) Ventricular origin (Ventricular Ectopic Beats)
2) Supraventricular origin with:
a) abnormal conduction (left or right bundle branch block- anatomic)
b) aberrant conduction (functional block)
78
What is the diagnosis if you have an R to R interval that is irregularly irregular
atrial fibrillation
79
How do you recognize a sinus origin P wave
Positive P wave in lead II
If you see consistent negative P wave in lead II then it probably isnt a sinus origin P wave
80
What would you see if the P wave is originating from the AV node/junctional
negative II, III, and aVF (retrograde P)
81
what do you think when you see a P wave configuration different from the sinus P wave
Is it atrial tachycardia?
82
P wave =
P' wave =
F wave =
f wave =
P wave = SA node origin
P' wave = P wave not originating from SA node a) AV junction origin (retrograde P wave) or b) Atrial origin (different from sinus P wave)
F wave = Atrial flutter (sawtooth pattern)
f wave = atrial fibrillation
83
A P wave of SA node origin
P wave
84
A P wave not originating from SA node
P' wave, can be
a) AV junction origin (retrograde P wave)
b) Atrial origin (different from sinus P wave)
85
a P wave seen in atrial flutter
F wave (sawtooth flutter)
86
A P wave seen in atrial fibrillation
f wave
87
T/F: Atrial fibrillation cannot behave paroxysmally
True
88
Considered normal rhythms
1) Sinus rhythm
2) Sinus arrhythmia
3) Sinus arrhythmia with wandering pacemaker
4) Sinus rhythm with bundle branch block
*All have normal heart rate
89
What are the characteristics of sinus rhythm
1) Normal heart rate
2) Narrow QRS
3) Regular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
90
1) Normal heart rate
2) Narrow QRS
3) Regular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
Sustained Sinus Rhythm
(normal rhythm)
91
1) Normal heart rate
2) Narrow QRS
3) Irregular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
Sustained Sinus arrhythmia (normal rhythm)
-waxing and waning change in heart rate. Vagal response- healthy (associated with a lower heart rate)
92
What are the characteristics of Sinus arrhythmia
1) Normal heart rate
2) Narrow QRS
3) Irregular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
*normal rhythm
-waxing and waning change in heart rate. Vagal response- healthy (associated with a lower heart rate)
93
What are the characteristics of Sinus arrhythmia with wandering pacemaker
1) Normal heart rate
2) Narrow QRS
3) Irregular R-R
4) P and QRS associated
5) Sinus axis P wave is variable
6) Sustained
*Normal rhythm
94
1) Normal heart rate
2) Narrow QRS
3) Irregular R-R
4) P and QRS associated
5) Sinus axis P wave is variable
6) Sustained
Sinus arrhythmia with wandering pacemaker
(normal rhythm)
some variability in P wave configuration is okay in dogs
95
1) Normal heart rate
2) Wide Complex QRS
3) Regular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
Sinus Rhythm with Left Bundle Branch Block
96
What will you see with
Sinus Rhythm with Left Bundle Branch Block
1) Normal heart rate
2) Wide Complex QRS
3) Regular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
97
What breed gets right ventricular-origin ventricular premature complexes (VPC)
Boxers
-Boxer Cardiomyopathy
an arrhythmogenic Right Ventricular Cardiomyopathy
98
Boxer Cardiomyopathy
arrhythmogenic Right Ventricular Cardiomyopathy where there are ventricular premature complexes (VPCs)
serious cardiac condition
99
Premature QRS complexes coming unusually from the right side of the heart
Right ventricular origin ventricular premature complex
-arrhythmogenic right ventricular cardiomyopathy seen in Boxers
100
premature narrow complex ectopic beats that originate in the atrium
atrial premature complexes
101
What distinguishes a ventricular premature beat from an atrial premature beat
Atrial Premature: narrow and comes in early
Ventricular Premature: wide
102
What are characteristics of Atrial Premature Complexes
P' wave different from sinus P wave
Narrow-complex ectopic beats that originate from the atrium
103
How do you tell a left ventricular origin VPC from a right ventricular origin VPC
both will be wide QRS complexes but right VPC will be positive in lead II and the left VPC will be negative in lead II
104
single ectopic beats that occur early (premature) after a normal complex (shortened R-R) generally followed by a wider than normal R-R interval before the next normal complex
Premature Ectopic Complexes.
a) VPC
b) APC
105
APCs originate in the _____ and are ________ complex QRS
VPCs originate in the ______- and are ______ complex QRS
atria (narrow-complex QRS)
ventricles (wide complex QRS)
106
What are the types of tachycardias
1) ventricular tachycardia
2) Atrial fibrillation
3) Sinus tachycardia
4) Supraventricular tachycardias (SVT)
107
What is an abnormal ectopic beat that originates in the ventricles
-only 1 beat
premature ventricular complex (VPC)
108
What is an abnormal ectopic rhythm that originates in the ventricles
-only 2 beats
ventricular couplet
109
What is an abnormal ectopic rhythm that originates in the ventricles
-only 3 beats
ventricular triplet
110
What is an abnormal ectopic rhythm that originates in the ventricles
-4+ beats
-HR: 60-160bpm
accelerated idioventricular rhythm
111
What is an abnormal ectopic rhythm that originates in the ventricles
-4+ beats
-HR >160bpm
Ventricular Tachycardia
112
Monomorphic Ventricular rhythm
ectopic ventricular rhythm only occurring at one place in the ventricle
113
pleopmorphic ventricular rhythm
ectopic ventricular rhythm only occurring at multiple places in the ventricle
114
what makes a ventricular rhythm sustained
if it is >30 seconds
115
paroxysmal
start and stop abruptly
116
What are the characteristics of Monomorphic ventricular tachycardia
1) Fast heart rate
2) Wide Complex QRS
3) Regular R-R
4) Av dissociation (No association with P wave and QRS)
5) Random P waves
6) Sustained
117
1) Fast heart rate
2) Wide Complex QRS
3) Regular R-R
4) Av dissociation (No association with P wave and QRS)
5) Random P waves
6) Sustained
Monomorphic Ventricular Tachycardia
118
What are the characteristics of Pleomorphic (multifocal) ventricular tachycardia
1) Fast heart rate
2) Wide Complex QRS
some are positive and some are negative
3) Regular R-R
4) Av dissociation (No association with P wave and QRS)
5) Random P waves
6) Sustained
119
1) Fast heart rate
2) Wide Complex QRS
some are positive and some are negative
3) Regular R-R
4) Av dissociation (No association with P wave and QRS)
5) Random P waves
6) Sustained
Pleomorphic (multifocal) ventricular tachycardia
120
24 hour ambulatory ECG that helps tell you the arrhythmias occuring over a long time period
holter monitor
121
when ventricular tachycardia gets so fast you cant tell the difference between complexes
monomorphic ventricular origin tachycardia >350bpm
not far from cardiac arrest
ventricular flutter
122
a form of cardiac arrest
disorganized electrical activity in the ventricles
a result of ventricular tachycardia
treat with shock
ventricular fibrillation
123
1) Fast to very fast rate (160-350bpm)
2) always have a wide QRS compatible with ventricular origin
3) R-R interval is typically regular once tachycardia becomes established
4) P wave are disassociated from wide QRS complexes (appear intermittently)
5) can be sustained or show paroxysmal periodicity
6) response to IV lidocainr supports diagnosis
7) can be monomorphic, pleomorphic (multifocal) or polymorphic
ventricular tachycardia
124
What treats ventricular tachycardia
IV bolus of lidocaine
used for diagnosis because it isnt good at treating other forms of tachycardia
125
1) Fast heart rate
2) Narrow complex QRS
3) irregularly irregular R-R
4) P and QRS associated
5) f waves (no P wave)
6) Sustained
Atrial fibrillation
126
What is the pathogenesis of atrial fibrillation
atria has chaotic electrical activity that is bombarding the AV node.
Atria cant generate P wave because requires slow conduction- you get a f wave instead
127
What do you see with atrial fibrillation
1) Fast heart rate
2) Narrow complex QRS
3) irregularly irregular R-R
4) P and QRS associated
5) f waves (no P wave)
6) Sustained
128
1) fast to very fast rate (120-300bpm)
2) typically have narrow QRS compatible with supraventricular origin but can have wide QRS if conduction abnormal
3) irregularly (choatic) irregular R-R interval is hallmark
4) P waves are not present (por possible) fine f waves may be present in baseline
5) Sustained rhythm (paroxysmal atrial fibrillation rarely observed in animals)
Atrial fibrillation
129
1) Fast heart rate
2) Narrow complex QRS
3) Regular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
Sinus Tachycardia
130
What do you see in sinus tachycardia
1) Fast heart rate
2) Narrow complex QRS
3) Regular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
131
What occurs on ECG when the sinus tachycardia is too fast
the P and T waves become superimposed
positive P waves are hidden in the T waves
132
T/F: with sinus tachycardia you see fast heart rates but not very fast
true it is only 160-240 and not extreme
133
1) fast but usually not very fast (160-240)
2) typically have a narrow QRS compatible with supraventricular origin but can be wide QRS if conduction is abnormal
3) P waves are present in front of QRS and compatible with sinus origin (II, III, aVF)
4) If the rate is at upper limit, P waves may be superimposed on previous T waves
5) Does not show paroxysms
6) vagal maneiver may slow but does not terminate tachycardia
Sinus tachycardia
134
T/F: Sinus tachycardia does not show paroxysms
True- they dont stop abruptly but will slow down over time
135
when you massage the carotid sinus or push on the eyeballs
trying to elicit vagal tone
vagal maneuver
136
T/F: Atrial fibrillation does not show paroxysms
True
137
T/F: supraventircular tachycardia does not show paroxysms
false
138
What are the characteristics of Supraventricular Tachycardia
1) Fast heart rate
2) Narrow complex QRS
3) Regular R-R
4) P' wave and position is variable
5) Paroxysmal or Sustained
139
T/F: vagal maneuver may terminate supraventricular tachycardia
true
140
T/F: vagal maneuver may terminate sinus tachycardia
False- it may slow it but it does not terminate the tachycardia
141
The only possible diagnosis if you see a regular sinus rhythm and then immediately go into a tachycardia is:
Supraventricular tachycardia
142
1) Usually fast to very fast (240-300bpm)
2) Narrow QRS compatible with supraventricular origin
3) R-R interval is typically very regular once tachycardia is established
4) P' wave morphology and position is variable depending on mechanism
5) Can be sustained or paroxysmal periodicity
6) Vagal maneuver may terminate
Supraventricular Tachycardia
143
What are the 4 types of SVT
1) Focal Atrial Tachycardia (FAT)
2) Atrial Flutter (Macro-reentrant Atrial Tachycardia) **
3) Atrioventricular Reciprocating Tachycardia (AVRT)
4) Atrioventricular Junctional Tachycardia (AVJT)
144
How does atrial flutter occur
Re-entrant pathway is circulating around the atrium generating F waves (sawtooth pattern)
145
1) Fast heart rate
2) Narrow complex QRS
3) Irregular/Regular R-R
4) F wave (sawtooth)
5) Paroxysmal or Sustained
Atrial Flutter (Marco-Reentrant Atrial Tachycardia)
irregular RR because of coupling to F waves but not chaotically
146
What are the characteristics of Atrial Flutter (Marco-Reentrant Atrial Tachycardia)
1) Fast heart rate
2) Narrow complex QRS
3) Irregular/Regular R-R
4) F wave (sawtooth)
5) Paroxysmal or Sustained
147
if you see a paroxysmal narrow-complex tachycardia, it is likely
supraventricular tachycardia
148
If you have a wide complex rhythm and you arent sure about the cause, what can you do?
Give a bolus of lidocaine
if it goes away it's ventricular tachycardia
if not its a supraventricular rhythm
a) sinus rhythm with LBBB
b) atrial fibrillation with aberrant conduction
c) wide complex tachycardia
149
What are the 4 kinds of bradycardias
1) Sinus bradycardia
2) Sinus Pause (with Junctional Escape)
3) Atrial standstill
4) Atrioventricular block
150
What are the characteristics of sinus bradycardia
1) Slow heart rate
2) Narrow complex QRS
3) Irregular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
151
1) Slow heart rate <60bpm
2) Narrow complex QRS
3) Irregular R-R
4) P and QRS associated
5) Sinus axis P wave
6) Sustained
Sinus bradycardia
152
Why might animal have bradycardia
they are super fit or inappropriate vagal tone (respiratory or GI disease)
drugs (ex: opioids, alpha2 agonists, digoxin, b blockers)
normal in sleeping dogs
vasovagal reflex (cough, urination, vomiting, defecation, emotion)
153
T/F: sinus bradycardia has some degree of sinus arrhythmia
true -vagal mediated
154
1) Sinus origin rhythm with slow heart rate (dog <60bpm, cat <140bpm)
2) often accompanied by sinus arrhythmia and wandering pacemaker
3) Can be physiological, pathological, or pharmacological
a) normal in sleeping dogs, vasovagal reflex (cough, urination, vomiting, defecation, emotion, bradycardia and hypotension > syncope
b) Drugs: alpha-2 agonist, opioids, digoxin, b blockers
Sinus bradycardia
155
A normal sinus rhythm that becomes paused and then resumes with a retrograde P' behind QRS
Sinus pause with junctional escape
156
In Sinus pause with junctional escape once there is junctional escape there is ______
a retrograde P' behind the QRS
157
Where is the retrograde P' after a junctional escape with sinus pause
after the QRS
158
unexpected interruption with SA node activity (2-8seconds)
often terminate with junctional escape beat
Sinus pause
159
What terminates a sinus pause
junctional escape
-retrograde P' wave behind QRS
160
What does a sinus pause mean
there is sinus node dysfunction - intrinsic disease of the sinus node
-frequent sinus pauses with escape beats >3000/day
-tachycardia-bradycardia
161
Sick Sinus Syndrome
condition where the animal is fainting (syncope) due to sinus node dysfunction and experiencing long sinus
Pause >8 seconds
mini schnauzers and other small breed dogs
162
condition where the animal is fainting (syncope) due to sinus node dysfunction and experiencing long sinus
Pause >8 seconds
common in mini schnauzer and other small breed dogs
Sick Sinus syndrome
163
What dog breeds are predisposed to have sick sinus syndrome ( sinus node dysfunction)
miniature Schnauzers and other small breed dogs
164
What is seen in atrial standstill from hyperkalemia
1) Slow heart rate
2) Narrow-complex QRS
3) Irregular RR
4) No P waves
165
What is number one cause of atrial standstill
hyperkalemia
-urinary obstruction?
166
Why might there be no P waves in any lead
Atrial Standstill from hyperkalemia
Atrial Standstill- AV muscular dystropgy
167
What is seen in atrial standstill from AV muscular dystrophy
1) Slow heart rate
2) Narrow-complex QRS
3) Irregular RR
4) No P waves
168
complete absence of P waves in all limb and precordial leads
transient (hyperkalemia) or permanent (AV muscular dystrophy in spring spaniels)
atrial standstill
169
what breed do you get permanent atrial standstill in?
Springer spaniel
170
What is a result of atrioventricular muscular dystrophy seen in springer spaniels
Permanent Atrial Standstill
-complete absence of P waves
171
prolonged PQ interval
dog: >130ms
cat >90ms
first degree AV block
172
What is characteristic of a dog with first degree AV block
prolonged PQ interval
>130ms
173
What is characteristic of a cat with first degree AV block
prolonged PQ interval >90ms
174
intermittent interruption of AV conduction
-All QRS are followed by P waves but some P waves are blocked
Second degree AV block
-mobitz type I (Wenchkebach) or type II
175
intermittent interruption of AV conduction
-All QRS are followed by P waves but some P waves are blocked and there isnt a subsequent QRS
<2:1 are blocked
Second degree AV block
low grade
176
intermittent interruption of AV conduction
-All QRS are followed by P waves but some P waves are blocked and there isnt a subsequent QRS
>2:1 are blocked
Second degree AV block
high grade
177
complete interruption of AV conduction
ventricular escape rhythm with AV dissociation
perkinje fibers are automatic and trigger bradycardia escape
Third Degree AV block
178
What are the characteristics of a Second Degree AV block- Low grade
1) Bradycardia possibly
2) Narrow complex QRS
3) Sinus axis P
4) Intermittent P waves not followed by QRS
5) Every QRS came from a P wave
6) <2:1 P waves not followed by QRS
179
What is the difference from Mobitz I from Mobitz II Second Degree AV block
I: gradual prolongation of PQ prior to block
II: fixed PQ interval prior to the block
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What are the characteristics of a Second Degree AV block- High grade
1) Bradycardia
2) Wide complex QRS
3) Sinus axis P waves
4) Regular R-R
5) AV dissociation not present
6) P waves not followed by QRS >2:1
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What are the characteristics of Third Degree AV block
1) Bradycardia
2) Wide complex QRS
3) Sinus origin P
4) Regular R-R
5) Sustained
6) Complete AV dissociation
7) 160bpm P wave
*No relationship between P waves and ventricles
*ventricular escape rhythm
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How do you treat third degree AV block
pacemaker
183
How do you treat atrial fibrillation
1) rate control - slow AV node conduction (decrease ventricular rate) with diltiazem or +/- digoxin or beta blocker
2) rhythm control/cardioversion- prolong repolarization
with class Ia (quinidine or procainamide) or class III (amiodarone)
DC cardiosynchronous electrical shock
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How do you treat different bradycardia
1) Sinus bradycardia- no treatment
2) sick sinus syndrome- pacemaker
3) High grade 2 or 3 AV block- pacemaker
4) Atrial standstill
temporary- NaHCO3, Ca2++
permanent- pacemaker
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How do you treat a high grade second degree AV block
pacemaker
186
How do you treat acute ventricular tachycardia
lidocaine -IV bolus or CRI
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How do you treat chronic tachycardia (oral)
-sotalol
-mexiletine
atenolol, metoprolol
amiodarone
procainamid
felcanide, proafenone
Mg 2+ torsade de pointe
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