Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

VET433: Cardio/Respiratory > ECGs & Arrhythmias > Flashcards

ECGs & Arrhythmias Flashcards

1
Q

what is the resting membrane potential of cardiomyocytes

A

-90 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

steps of cardiac action potential

A

SA node sends impulse –> Na+ entry –> cardiomyocyte depolarization –> Ca influx –> cardiac muscle contraction –> K+ efflux out –> repolarization –> cardiac muscle relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the path of electrical activity in the heart

A
  1. SA node
  2. internodal conduction tracts –> R atrium –> L atrium
  3. AV node
  4. bundle of his
  5. purkinje fibers
  6. cardiomyocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

SA node

A

sinoatrial node

FASTEST pacemaker
located in the RA wall
spreads current RAPIDLY to through the internodal tracts to reach the AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

superior exit from atrium

A

high in atrial wall
common exit taken by the current with high sympathetic tone (tall P wave)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

inferior exit in atrium

A

low in atrial wall
common exit taken by the current with high parasympathetic tone (shorter P wave)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

wandering pacemaker

A

variable P wave height due to variable exit pathways based on autonomic input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

AV node

A

atrioventricular node

SLOW pacemaker
located in the septum between RA/RV near the center of the heart

gatekeeper - the ONLY conduction pathway between the atria and the ventricles

current spreads slowly through the AV node to allow for atrial depolarization and contraction to finish before sending signal to the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

bundle of his

A

conducts current RAPIDLY to the ventricles via the L and R bundle branches

allows for coordinated contraction across the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

purkinje fibers

A

penetrating fibers that conduct signal through the ventricles to the myocytes

once current reaches myocytes –> cell to cell signaling occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how is an ECG generated

A

heart is activated by a depolarizing current that moves as a boundary between resting and activated tissues

electrical field gets generated onto the body surface –> detected by ECG surface electrodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

TP interval

A

time in between depolarizations

time during which the SA node initiates conduction PRIOR to the P wave

(not strong enough to be detected on ECG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

P wave

A

atrial depolarization

SA node –> R atrium –> L atrium
- slight delay between R and L atrial depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

PQ interval

A

conduction from SA node –> AV node –> bundle of his

represents the time required to travel through the AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

QRS wave

A

ventricular depolarization

3 vectors in species with category A conduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

ST interval

A

early ventricular repolarization

duration of ventricular contraction - Ca coming into cells but no electrical activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

T wave

A

ventricular repolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

QT interval

A

entire time for ventricular depolarization and repolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what leads are bipolar

A

leads I, II, III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what leads are unipolar

A

aVR
aVL
aVF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the correct positioning for the animal when taking an ECG

A

right lateral recumbency

can be standing or sternal if only looking at rate and rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are indications for running an ECG

A
  • clinical signs - weakness, collapse, syncope
  • auscultation - abnormal heart rate or rhythm
  • diagnosis of heart disease or a systemic disease that causes arrhythmias
  • monitoring of critically ill patients/anesthesia
23
Q

what are the steps to evaluating an ECG

A
  1. heart rate
  2. heart rhythm
  3. P wave for every QRS
  4. QRS for every P wave
  5. complex morphology
24
Q

how to calculate average HR if paper speed is 25 mm/s

A

number of beats per 30 big boxes x 10

25
Q

how to calculate average HR if the paper speed is 50 mm/s

A

number of beats per 30 big boxes x 20

26
Q

how to calculate instantaneous HR if the paper speed is 25 mm/s

A

1500 / number of small boxes in the R-R interval

27
Q

how to calculate instantaneous HR if the paper speed is 50 mm/s

A

3000 / number of small boxes in the R-R interval

28
Q

what are the supraventricular rhythms

A

APCs
atrial fibrillation
supraventricular tachycardia

29
Q

what are the ventricular arrhythmias

A

VPCs
ventricular tachycardia
ventricular escape beats
ventricular fibrillation

30
Q

what are the conduction disturbance arrhythmias

A

AV blocks
bundle branch blocks

31
Q

what causes sinus arrhythmia

A

high resting vagal tone

normal in dogs
abnormal for cats in the clinic (normal at home)

faster during inspiration
slower during expiration

32
Q

sick sinus syndrome (SSS)

A

sinus node dysfunction causing sinus arrest AND clinical signs of collapse/syncope

(must have both clinical signs and ECG findings)

33
Q

sinus arrest

A

period of >2 seconds or >2 P-P intervals without sinus node function

often followed by a ventricular escape beat

34
Q

supraventricular arrhythmias

A

irregular heartbeats that originate above the ventricles

35
Q

atrial premature complexes (APCs)

A

abnormal early depolarization of the atria that gets normally conducted to the ventricles

  • NARROW QRS that comes before the next sinus beat is expected
  • can often hide the T wave of the previous beat
36
Q

supraventricular tachycardia

A

tachycardia caused by rapid signaling from above the ventricles

  • tachycardia
    (dogs > 160-180; cats > 260)
  • regular rhythm
  • P waves are present but can be difficult to find due to tachycardia
37
Q

atrial fibrillation

A

areas of the atria continuously depolarizing/repolarizing and bombarding the AV node over and over again

AV node can help slow down rhythm but patient is still tachycardic

  • irregular R-R interval
  • NO P waves
  • tachycardia
  • variable R amplitude
  • narrow QRS complex
  • irregular rhythm
  • undulating baseline
38
Q

ventricular arrhythmias

A

abnormal heart rhythms that occur due to irregular ventricular beats

complexes are WIDE and BIZARRE looking
do not have a P wave initiating the complex

39
Q

ventricular premature complexes (VPCs)

A

ventricles depolarize before the atria (comes in early)

  • wide QRS coming in where a sinus beat should be
40
Q

ventricular escape beat

A

SA node fails to fire so the slow AV node takes over (comes in late)

bradycardia
- dogs: 40-60
- cats: 100-140

  • wide QRS complexes coming in after a prolonged TP interval
41
Q

accelerated idioventricular rhythm

A

rhythm in which ventricular ectopic beats exceed the rate of SA node firing (take over)

dogs: 60-160 bpm
cats: within 10% of sinus

42
Q

ventricular fibrillation

A

disorganized ventricular rhythm due to random depolarization of areas of the ventricles

unable to have a coordinated contraction

  • short, wide QRS complexes
  • disorganized, varying heights
43
Q

ventricular tachycardia

A

rapid heart rate generated from the ventricles

  • wide QRS complexes
  • regular rhythm
  • lack of P wave association
  • tachycardia
    (dogs < 160; cats > 220)

can be paraoxysmal, sustained, monomorphic, or polymorphic

44
Q

hyperkalemia (sinoventricular rhythm)

A

high potassium –> increases resting membrane potential –> harder to depolarize the atria before the ventricles

impulse is still generated in the SA node, but it reaches the AV node and ventricles before the atria can depolarize

  • tall, tented T wave
  • NO P waves
  • bradycardia
  • wide QRS
45
Q

AV block

A

delayed or absent conduction through the AV node

  • long PQ interval
  • P waves without QRS
46
Q

first degree AV block

A

prolonged PQ interval but ALL P waves are conducted

caused by high vagal tone
tx with atropine

47
Q

second degree AV block

A

some P waves are conducted, some are not

low grade: roughly every other P wave is conducted

high grade: more than every other P wave is blocked

48
Q

second degree mobitz type I AV block

A

PQ interval gradually prolongs until one P wave is blocked

caused by high vagal tone
tx with atropine

(normal in horses)

49
Q

second degree mobitz type II AV block

A

consistent PQ interval but P waves are randomly blocked

caused secondary to heart disease
NOT responsive to atropine

50
Q

third degree AV block

A

no P waves are conducted
QRS is entirely dissociated from P waves

  • no consistent PQ interval
  • SA node consistently fires at its own rhythm
  • AV node fires junctional escape beats randomly throughout

caused by AV node disease
tx with pacemaker

51
Q

P pulmonale

A

tall P wave

cause: RA enlargement

52
Q

P mitrale

A

wide P wave

cause: LA enlargement

53
Q

tall R wave

A

LV enlargement

54
Q

R cranial deviation

A

RV enlargement

VET433: Cardio/Respiratory (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions