Brainscape's Knowledge GenomeTM

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


See full index

Small Animal Medicine II > Sinus Arrhythmias > Flashcards

Sinus Arrhythmias Flashcards

1
Q

What is an arrhythmia?

A

abnormality in the rate, regularity, or site of origin of the cardiac impulse

  • normal sequence of activation of the atria and ventricles is altered
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 possible origins of arrhythmic beats?

A
  1. atrial: positive deflection of P waves with constant PR interval and normal QRS duration
  2. junctional: negative deflection of P waves or no P waves with a normally conducted short QRS (unless BBB)
  3. ventricular: no P waves, wide/bizarre QRS that can be negative or positive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 major deviations for normal rate of automaticity?

A
  1. too fast = tachycardia
  2. too slow = bradycardia
  3. too irritable = premature
  4. absent = block
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the expected rate of automaticity of the SA node/atrial conduction tissue, AV junction/His bundle, and bundle branches/Purkinje fibers?

A

70-160 bpm

40-60 bpm

20-40 bpm

(whatever site fires fastest will drive the HR)

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

What allows ideal interpretation of ECGs?

A

right lateral recumbency with proper leads

  • read lead II!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are 4 possible artifacts that may look like arrhythmias on ECGs?

A
  1. 60 cycle electrical interference
  2. shivering or motion
  3. panting
  4. petting or tapping head
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is likely happening on this ECG?

A

panting artifact

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

What is likely happening on this ECG?

A

electrical interference

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

What is likely happening on this ECG?

A

breathing artifact

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

What is likely happening on this ECG?

A

purring artifact

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

What are the 5 general steps to reviewing ECGs?

A
  1. calculate HR
  2. assess rhythm - do all complexes look the same, are intervals regular?
  3. identify P waves - are they positive, in normal shape and location?
  4. assess QRS shape and duration
  5. assess relationship between P and QRS complexes - should be one P for every QRS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Reviewing ECGs:

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

What to evaluate on an ECG:

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

What is normal sinus rhythm?

A

beat initiated by the SA node, resulting in normal rhythm, and an upright P wave

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

What are 4 ECG features of sinus rhythm?

A
  1. regular rhythm
  2. very similar RR intervals
  3. positive P waves on lead II
  4. P-QRS complexes normal with constant PR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is occurring in this ECG?

A

normal sinus rhythm

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

What is sinus arrhythmia?

A

an irregular heartbeat originating from an irregular rate in the SA node, commonly associated with respiration due to vagal tone

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

How does sinus arrhythmia appear on ECGs? In what 3 patients is this most commonly seen?

A
  • HR increases with inspiration
  • HR decreases with expiration
  • there is a normal P with every QRS, but PP and RR intervals vary (regularly irregular)
  1. dogs that are fit
  2. brachycephalics
  3. patients with respiratory disease
19
Q

Is treatment necessary for sinus arrhythmias?

A

NO —> helps rule out lung disease over cardiac disease (more likely lung disease if this is present)

  • Atropine can reverse it, but it is not commonly necessary
20
Q

What is occurring in these ECGs?

A

sinus arrhythmia

  • HR increases with inspiration
  • HR decreases with expiration
21
Q

What is occurring in this ECG?

A

sinus arrhythmia

  • HR increases with inspiration
  • HR decreases with expiration
22
Q

What is a wandering atrial pacemaker?

A

mixed sinus and atrial rhythm —> P waves come from outside the SA node, but still within the atria, resulting in different shapes of the P waves closer to the QRS complex

  • high vagal tone is common, so it is often seen with sinus arrhythmia
23
Q

What are the 2 major signs of wandering atrial pacemakers on ECG? Is treatment necessary?

A
  1. variable morphology/amplitude of P waves (negative = junctional)
  2. variable PR interval (often decreased)

NO —> typically no hemodynamic consequences

24
Q

What is occurring in this ECG?

A

wandering atrial pacemaker

  • abnormal P wave morphology
  • rest of waves are normal
25
Q

What is sinus bradycardia? How do they compare in dogs and cats?

A

very slow and infrequent complexes, but normal PQRST

  • DOGS = < 70 bpm; can be normal in larger breeds (no treatment necessary)
  • CATS = < 120 bpm; NEVER normal in cats
26
Q

What are some physiological causes of sinus bradycardia in dogs and cats?

A

ELEVATED VAGAL TONE

  • vomiting
  • intubation
  • increased CNS pressure
  • ocular disease, increased IOP
  • hypothermia
  • hypothyroidism
  • good conditioning
  • respiratory disease
27
Q

What are some pathological causes of sinus bradycardia in dogs and cats?

A
  • systemic disease with toxicity (renal failure)
  • impending cardiac arrest
  • CNS disease
  • HYPERKALEMIA
28
Q

What are some drugs that can cause sinus bradycardia in dogs and cats?

A
  • phenothiazines
  • propanolol
  • morphine
  • anesthetics
  • calcium channel blockers
29
Q

What is occurring in this ECG?

A

sinus bradycardia

30
Q

What are some clinical signs of sinus bradycardia?

A

weakness, lethargy, collapse

  • treatment only necessary if clinical
31
Q

What is occurring in this ECG?

A

sinus bradycardia

32
Q

What arrhythmia is commonly associated with sinus bradycardia? Why? How is it differentiated from a VPC?

A

ventricular escape beats

ventricular pacemakers take over to create a beat since there was no P wave

it is not premature

33
Q

What is occurring in this ECG?

A

ventricular escape beat

  • wide/bizarre QRS complex
34
Q

When are escape beats seen? What is seen on ECG?

A

decreased heartbeat (sinus bradycardia, AV block) where the heart will rescue itself by having another pacemaker take over, either from the AV node, junction, or ventricles

seen following a pause longer than the normal sinus cycle length (RR interval)

35
Q

What is the difference between a junctional and ventricular escape?

A

JUNCTIONAL = no P wave associated, long pause, normal QRS complexes

VENTRICULAR = no P wave, long pause, more wide and bizarre QRS complex

36
Q

What is considered sinus tachycardia in dogs and cats? What is seen on ECGs?

A
  • DOGS = > 160 bpm
  • CATS = > 240 bpm

normal PQRST with high HR with little response to vagal maneuvers —> P wave can get hidden

37
Q

Is treatment needed for sinus tachycardia?

A

not always - typically physiologic

  • sustained = treat underlying cause
38
Q

What is occurring in this ECG?

A

sinus tachycardia

39
Q

What are some physiological, pathological, and drug-induced causes of sinus tachycardia?

A

PHYSIOLOGICAL - elevated sympathetic tone caused by stress, pain, anxiety, hypovolemia, or toxicities

PATHOLOGICAL - fever, hyperthyroidism, shock, anemia, infection, CHF, hypoxia

DRUGS - Atropine, Epinephrine, Vasodilators (hypotension increases HR)

(treat underlying cause!)

40
Q

What is indicative of sinus arrest/block on ECG? What is the most common cause?

A

disease in the sinus node or very high vagal tone cause the absence of sinus activity for > 2 RR intervals

pathologic > physiologic —> drug-induced (anesthetics), sinus nodal disease (sick sinus syndrome) > vagal mediation (brachycephalic)

41
Q

What is commonly also seen with sinus arrest/block? What is the most common clinical sign?

A

escape beats

signs of weakness/collapse, prolonged periods where there is a low heart rate

42
Q

What is occurring in this ECG?

A

sinus arrest/block

43
Q

What treatments are indicated for sinus arrhythmia, bradycardia, tachycardia, and arrest?

A

SINUS ARRHYTHMIA - physiologic, no treatment needed

SINUS BRADYCARDIA - look into stopping drugs/treating diseases that cause increased vagal tone; can eliminate with Atropine, Glycopyrrolate, or catecholamines; run the dog and see if it resolves

SINUS TACHYCARDIA - treat underlying cause of increased sympathetic tone; can slow sinus rate with Atenolol/Esmolol or vagal manuever but rarely indicated

SINUS ARREST - high vagal tone = parasympatholytics, sinus nodal disease or sick sinus syndrome = pacemaker

Small Animal Medicine II (57 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions