Brainscape's Knowledge GenomeTM

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


See full index

Cardio Block > AV Heart Blocks > Flashcards

AV Heart Blocks Flashcards

1
Q

Which heart block is not a consistent delay of conduction / not a “true” heart block?

A

1st Degree

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

What is characteristic of a 1st degree block?

A

PR interval > 0.20 s

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

Who can 1st degree blocks happen in for no apparent reason?

A

Healthy people - especially young athletes.

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

What are some cardiac causes of 1st degree block?

A 
Myocardial ischemia
Acute MI (inferior)
Myocardial necrosis 
Degenerative disease of the AV node – can be age related 
Congenital anomalies 
Myocarditis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some non-cardiac causes of 1st degree block?

A 
Increased vagal tone 
Drugs – BB, CCB, digoxin, antidysrhythmics  
Hypo/hyperkalemia
Hypothermia
Hypothyroidism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the clinical manifestations of 1st degree block?

A

Often little or no clinical significance because all impulses conducted to ventricular

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

What is the treatment for 1st degree block?

A

No specific treatment - CO is unaffected

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

What is the prognosis of 1st degree block?

A

Can progress to a higher block, especially in the presence of an inferior MI

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

Describe the pathophysiology of a 2nd degree / Mobitz Type I / Wenckeback block.

A

Intermittent block at the AV node
PR interval progressively increases until QRS complex is dropped, then cycle repeats
More P waves than QRS complexes with patterned irregularity

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

What is the significance of a 2nd degree / Mobitz Type I / Wenckeback block being transient & reversible?

A

It can be resolved when then underlying condition is corrected.

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

Who can 2nd degree / Mobitz Type I / Wenckeback blocks happen in fro no reason?

A

Healthy people

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

What are the 2 main causes of 2nd degree / Mobitz Type I / Wenckeback block?

A 
Acute MI (inferior)
Acute myocarditis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some other causes of 2nd degree / Mobitz Type I / Wenckeback block?

A

Rheumatic fever
Cardiac surgery
AV node ischemia from R coronary a. occlusion
Drugs – BB, CCB, digoxin, quinidine, procainamide
Increased vagal tone
Electrolyte imbalance – hyperkalemia

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

What are the clinical manifestations of 2nd degree / Mobitz Type I / Wenckeback block?

A

There are signs of decreased CO if dropped ventricular beats occur frequently, such as chest pain & hypotension

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

What is the treatment of 2nd degree / Mobitz Type I / Wenckeback block?

A

If asymptomatic, no specific treatment.

If symptomatic, give O2 & start IV. Slow HR with atropine & transcutaneous pacing

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

What is the prognosis of 2nd degree / Mobitz Type I / Wenckeback block?

A

May progress to more serious blocks, especially in presence of inferior MI

17
Q

Describe the pathophysiology of a 2nd degree / Mobitz Type II block.

A

Intermittent block at bundle of His or bundle branches, that results in atrial impulses that are not conducted to ventricles. There are more P waves than QRS complexes & the duration of PR interval of conducted beats are constant.

18
Q

What is a 2nd degree / Mobitz Type II block considered int the ER?

A

Serious & malignant

19
Q

What are the 3 main causes of 2nd degree / Mobitz Type II block?

A

MI (anterior)
Degenerative disease of the AV node
Severe CAD

20
Q

What are some other causes of 2nd degree / Mobitz Type II block?

A 
Organic heart disease 
Cardiac surgery 
Myocarditis 
Rheumatic fever 
Drugs – BB, CCB, digoxin, quinidine, procainamide
Increased vagal tone 
Electrolyte imbalance – hyperkalemia
21
Q

What are some symptoms of 2nd degree / Mobitz Type II block?

A

Fatigue
Syncope
Hypotension
Altered mental status

22
Q

What is the treatment of 2nd degree / Mobitz Type II block?

A

Give O2, start IV, transcutaneous pacing. With new, wide QRS, give atropine while setting up transcutaneous pacing

23
Q

What is the prognosis of 2nd degree / Mobitz Type II block?

A

May progress to more severe heart block & ventricular asystole

24
Q

Describe the pathophysiology of a 3rd degree / complete heart block.

A

Complete block of conduction at or below the AV node.
Impulse from atria (which are stills stimulated by SA node at 60-100 bpm) cannot reach ventricles. The ventricles are stimulated from below the AV node.

25
Q

What is the ventricular rate in 3rd degree / complete heart block if the ventricles are stimulated by the AV junction & how does the QRS look?

A

40-60 bpm; narrow QRS

26
Q

What is the ventricular rate in 3rd degree / complete heart block if by ventricles are stimulated from the ventricles & how does the QRS look?

A

20-40 bpm; wide QRS

27
Q

What’s the most common cause of 3rd degree / complete heart block?

A

Congenital abnormality

28
Q

What are some cardiac causes of 3rd degree / complete heart block?

A 
Degeneration of conduction system – older adults
MI (anterior or inferior)
Cardiac surgery 
Servere CAD
Myocarditis
Rheumatic fever
Septal necrosis
29
Q

What are some non-cardiac causes of 3rd degree / complete heart block?

A

Drugs – BB, CCB, digoxin, quinidine, procainamide
Increased vagal tone
Electrolyte imbalance – hyperkalemia

30
Q

What are the clinical manifestations of 3rd degree / complete heart block?

A 
Well tolerated & asymptomatic as long as escape rhythm is fast enough to generate sufficient CO & maintain perfusion. Synchronized atria & ventricles can decrease CO if ventricular rate is slow. Symptoms of hypoperfusion include:
Fatigue
Syncope
Hypotension 
Altered mental status
31
Q

What is the treatment of 3rd degree / complete heart block?

A

Give O2, start IV, transcutaneous pacing.

With new, wide QRS – atropine while setting up transcutaneous

32
Q

What is the prognosis of 3rd degree / complete heart block?

A

May progress to more severe heart block & ventricular asystole

33
Q

What is the pathophysiology of AV dissociation?

A

Occurs when the atria & ventricles are under control of separate pacemakers & beat independently

34
Q

How is AV dissociation different from 3rd degree?

A

The ventricular rate is the same or faster than atrial ventricular rate is the same or faster than atrial. In 3rd degree – ventricular rate is slower than atrial

35
Q

What are some causes of AV dissociation?

A

Slowed / impaired SA node conduction
Conduction in AV junction or ventricles faster than SA node
Complete AV block
Anything interfering with atrial conduction to ventricles, such as pauses produced by premature beats

36
Q

What are the clinical manifestations of AV dissociation?

A

Vary depending on underlying cause

Signs of decreased CO if rate is reduced: hypotension, altered mental status, fatigue, syncope.

37
Q

What is the treatment of AV dissociation?

A

No treatment if cause is not significant. If CO is reduced, treat underlying problem:
Deliver atropine & other rate-accelerating agents
Pacemaker
Discontinue drug if that is the cause

Cardio Block (13 decks)

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