Brainscape's Knowledge GenomeTM

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


See full index

DMS EKG > Conduction Blocks > Flashcards

Conduction Blocks Flashcards

1
Q

Definition of conduction block

A

any obstruction or delay of the flow of electricity along the normal pathway

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

3 types of blocks:

A

sinus node block
AV block
bundle branch block

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

What does the EKG look like in a sinus node block

A

looks like a pause in the normal cardiac cycle

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

AV block occurs between

A

sinus node and purkinje fibers (includes AV node and His bundle)

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

what is a fasicular block/hemiblock?

A

only part of one of the bundle branches are blocked

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

First degree AV Block is what

A

prolonged delay in conduction at AV node or His bundle

-prolonged PR interval

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

Diagnosis of first degree AV block is

A

PR interval longer than .2s (1 big square)

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

Second degree AV block

A 
not every atrial impulse can pass through the AV node
-more P waves than QRS
2 types:
Mobitz type I
Mobitz type II
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

EKG of Mobitz type 1 block looks like

A

progressive lengthening of PR interval and then a dropped beat
starts again

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

Grouped beating seen in

A

2nd degree AV blocks

-Mobitz 1 & 2

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

Mobitz 2 usually due to block

A

below the AV node in the His bundle

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

EKG of Mobitz 2 looks like

A

two or more normal beats with normal PR interval and then a dropped beat

  • no progressive lengthening
  • ratio of p waves to QRS is constantly varying
  • QRS may be wide due to LV conduction delay
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What ratio makes it impossible to tell Mobitz 1 from Mobitz 2?

A

2:1
Pwave:QRS

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

General treatment for Mobitz1

A

Generally no treatment needed

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

General treatment for Mobitz 2

A

could progress to third degree heart block

may require pacemaker

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

Third degree AV block also known as

A

complete heart block

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

Response of heart for third degree AV block

A

idioventricular escape beat

AV dissociation occurs

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

EKG of Third degree AV block looks like

A

regular intervals of P waves and QRS but they do not correlate
QRS wide= ventricular origin
QRS narrow = being paced from AV junction
Atrial rate is always faster then the ventricular rate

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

PR waves of third degree AV block are

A

completely variable

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

What are stokes-adams attacks?

Treatment?

A

no ventricular escape rhythms with 3rd degree AV block
4 or more seconds without ventricular activity
-syncope or near syncope
Require pacemaker

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

A ventricular escape beat occurs after_____ and is _____ premature

A

after a long pause

never premature

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

Causes of third degree AV blocks:

A

Degeneration of conduction system (#1 cause)
Acute MI
-emergent pacemaker almost always required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Definition of bundle branch block

A

conduction clock in either the left or right bundle branches

24
Q

RBBB has what in leads V1 and V2

A

R’ in QRS
QRS= RSR’ (like rabbit ears)
QRS>.12 seconds

25
Q

Dx of bundle branch block is done by looking at

A

width and configuration of QRS complex

26
Q

What causes the wide negative S wave deflection in the left chest leads during RBBB

A

rightward spread of the delayed slowed RV depolarization

27
Q

LBBB shows QRS changes in leads

A

over LV:
I, aVL, V5, V6
-already have tall r waves
-now see prolongation and sometimes a notch

28
Q

During LBBB broad deep s waves are seen in

A

over RV: V1 and V2

29
Q

Wide QS in lead V1 and wide R wave in lead V6 with slight notching at peak is diagnostic of

A

LBBB

30
Q

Lead V1 has wider RSR’ and lead V6 has QRS is diagnostic of

A

RBBB

31
Q

Inverted T waves with slight ST depression in right precordial leads with wide QRS is diagnostic of

A

RBBB

32
Q

Inverted T waves with ST depression in left lateral leads with wide QRS is diagnostic of

A

LBBB

33
Q

RBBB can be seen in diseases of:

A

diseases of conduction system

otherwise normal hearts

34
Q

LBBB can be seen in

A

Rarely in healthy hearts

Reflects heart disease

35
Q

What is the critical rate?

A

Bundle branch blocks may occur at a particular heart rate

-slow rates the ventricles conduct normally, but above a certain rate the BBB develops

36
Q

The critical rate is directly related to_______

If the rate is very rapid_____

A

the time it takes a bundle branch to repolarize

If HR is so rapid the branch can’t repolarize, there will be a temporary block to conduction

37
Q

RBBB precludes the dx of

A

Right ventricular hypertrophy

-R waves are distorted

38
Q

LBBB precludes the dx of

A

Left ventricular hypertrophy

-R waves are distorted

39
Q

Hemiblocks refers to

A

block of just one of the fascicles of the left bundle branch

  • septal
  • left anterior
  • posterior
40
Q

Major effect that Hemiblocks have on EKG is

A

axis deviation

41
Q

Left anterior hemiblock leads to __________ deviation

A

Left axis deviation
between -30 and -90
-Normal QRS duration, no ST segment or T wave changes
-No other cause of deviation present

42
Q

Left posterior hemiblock leads to ________ deviation

A

Right axis deviation
between +90 and 180
-Normal QRS duration, no ST segment or T wave changes
-No other cause of deviation present

43
Q

left posterior hemiblock occurs in _____

A

diseased hearts

44
Q

A bifascicular block is

A

RBBB + hemiblock (left anterior or left posterior)

-only one fascicle supplying current to both ventricles

45
Q

RBBB + left anterior hemiblock EKG would show

A

QRS wider than .12sec , RSR’ in V1 & V2

+ Left axis deviation

46
Q

RBBB +left posterior hemiblock EKG would show

A

QRS wider than .12sec , RSR’ in V1 & V2

+ Right axis deviation

47
Q

RSR’ in V1 but QRS duration is between 0.10 and 0.12 seconds is called

A

Incomplete bundle branch block

48
Q

QRS widening >.10 seconds without the usual criteria for either bundle branch blocks or bifascicular block are called

A

nonspecific intraventricular conduction delay

49
Q

Popular type of pacemaker that fires when patients own intrinsic heart rate falls below threshold:

A

Demand pacemaker

50
Q

Dual chamber pacemakers are also called

A

AV sequential pacemakers

51
Q

3rd degree heart block with origin near the AV node, what kind of pacemaker would be used?

A

ventricular or AV sequential pacemaker

52
Q

With ventricular pacemaker EKG will show

A

following spike will be wide and bizarre like a PVC

  • LBBB pattern
  • retrograde p wave may be seen
53
Q

An atrial pacemaker EKG will show

A

spike followed by p wave and normal QRS

54
Q

A sequential pacemaker EKG will show

A

two spikes, one before the p wave and one before the QRS

55
Q

Cardiac resynchronization therapy is for pts with

A

heart failure associated with wide QRS and LV dysfunction

DMS EKG (9 decks)

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