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ECG 7150/7220 > junctional/ventricular/atrioventricular > Flashcards

junctional/ventricular/atrioventricular Flashcards

1
Q

where is the first place to backup or kick in if impulse fails from the SA node?

A
  • the AV junction
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2
Q

are there impulse forming cells in the AV node?

A

no. but there is in the junctional tissue

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3
Q

what is PJC

A

Premature Junctional Contraction:

- when impulse-forming cells fires ‘earlier’ than regular interval

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4
Q

will there be a P wave in PJC? explain

A

Yes. But they will look different from each other (if visible) d/t PJC traveling through atria in different manner

depolarization starts at the AV junctin and proceeds from there

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5
Q

3 key facts for PJC atrial depolarization and P waves

A
  1. P wave represents atrial depolarization NOT SA node depolarization
  2. Impulses arising in the AV junction will create atrial depolarization
  3. P waves associated with junctional rhythms (like PJC’s) can occur in different shapes or may be hidden in other parts of the ECG waveform
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6
Q

The P wave of a PJC can appear in three ways:

A
  1. inverted - from junction, if wave goes to the atria first and then to vents, you will see inverted P wave preceding QRS (inverted d/t atrial depolarization occurring in retrograde manner)
  2. Buried in QRS complex - if depolarization goes into the vents and the atria at the same time, then the P wave is usually buried in the QRS complex.
  3. Occur after the QRS complex - if the vents are depolarized before the atria, then P wave usually occurs after QRS
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7
Q

What happens to the PR interval in a PJC?

A
  • the location of the P wave impacts the PR interval bc if the impulse originates at the AV junction the distance to travel to atria is less than normal (0.12 sec) and would precede the QRS
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8
Q

PJC’s can occur as?:

A

single isolated beats or as clusters/groups

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9
Q

what is JER?

A

Junctional Escape Rhythm
- when a secondary site in the junctional tissue takes over role of impulse formation: usually occurs when the primary pacemaker site in the SA node fails

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10
Q

what is a normal rate for JER? what if it is greater than normal?

A

Normal 40-60 BPM

If greater than Accelerated Junctional Rhythm

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11
Q

explain the P wave in a JER:

A
  • similar to PJC, the impulse at the junctional tissue will depolarize in a retrograde manner
  • the P wave will be inverted, buried or after a QRS
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12
Q

what does the QRS look like in JER?

A

It appears normal

bc the wave of depolarization follows the normal pathway after it leaves the junction

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13
Q

what does the interval and rhythm look like in JER?

A

the R-R is constant and rhythm is regular

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14
Q

JER

conduction prob:

A
  • prob with the SA node
  • is the rate sufficient to meet the PTs needs.
  • it is similar to sinus brady
  • assess PT to determine their response
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15
Q

JER

cause

A

whatever caused the SA node to fail

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16
Q

JER

implication to O2 supply and demand

A

The impact the rhythm has on CO

  1. Slow HR
  2. Loss atrial kick
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17
Q

JER

intervention

A

assess PT

IF CO compromised by rhythm then atropine

if no response then temporary transvenous pacemaker

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18
Q

JER

Rate
Rhythm
P wave
PR interval
QRS complex
A

rate: 40-60
rhythm: reg

P wave: before, during or after QRS (if visible, may be inverted)

PR: if present 0.12 sec or less

QRS: 0.10 sec or less

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19
Q

what is the difference between Junctional Tachycardia and Junctional Escape rhythm and Accelerated Junctional Rhythm?

A

The rate of firing of junctional focus
JT = > 100 / min
JER = 40-60
AJR = 60-100

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20
Q

which rhythms depolarize in retrograde fashion?

A

JER, PJC and JT

then conduction through the vents are normal

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21
Q

Junctional Tachy

conduction problem

A

junctional tissue around AV node

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22
Q

Junctional Tachy

Cause

A

whatever caused SA node to fail allowing junctional tissue to take over

dig. tox, MI, HF…

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23
Q

Junctional Tachy

Intervention

A

assess PT
If CO compromised by rhythm, treat cause

amiodarone, BB, CCB, ablation

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24
Q

What is SVT and which dysrhythmias are in the category?

A

Dysrhythmias with fast rate whose site of impulse formation is above the vents.

  1. Atrial fibrillation
  2. Atrial flutter
  3. Atrial Tachycardia
  4. Junctional Tachycardia

sinus tachy, multifocal atrial tachy

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25
Q

SVT criteria

A
  1. No defined P wave
  2. vent rate > 150 (meaning impulse not originates from SA node
  3. QRS complex is normal ( 0.10 sec or less) means that normal pathway from AV node, so not originating from vents. So atria or junctional
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26
Q

When are ventricular rhythms fast?

A

When irritable focus or multiple foci ‘take over’ from pacemaker site ‘higher up’ in the conduction system (ex. override pacemaker sites in SA node or junctional tissue)

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27
Q

When are ventricular rhythms slow?

A

When SA node or AV junction pacemaker sites fail (or completely blocked), and pacemaker site in the conduction system below the AV junction assumes the pacemaker role

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28
Q

unifocal and multifocal PVC?

A

same and more than one abnormal focus.

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29
Q

ventricular bigeminy

A

every second beat is a PVC

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30
Q

vent trigeminy

A

every third beat is a PVC

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31
Q

Couplet

A

2 PVC’s together

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32
Q

Triplet

A

3 PVC’s together

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33
Q

Run

A

more than 3 PVC’s together

34
Q

post cardiac arrest management: induced therapeutic hypothermia is for?

A

PTs who have been resuscitated from cardiac arrest associated with vent fib and pulseless vent tachy but DO NOT gain some level of consciousness post-defib

35
Q

what is induced therapeutic hypothermia?

A

deliberately cooled to goal core temp of 32-34C

target being reached in 4 hours of return of spontaneous circulation (ROSC) ex. a perfusing rhythm

36
Q

why induced therapeutic hypothermia?

A

> out of hosp cardiac arrest survivors have high incidence of significant, permanent neurological deficit from cerebral edema and other neurological damage resulting from hypoxia and brain anoxia

> ischemia result in loss of cell membrane integrity and increased permeability, electrolyte shifts and metabolic acidosis = temp or permanent change in neurological function

37
Q

what is the goal of induced therapeutic hypothermia?

A

focus on blocking or minimizing the destructive processes that arise from cellular anoxia (complete absence of O2; severe hypoxia)

38
Q

process of induced therapeutic hypothermia

A

hypothermia blankets or ice packs. NS cold lavage may be used

  • PT kept cool for 12-24 hours before controlled warming
  • rewarming goals = increasing temp by 0.2C to 0.5C/hour is important to avoid negating the therapeutic effects gained by hypothermia period
39
Q

specific criteria for induced therapeutic hypothermia:

A
  1. primary dysrhythmia: Vent fib or V. tach
  2. time from collapse to ACLS (advance cardiac life support) < 15 min
  3. Time from collapse to ROSC (return of spontaneous circulation) < 60 min (pulse and BP present)
  4. adult > 18
  5. persistent GCS < 10
40
Q

these things will exclude PTs from induced therapeutic hypothermia:

A
  1. pregnant
  2. Hx of terminal illness
  3. improving neurological status (making purposeful movements)
  4. coma/arrest secondary to non-cardiac factors
  5. persistent hypoxia (SaO2 < 85% for > 15 min)
  6. significant coagulopathy
  7. hemodynamic instability despite vasopressors: MAP < 60mmHg for > 30min
41
Q

clinical significance of AV block depends on: 3

A
  1. degree (severity ) of block
  2. rate of secondary pacemaker
  3. PTs response to the ventricular rate
42
Q

If there is a pacemaker spike on the ECG strip not followed by a contraction complex what are you seeing? Failure to

A

Capture

43
Q

The 3 letters in the pacemaker code stand for what in the appropriate order?

A

a. Chamber paced, sensed, how to respond to a sensed event

44
Q

what is failure to pace?

A

failure to fire- complete lack of pacemaker activity. no spike.

spike/response - spike/response - no spike/no response - spike response

could be battery, circulatory, leads, disconnect…

45
Q

what is failure to capture?

A

when electrical impulse is emitted from the generator but fails to depolarize the myocardium.

Spike but no response**

you see a pacemaker spike on ECG that is NOT followed by appropriate ECG waveform (atrial or vent response)

caused: anything that makes it more diff for the electrical impulse from the pulse generator to cause depolarization of cells (transvenous/electrode wires out of position**, voltage too low, metabolic acidosis, electrolyte imbalance, myocardial ischemia).

check connections and strength of electrical discharge: reposition PT**, increase output setting, review for PT related issues, contact MD

46
Q

what is failure to sense?

A

** pacemaker spikes that fall where they shouldn’t. Anywhere in the cycle**

  1. oversensing–> when pacemaker senses extraneous (non-cardia) electrical signals. (muscle tremors) that lead to pacemaker being inappropriate inhibited or triggered
  2. undersensing–> if the sensitivity setting is such that a larger electrical activity needs to be generated in order for the pacemaker to recognize it, then good possibility that PTs intrinsic activity will not be recognized or sensed. can be life threatening
    - If Pacemaker doesnt know that there is intrinsic activity, it will continue to fire, emitting electrical activity to PTs heart. can cause life-threatening dysrhythmia
    - recognize- spike may occur in the middle of QRS
47
Q

For arrhythmias would you need a pacemaker? 5

A
  1. sinus brady
  2. sinus arrest/block
  3. JER
  4. VER
  5. AV blocks
48
Q

what is the diff btwn atrial and junctional tachy?

A

Atrial might not have any P waves because they might be hidden in the QRS.

Junctional will have inverted or weird P waves

49
Q

Chamber paced:

A

Where it creates impulse

0= none
A = atrium
V = vents 
D = Dual
50
Q

Chanmber sensed:

A

senses intrinsic electrical activity

0= none
A = atrium
V = vents 
D = Dual
51
Q

Response to sensing:

A

denotes what the pacemaker will do

0 = none
T = triggered
I = inhibited
D = dual (applies to permeant)
52
Q

Most common mode of vent pacing?

A

VVI = ICU

53
Q

asynchronous contraction of the atria and ventricles =?

A

loss of atrial kick with ventricular filling. = decreased CO

54
Q

If the lead is placed in the atria…

A

you will have a spike and then P wave followed by QRS

55
Q

If the lead is placed in the vent you will see

A

no p wave, spike and wide bizarre QRS

56
Q

if you see a pacemaker spike not followed by a P wave or QRS that means?

A

failure to capture

difficult for the electrical impulse from the pulse generator to cause the cells to depolarize. These can be patient-related issues such as acidosis, electrolyte imbalance, and myocardial ischemia,

reposition pt so lead closer to the surface of the heart

57
Q

The 4th beat is the patient’s intrinsic beat. Close after that, we can see a pacer spike

A

Failure to sense. doesnt sense the PTs intrinsic beat and fires after

decrease mV setting

58
Q

If there is a pacemaker spike on an ECG strip not followed by a contraction complex what are you seeing?

A

failure to capture

59
Q

What pacemaker setting most mimics the normal heart activity thereby maintaining the closest CO as a healthy heart would?

A

DDD - 4 morphologies

60
Q

In a synchronous pacemaker, failure to sense is represented on an ECG rhythm strip by

A

a pacemaker spike not followed by a contraction/complex

61
Q

sensed activity…

A

inhibits pacing

62
Q

if 100% vent paced you cannot…

A

have the ability to assess sensed

63
Q

In a synchronous pacemaker, failure to sense is represented on an ECG rhythm strip by

A

A spike in the presents of intrinsic activity

64
Q

which rhythms need cardioversion as interventions?

A
  1. uncontrolled A.fib
  2. A. flutter
  3. vent tachy
65
Q

which rhythms need pacemaker?

A
  1. JER
  2. Blocks
  3. Bradycardia
66
Q

with what rhythms do you defibrillate?

A

anything with no pulse

  1. Vent fib
  2. pulseless vent tachy
  3. SVT (A. fib, A flutter, A. tach, J tach)
67
Q

why does the Dr. perform and carotid massage?

A

to stimulate the vagus nerve to decrease the HR

decrease AV conduction rate

68
Q

cardioversion timed with?

A

R wave. Avoid T wave timing to avoid refractory period of the cycle. The machine searches for QRS and flags it

R on T can cause? V. tach

69
Q

what do you need to remember for vent tachy?

ACLS Too fast:

A

wide QRS
is there a pulse or no pulse?

pulseless- ABC, code, IV, intubate, defib/CPR**, EPI* (also applies for pulseless Vent Fib)

pulse- stable? = drugs (Adenosine, Amiodarone, BB, CCB)

Pulse unstable = cardioversion

70
Q

what is the difference between defibrillation and cardioversion?

A

Defib is done with pulseless and is non-synchronized

Cardiovert- with pulse, synchronized with R waves

71
Q

ACLS too slow:

A

: SB, Junctional escape or Brady, VER, 2AVB, 3AVB

Stable: monitor

Unstable: drugs = atropine, dopamine, Epi
: pacemaker

72
Q

When you see a PVC, what is the meaning of the ST?

A

because they are from the vents they are abnormal so the ST is not significant

73
Q

paroxysmal SVT

A

starts and stops abruptly. It will go away and the PT is fine

74
Q

1st degree considerations:

A

1P:1QRS

Sinus Rhythm with PR prolonged, but constant

75
Q

2nd degree type 1 considerations:

A

PR lengthens and then drops

When drops there is an extra P and no QRS

76
Q

2nd degree type 2 considerations:

A

More P than QRS’s

PR prolonged but will be the same length for all complexes

77
Q

3rd degree considerations:

A

QRS is wider > 0.12 if from vents, or narrow if from below junction. influenced by site of AV block
P-P is regular and R-R is regular
** there is no relationship between P’s and QRS’s

78
Q

Does ST matter in heart blocks?

A

Depends where QRS is coming from.

If narrow = from junction then it matters

If wide = from ventricles/purkinji then does not matter

79
Q

Any rhythm can be a PEA except…

A

VT, VF and asystole

80
Q

which meds slow the HR?

stable PTs:

unstable PTs:

A

for stable PTs:
For narrow and wide QRS (A.tach, A. fib, JT…. VT)

  • Amiodarone (Na, K, BB, CCB)
  • Adenosine

unstable:
cardiovertion

81
Q

which meds are used to speed up HR?

unstable PTs:

stable:

A

for unstable PTs:
(SB, junctional, VER, 2AVB, 3 AVB)

  • Atropine
  • Dopamine
  • Epi

Stable: monitor

82
Q

what can you give to no pulse, asystole, and PEA?

A

Epinephrine

ECG 7150/7220 (6 decks)

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