EXAM2/CH18- Cardiac Electrical Pathophysiology Flashcards

1
Q

____ % of the individuals who require pacemakers are over the age of 65 years

A

85%

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2
Q

85% of the individuals who require pacemakers are over the age of ____

A

65 years

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3
Q

____ pacemakers are implanted in the US each year

A

200,000

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4
Q

why is the number of pacemakers implanted growing?

A

because of the number of elderly people in the population

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5
Q

what 2 major factors increase need for a pacemaker

A

-CVD
-age

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6
Q

normal electrical conduction of the heart

A

SA node initiates the signal ->

signal passes through atria, stimulating contraction ->

AV node delays signal ->

bundle of His ferries the signal thru fibrous skeleton to interventricular septum ->

R+ L branches convey signal to apex ->

purkinje fibers carry signal thru ventricles, stimulating contraction from the bottom upward

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7
Q

what is the natural pacemaker where the heartbeat + depolarization is initiated

A

SA node

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8
Q

why does the AV delay occur

A

so that the ventricles cal fill

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9
Q

what does the apex do

A

separates R from L sides of the heart

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10
Q

sick sinus syndrome (SSS)

A

rhythm disorder involving the SA node
-individual has faulty SA node
-inability to generate a heartbeat or increase HR in response to the body’s changing circulation demands (if the SA node can’t generate a heartbeat, nothing else can happen)

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11
Q

sick sinus syndrome results in what 3 things

A

-bradycardia
-long pauses between heartbeats
-irregular heartbeats

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12
Q

symptoms of sick sinus syndrome

A

-heart palpitations
-angina
-fatigue
-light-headedness
-exercise intolerance
-syncope

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13
Q

syncope

A

brief loss of consciousness that occurs via fainting/passing out due to a sudden drop in blood flow to the brain

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14
Q

see slide 5 for SSS EKG

A
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15
Q

AV conduction block is also called

A

heart block

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16
Q

AV conduction block (heart block)

A

-loss of atrioventricular synchrony
-this is an issue with the AV node; SA node is working properly
-when the sa node is stimulated, it doesn’t pass the wave of stimulation to the AV node, so there is not an adequate contraction of the heart + the body does not get adequate bloodflow

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17
Q

AV conduction block or SSS is more life threatening

A

AV conduction block

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18
Q

symptoms of AV conduction block

A

similar to SSS

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19
Q

what is the body’s last ditch effort to generate a heart beat

A

junctional escape
-escape rhythms are not something you can survive off of past a few seconds/minutes

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20
Q

3 ultimate goals of pacemaker

A

-regular HR
-synchronize chambers of the heart (atrioventricular synchrony)
-defibrillate in case of arrhythmia

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21
Q

what 3 things make up the pacemaker (pulse generator)

A

-metal case (circuitry with battery)
-lithium batteries
-pacing leads (2 or 3)

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22
Q

where is the pacemaker implanted

A

just below the clavicle
-placed just below skin
-inferior to clavicle

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23
Q

how many pacing leads are in a pacemaker

A

2 or 3

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24
Q

pacemaker implantation

A

-fast, rather non-invasive
-can be done outpatient

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25
Q

describe the lithium batteries in a pacemaker

A

good because they last a long time (10+ years)
-given the time an individual has a pacemaker, we may need to go in to replace the battery

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26
Q

how does the pacemaker work

A

leads send sensory info to activity sensor that tells the pacemaker when to work
-where the leads get connected depends on what we are trying to fix with the pacemaker

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27
Q

3 types of pacemakers

A

-temporary external pacemakers
-permanent pacemakers
-AICD

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28
Q

temporary external pacemakers

A

-emergency
-ICU
-until permanent pacemaker placement

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29
Q

permanent pacemakers

A

the type of pacemaker we typically think of

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30
Q

AICD pacemakers

A

defibrillator

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31
Q

physiological pacing

A

sequence and timing of contractions between atria and ventricles to overcome CHRONOTROPIC INCOMPETENCE
-fixed rate vs. rate-responsive

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32
Q

chronotropic incompetence

A

when we don’t have the ability to generate a heartbeat
-pacemaker restores chronotropic competence

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33
Q

old school pacemakers were fixed rate or rate-responsive

A

only fixed rate

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34
Q

fixed rate pacemaker

A

pacemaker is limited to either lowering or increasing HR but doesn’t do both, only one or the other
-cardiologist will put a cap on the HR either on the lower or higher end

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35
Q

rate-responsive pacemaker

A

pacemaker can either increase or decrease HR when needed
-can go either direction

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36
Q

AV timing interval

A

signals ventricle to contract

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37
Q

optimal AV delay

A

how fast ventricle contracts

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38
Q

when is optimal AV delay

A

typically 150 ms from beginning of atrial depolarization

39
Q

maximal tracking rate

A

highest pacing rate allowed
-pacemaker will not make HR go any higher than the value set for this

40
Q

what is maximal tracking rate typically set at

A

110-150 bpm

41
Q

pacemaker is programmed to account for what

A

delay between SA + AV node

42
Q

if patient has problems with venous return, what would we change on pacemaker

A

AV delay

43
Q

single chamber

A

-1 lead to RA
-for bradycardia WITHOUT AV block

44
Q

dual chamber

A

-1 lead to RV
-1 lead to RA
-bradycardia WITH AV block

45
Q

what does single chamber fix

A

SSS

46
Q

what does dual chamber fix

A

heart block

47
Q

there are up to ____ letters in a pacemaker code

A

5

48
Q

pacemaker coding

A

how we set a pacemaker to work
-tells us what the pacemaker is programmed to do

49
Q

how do we change the settings on a pacemaker

A

put wand over pacemaker which uses bluetooth to change the settings of the pacemaker
-more patient friendly option

50
Q

pacemaker coding- A

A

atrial

51
Q

pacemaker coding- V

A

ventricle

52
Q

pacemaker coding- D

A

dual, both atrial + ventricle

53
Q

pacemaker coding- o

A

none, off

54
Q

pacemaker coding- T

A

trigger
-means increase

55
Q

pacemaker coding- I

A

inhibit
-means decrease

56
Q

pacemaker coding- D (for third)

A

dual, can either increase/decrease
-rate-responsive

57
Q

first letter in pacemaker coding means

A

tells us what chamber is being paced
-aka the chamber being targeted by the pacemaker

58
Q

options for first letter in pacemaker code

A

A, V, D, o

59
Q

second letter in pacemaker coding means

A

tells us where the pacemaker is receiving sensory information from
-chamber sensed

60
Q

options for second letter in pacemaker code

A

A, V, D, o

61
Q

third letter in pacemaker coding means

A

how the pacemaker responds

62
Q

options for third letter in pacemaker code

A

T, I, D, o

63
Q

third letter in pacemaker code- if T or I is selected…

A

we have fixed rate

64
Q

third letter in pacemaker code- if D is selected…

A

we have rate-responsive

65
Q

fourth letter in pacemaker coding means

A

programmable features

66
Q

options for fourth letter in pacemaker coding

A

P, M, R, o

67
Q

fourth pacemaker letter- P

A

rate + output

68
Q

fourth pacemaker letter- M

A

multiprogrammable

69
Q

fourth pacemaker letter- R

A

rate-responsive

70
Q

fourth pacemaker letter- o

A

none

71
Q

fifth letter in pacemaker coding means

A

multisite pacing OR dual function
-some pacemakers can defibrilate the heart

72
Q

options for fifth letter of pacemaker coding

A

P, S, D, o

73
Q

fifth pacemaker letter- P

A

pacing
-actively pacing

74
Q

fifth pacemaker letter- S

A

shock
-ONLY defibrillate, not pace

75
Q

fifth pacemaker letter- D

A

dual (P + S)
-we want pacemaker to both pace the heart + defibrillate when necessary
-not all pacemakers have dual functioning

76
Q

fifth pacemaker letter- o

A

none

77
Q

exercise testing for pacemakers

A

-ensure appropriate rate response with exercise
-can determine need for a pacemaker
-provides info to adjust the pacemaker for optimal function in response to exercise (i.e., exercise capacity)
-determines anginal threshold
-helpful when we already have pacemaker implanted, to test if it is working properly

78
Q

formal vs informal exercise testing for pacemaker

A

bruce protocol vs chronotropic assessment exercise protocol

79
Q

**why is chronotropic assessment exercise protocol useful for pacemaker patients

A

intensity very minimally increases
-VERY SMALL CHANGES to safely assess ability of pacemaker to respond accordingly

80
Q

ExRx special considerations- be familiar with the device

A

-fixed rate vs. rate-responsive features
-abrupt decreases in heart rates
-variation in heart rate responses based on the mode of activity + type of rate-responsive sensor in the pacemaker

81
Q

ExRx special considerations- mode

A

all modes are acceptable, except for any activity that involves direct contact to the pacemaker (contact sports, lying prone on floor, etc.)

82
Q

ExRx special considerations- communicate with patient’s physician

A

feedback about HR, BP, + symptopmatic responses to exercise

83
Q

because we can’t rely on HR to determine intensity of exercise with pacemaker patients, what is our next best bet

A

RPE

84
Q

**no 2 pacemaker patients are alike

A
85
Q

**know Dr.Gardner’s take aways from other lectures for this

A
86
Q

AICDs

A

automatic internal cardioverter defibrillators

87
Q

who are AICDs prescribed for

A

HIGH-RISK CANDIDATES
-potential lethal ventricular tachycardias
-survived previous sudden death events
-high risk for recurrent cardiac arrest
-high risk for cardiac arrest; prior myocardial injury

88
Q

why do high risk individuals need AICD (aka an implanted defibrillator)

A

because it delivers the same shock as defibrillator paddles do in the case that they need this on the sport

89
Q

how do AICDs work

A

-implanted like a pacemaker
-battery-operated
-delivers shock when life-threatening arrhythmia is detected

90
Q

can AICDs be combined with a pacemaker

A

YES
-we also have pacemakers that can do both pacing + defibrillating

91
Q

AICD appearance

A

works + looks the exact same as a pacemaker

92
Q

does an implanted defibrillator work 24/7

A

no, but it SENSES 24/7
-only delivers a shock when needed

93
Q

major concern in AICD exercise

A

avoid reaching threshold HR that will cause the device to shock

94
Q

training HR for someone with an AICD should stay ____ bpm below the present HR that produces a shock

A

20 bpm below
-the defibrillator can pick up on the speed of HR, but cannot differentiate if it is caused by exercise or TRUE tachycardia when they actually need the shock
-faulty shock is incredibly dangerous because if exercise induced it could put them into a life threatening condition