III. Cardiac Support Devices Flashcards
(148 cards)
1
Q
3 different implantable devices
A
- Implantable Permanent Pacemaker
- Implantable Cardioverter Defibrillator
- Intra-aortic Balloon Pump
2
Q
Implantable Permanent Pacemaker is for
Treatment of ____
A
bradycardia
3
Q
Implantable Cardioverter Defibrillator
is for treatment of ____.
A
tachycardia and fibrillation
4
Q
Intra-aortic balloon pump is for treatment of
____.
A
Left ventricular support
5
Q
PM of today
____ lead placement
A
Transvenous
6
Q
Goals of pacemakers today
A
A satisfactory heart rate to maintain effective cardiac output
A chrono-tropic physiological response
Atrio-ventricular synchronization
Inter-ventricular and intra-ventricular synchronization
Treat or prevent arrhythmias
7
Q
routes of temporary pacing
A
transvenous, transcutaneous/transthoracicesophageal
NOT trans-arterial
8
Q
indications for temporary pacing
A
Unstable Brady-dysrhythmias
Atria-ventricular heart block
Unstable tachydys-rhythmias
9
Q
temporary pacing
Endpoint is reached after:
A
a resolution of reversible problem or permanent pacemaker implantation.
10
Q
Indications for Permanent Pacemaker
A
- Sick sinus syndrome
- Tachy-brady syndrome
- Symptomatic sinus bradycardia
- A-fib with slow ventricular response
- 3rd degree heart block
- Chronotropic incompetence (Inability to increase heart rate to match exercise)
11
Q
Permanent Pacemaker Indications
Non-indications
A
- Syncope of undetermined etiology
- Asymptomatic sinus bradycardia
- Asymptomatic 1° & 2° Mobitz Type 1 AV Block
- Reversible AV block
- Long QT syndrome or Torsades de pointes due to a reversible cause
12
Q
Computerized device taht regulates the timing and sequence of one’s heartbeat
A
pacemaker
13
Q
Pacemaker Basics
Detect the ____ activity (sense)
A
intrinsic
14
Q
pacemaker system components
A
- pulse generator
- lead/s (encased in silicone)
- Programmer
15
Q
benefits of lithium-diode battery (power source)
A
- 5-15 yr life
- voltage decrease gradually
- sudden failure UNLIKELY
16
Q
battery placement
A
under submuscular plane of the pectoralis major
17
Q
computer component of PM?
A
pulse generator
18
Q
3 functions of PM circuitry
A
- time
- sensing
- output
19
Q
pacemaker sizes pic
A
today we use <30cc
20
Q
Leads placed via central access & fixed to ____.
A
endocardium of RV or RA
21
Q
Distal attachment methods:
A
Active fixation → metal screw-in
Passive fixation → rubber fins/wingtips or tines
22
Q
Pacing Leads Variety Pic
A
23
Q
____ fixation has porous carbon for improved contact and decreased pacing thresholds.
A
passive
24
Q
Pacemaker Implant Pic
A
25
3 locations of PM access
- R/L subclavian vein
- cephalic vein
26
# Pacing & Depolarization of Myocardial Tissue
The myocardium must be ____ (not in refractory period)
excitable
27
# Pacing & Depolarization of Myocardial Tissue
The stimulus current density (current per cross-sectional area) must:
1. Must be sufficiently ____
2. Sufficient ____
3. Lead in good position & with ____ with myocardium
high
duration
sufficient contact
28
# Pacing & Depolarization of Myocardial Tissue
The pacemaker-generated impulse then relies on the ____ properties of the cardiac specialized conduction & myocardial tissue for depolarization of the entire heart (aka: ____)
intrinsic
AKA: "capture"
29
# Sensing
Sensing is the detection of ____.
real or spontaneous cardiac depolarization
30
Factors that affect sensing:
- Electrode size
- Configuration of electrode
- Position of the lead tip within the heart and contact to the myocardium
- Programmed sensitivity level
31
Types of Pacemakers
Unipolar vs. Bipolar vs. Multipolar
Single vs. Dual Chamber vs. Multisite
Asynchronous vs. Synchronous
Programmable vs. Non-programmable
32
# Polarity of the Pacemaker System
Unipolar → ____
Bipolar → ____
Multipolar → ____
Unipolar →** highest sensitivity for sensing**
Bipolar →** improved rejection for more reliable sensing**
Multipolar → **special purpose leads**
*Quadripolar → Targeted cardiac resynchronization.*
33
# Unipolar Pacemaker Circuit
Larger “antenna” for sensing → Bigger signals, but more ____
interference
34
# Unipolar Pacemaker Circuit
Large circuit (____ cm) b/t single electrode at distal end of lead and the pulse generator
± 40-60cm
35
# Unipolar Pacemaker Circuit
____ unipolar → cases where AV conduction is likely to return.
____ unipolar → normal AV conduction w/ SA node disorder.
Ventricular
Right atrium
36
# Unipolar Pacemaker Circuit
Advantages:
High sensitivity for sensing
Large pacemaker spikes on ECG (easy interpretation)
37
# Unipolar Pacemaker Circuit
Disadvantages:
Extracardiac stimulation possible (pectoral pocket muscle)
Sensing of extracardiac signals (i.e. detecting ventricular depolarization from atrial lead)
Non-physiological interference
38
# Bipolar Pacemaker Circuit
Short circuit (____mm) between 2 electrodes at the distal end of the lead
± 10-15
39
# Bipolar Pacemaker Circuit
Advantages:
Improved rejection of extra-cardiac and/or non-physiologic stimulation = More reliable sensing
40
# Bipolar Pacemaker Circuit
Disadvantages:
Small pacemaker spikes (difficult interpretation of pacemaker ECG)
41
____ pacing (i.e. AAI)
Limited indications in pts. with SSS and intact conduction system or for anti-tachycardia purposes
Single chamber atrial
42
Single chamber ventricular pacing (i.e. VVI):
Less expensive; non-physiological loss of AV synchrony; loss of around ____% CO
25
43
# Single Chamber Pacemakers
Preferred only in chronic atrial fibrillation and heart block, or those with very limited activity
Single chamber ventricular pacing (i.e. VVI):
43
# Single chamber ventricular pacing (i.e. VVI):
____% incidence of pacemaker syndrome
15
44
“Sequential” pacemaker = electrodes in RA and RV → allows AV synchrony
Dual Chamber Pacemakers
45
Allows physiological variability of pacing rate
Dual Chamber Pacemakers
46
# Dual Chamber Pacemakers
Advantages:
**Increase/decrease** of the cardiac output
Improved ____
**No ____ syndrome** [TQ]
Increase
Quality of Life
Pacemaker
47
# Dual Chamber Pacemakers
Disadvantages:
Expensive & complex
V-V dys-synchrony possible
Inter-channel interferences possible
48
# Multi-site Pacemakers: Dual Site Atrial Pacing
Leads placed at:
Atrial leads ____, other in the ____
Ventricular lead in the ____ at the apex or outflow tract.
RA appendage
coronary sinus
RV
49
# Biventricular pacemakers
Leads placed at: ____, ____, ____
RA, RV, & LV
50
# Biventricular pacemakers
Useful in the management of patients with heart failure who have evidence of ____ & ____
abnormal intraventricular conduction (i.e. LBBB)
V-V dys-synchrony.
51
Fixed Rate (Asynchronous) Modes:
AOO →
VOO →
DOO →
Fixed rate atrial pacing (asynchronous)
Fixed rate ventricular pacing (asynchronous)
Fixed rate AV sequential pacing (asynchronous to intrinsic rhythm)
52
# Fixed Rate (Asynchronous) Modes
T/F: Impulse produced at a set rate with no relation to patients intrinsic cardiac activity.
true
53
# Synchronous Pacing
Can mimic ____ pattern of the heart
intrinsic electrical activity
54
# Pacemaker Codes & Modes
1st letter →
chamber Paced
55
# Pacemaker Codes & Modes
2nd letter →
chamber Sensed
56
# Pacemaker Codes & Modes
3rd letter →
Response to chamber sensed
57
# Pacemaker Codes & Modes
4th letter →
Programmable features
58
# Pacemaker Codes & Modes
5th letter →
Anti-tachycardia response
59
Pacemaker Codes & Modes Table Pic
60
Response to sensing options (3)
I (inhibited) → Withhold a pacemaker output in response to a sensed event.
T (triggered) → Produces output spikes coincident with the sensed signal.
D (dual) → I and/or T
61
4th - Programmable Options
**O (none)** → not programmable
**P (simple programmable)** → limited to 3 or fewer programmable parameters
**M (multiprogrammable)** → device can be programmed in more than 3 parameters
Rate, sensing, output, refractory periods, mode, hysteresis
**C (communicating)** → capable of transmitting or receiving data for informational or programming purposes.
**R (rate responsive)** → device is capable of a rate responsive function
62
Most bradycardia devices are what (4th) programmable option
O (none)
63
5th — Anti-tachycardia Responses (4)
O (none) → Not activated
P (paced) → pace the patient out of tachycardia
S (shocks) → deliver a defibrillating shock
D (dual) → paced and shocks (MOST ICDs)
64
- Fixed rate ventricular pacing (no sensing or response)
- Asynchronous pacing
- Indications:
Temporary mode sometimes used during surgery to prevent interference from electrocautery.
- Monitor for R on T with ESU diathermy → torsades de pointes
VOO
65
- Ventricular pacing and sensing
If no intrinsic electrical impulse sensed → paced at a pre-set rate
If intrinsic electrical impulse sensed → pacing inhibited
- Asynchronous pacing
- Indications: Combination of high grade AV block and chronic atrial arrhythmias (particularly A-fib)
- VVIR = as above but adds rate-adaptive mechanism for exercise
VVI
66
- Paces + Senses both atrium and ventricle
* If no intrinsic electrical impulse sensed → triggers pacing (EKG – 2 spikes)
* If intrinsic electrical impulse sensed → pacing inhibited
* AV Synchronicity maintained (“Sequential")
DDD
67
# DDD
Indications:
Combination of AV block and SSS
Pts. w/ LV dysfunction and LV hypertrophy who need coordination of A & V contraction to maintain adequate CO
68
# DDD
adds rate-adaptive mechanism for exercise
DDDR
69
Atrium paced, Atrium sensed, & will inhibit if intrinsic electrical impulse
AV Synchrony maintained
AAI
70
# AAI
Indications
Sick sinus syndrome in the absence of AV node dz. or A-fib.
71
Failure to Capture
72
Ventricular Pacemaker
73
Rate responsive pacing is influenced by what three variables
1. activity sensors (accelerometers)
2. Motion
3. Ventilation
74
Pacemaker complications apperent on EKG:
1. Failure to Output
2. Failure to Capture
3. Sensing Abnormalities
75
what is occuring?
failure to sense
76
what is occuring
77
# Pacemaker Syndrome
Low CO and heart failure like manifestations that happens in about 15% of pts with VVI or VOO pacemakers as a result of _____.
loss of AV synchrony.
78
# pacemaker syndrome
Atria contract against closed valves = ____ waves
(cannon A waves)
79
# Pacemaker Syndrome
Symptoms:
Vertigo/Syncope (worsens with exercise)
Unusual fatigue
HoTN
Cyanosis
Jugular vein distention
Oliguria
Dyspnea/SOB
Altered mental status
80
# Pacemaker Syndrome
Treatment:
establish normal AV synchrony
81
Pacemaker Syndrome EKG Pic
82
- Designed to treat a cardiac tachydysrhythmia
- Performs cardioversion/defibrillation
- ATP (antitachycardia pacing)
- Some have pacemaker function (combo devices)
Automatic Implantable Cardio-Defibrillator (AICD or ICD)
83
Biventricular pacemakers that are combined with an implantable cardioverter defibrillator (ICD) do not tend to last as long — ____ years
about two to four years.
84
AICD Functions
Antitachycardia Pacing
Cardioversion
Defibrillation
Bradycardia Pacing
85
- Generally used in patient’s who experienced a previous cardiac arrest
- Patients with undetermined origin of, or continued, VT or VF despite medical interventions
AICD
86
Antitachycardia Pacing Pic
87
ICD Cardioversion Pic
88
ICD Defibrillation Pic
89
____ delivers an asynchronous shock of energy.
Defibrillation
90
____ delivers a reduced shock of energy in synchrony with QRS complex.
Cardioversion
91
What type of PM shock is delivered if patient is in V-Fib?
ICD Defibrillation,
*Once out of V-Fib, PM will pace asynchronously (VVI mode) until the device is reset by healthcare provider*
92
A magnet placed over the pacemaker does what?
- converts to *asynchronous* mode (will not sense/defibrillate/cardiovert)
93
If a magnet is placed over the heart, and the PM is disabled, what function does the PM retain?
ability to pace
94
A procedure above what level should present some concern for PM interference?
umbilicus
95
Using a magnet to disable the PM is appropriate for a/an ____ procedure.
emergent
*if procedure is non-emergent, a rep will disable in pre-op*
96
What is convenient about using Neo in conjuction with PM patients?
No reflex bradycardia
97
Steps to take if patient with AICD codes:
**1. Start CPR & Defibrillate**
98
T/F: If pt with AICD codes, removing the magnet is a reliable method of defibrillating patient.
FALSE
*magnet 'likely' deprogrammed AICD, now requires provider to reset*
99
Person giving CPR may feel slight buzz if AICD functions
A 30-joule intra-cardiac shock is ____ j on skin
<2 J
100
# Coding pt with AICD
Change paddle placement if unsuccessful attempt:
Try ____ paddle placement if Anterior-Lateral unsuccessful.
Anterior-Posterior
101
External defibrillation **will/will not** not harm AICD
will not
102
A counterpulsation system that is used to give temporary support to the LV by mechanically displacing the blood w/i the aorta.
Intra Aortic Balloon Pump (IABP)
*one of the most common modalities of augmenting circulatory support*
103
How does the IABP work?
It optimally times inflation and deflation contractions of the heart
104
What are the advantages of using a IABP?
1. ↓LV systolic work, LVEDP & Wall Tension
2. ↓O2 consumption
3. ↑CO, Pefusion, CPP (Coronaries)
105
What patients most often require a IABP?
HF and/or cardiogenic shock
106
# IABP Placement
A flexible catheter with long balloon mounted on the end → inserted via ____ → placed in ____
femoral artery
descending aorta
107
# IABP
Balloon is inflated to displace blood in ____(“counter pulsation”)
When inflated, balloon blocks ____
aorta
85-90% of aorta.
108
# IABP
Sudden inflation = moves blood ____ and ____ to balloon (inc. pressure).
superiorly
inferiorly
109
# IABP
when does the IABP balloon inflate?
immediately after aortic valve closure (during diastole)
*after LV contraction ejected blood through aortic valve into aorta; but heart is weak and is unable to contract hard enough to circulate blood effetively. That is why the balloon pump then inflates, forcing blood superiorly, into **coronary arteries**, and inferiorly to distal organs.*
110
# IABP
What is caused by balloon inflation?
1. ↑ aortic pressure
2. ↑ Coronary Perfusion Pressure & BF
3. ↑ Systemic Perfusion Pressure
4. ↑ O2 supply to both the coronary and peripheral tissue
5. ↑ Baroreceptor Response
6. ↓ Sympathetic Function = ↓HR, ↓SVR, ↑LV Function
111
The balloon remains inflated throughout the entirety of what part of cardiac cycle?
diastole
112
# IABP
Triggered to deflate during:
opening of the aortic valve (onset of systole)
*to allow blood volume to enter aorta, so that it may be soon pumped out*
113
# IABP
Deflation creates a "____" in the aorta (↓volume and ↓pressure) = reduced impedance to ____.
potential space
LV ejection
114
# IABP
What are the cardiac effects of deflating balloon?
1. ↓afterload → ↓ myocardial oxygen consumption (MVO2)
2. ↓peak systolic pressure → ↓LV work.
3. ↑CO
4. ↑EF & forward flow
(Normal EF = 50-70%)
115
IABP Hemodynamic Effects Table Picture
116
Indications for IABP
- Refractory unstable angina (despite maximal medical management)
- Persistent myocardial ischemia
- Cardiogenic shock
- Acute mitral regurgitation
- Perioperative treatment of complications due to myocardial infarction
- Failed PTCA (Percutaneous transluminal coronary angioplasty)
- As a bridge to cardiac transplantation
(15-30% of end-stage cardiomyopathy pts. awaiting transplantation need mechanical support.)
- During or after cardiac surgery
(Cardiac failure / weaning from CPB)
116
# IABP
Contraindications
- Severe aortic insufficiency
- Aortic aneurysm
- Aortic dissection
- Limb ischemia
- Thromboembolism
- Uncontrolled sepsis
- Severe PVD
- End-stage heart dz. with no anticipation of recovery.
117
IABP Components Picture
118
list IABP 2 major components
1. Double-Lumen catheter w/ balloon
2. Console w/ pump to drive the balloon
119
size of IABP catheter
7.5-9.5 Fr
120
# IABP
IABP balloon capacity
30-60 mL
121
how is the IABP sized?
based on pt height
122
How many lumens does the catheter have?
2
- gas exchange (blowing up balloon)
- monitoring central aortic pressure
123
2 different gases used to inflate balloon
1. helium
2. CO2
124
Helium vs CO2
| Pros & Cons
Helium:
- lower density, inflates/deflates faster
- risk of air embolism if balloon rupture
CO2:
- Safer, dissolves into blood quickly
- slower balloon response
125
What does radio opaque marker on IABP allow for?
placement confirmation on X-ray
126
The end of the balloon should be just distal to the takeoff of the ____.
left subclavian artery.
*Tip approximately 1-2cm below the origin of the left subclavian artery and above the renal arteries.*
127
Position should be confirmed by ____ or ____.
fluoroscopy
chest x-ray
*Should be visible in the 2nd or 3rd intercostal space*
128
Event the pump uses to identify the onset of cardiac cycle (systole)
Trigger
129
most common modality used as trigger for IABP
ECG
130
On ECG:
Inflation occurs at ____.
Deflation occurs at ____.
Inflation: end of T-wave
Deflation: beginning of R-wave
131
If arterial pressure waveform is used as IABP trigger,
Inflation occurs at: ____
Deflation occurs at: ____
Inflation: dicrotic notch
Deflation: systolic upstroke
132
What modality is used by IABP during CPB or VFib?
intrinsic set rate
(1:1 - 1:8)
every beat or every 8th beat
133
Normal augmented A-line Waveform with IABP
134
Will MAP decrease or increase with a IABP?
Increase
*Although systolic pressures decrease slightly, diastolic pressure increases significantly.*
135
Diastolic augmentation should be lower/higher than systolic.
higher
136
Early Inflation (before dicrotic notch)
*...if balloon inflates too soon, interrupting the end of systole*
- Increase work of heart (at end systole)
- Aortic Regurgitation (inflation will cause backflow of blood into LV)
- **2nd worst**
137
Late Inflation (after dicrotic notch)
- Heart is not getting enough help during diastole
- decreased Coronary Perfusion
- *NOT making heart work, just less effective*
138
Early Deflation
...while heart is still in diastole
- some help with coronary perfusion, just not optimal
- not making the heart work harder
138
Late Deflation
- **WORST**
- *balloon obstructing systole*
- Significantly Increases work of heart
139
IABP Complications
- **Limb ischemia**
(Thrombosis, Emboli)
- **Local vascular injury**
(Bleeding at insertion site, Groin hematoma, False aneurysm)
- **Aortic perforation and/or dissection**
- Malpositioning causing cerebral, renal, or bowel compromise
- Neurologic complications including paraplegia
- **Heparin induced thrombocytopenia
- Balloon rupture → gas embolus
Infection**
140
Weaning from IABP
- Timing of weaning
(Patient should be stable for 24-48 hours)
- Decreasing inotropic support
- Decrease augmentation slowly
- Decreasing pump ratio
(From 1:1 to 1:2 or 1:3)
- Monitor patient closely
(If patient becomes unstable, weaning should be immediately discontinued)
141
# Final Points IABP
The primary goal of IABP treatment is to increase ____ and decrease ____.
myocardial O2 supply
myocardial O2 demand
142
# Final Points IABP
Decreased urine output after insertion may occur because of balloon positioning obstructing ____.
renal artery
143
Hemolysis from mechanical damage to RBCs can reduce Hct by up to ____%
5%
144
IABP is ___-genic → always anticoagulant the pt.
thrombo
145
# Final Points IABP
T/F: Never switch the balloon off while in use
True
