Pace Makers Flashcards
2 ways in which diseased heart tissue blocks normal impulses.
- Prevent impulse generation in SA node
- Inhibit impulse conduction
2 components of pacemaker?
- Implantable pulse generator
- Lead wires
Cathode is the _______ electrode and Anode is the _______ electrode.
- Negative
- Positive
Describe passive lead fixation?
-Tines lodge in the trabeculae (fibrous meshwork) of heart
Describe active fixation of leads?
-Helix (screw) extends into endocardial tissue
What is the most common frequency associated with pacemaker interference?
-50-60hz
EMI may result in what 3 things?
- Oversensing
- Mode changing
- Reprogramming
When will rates accelerate as a result of EMI?
-If sensed as P waves in dual chamber system
When will rates be inhibited as a result of EMI?
- Single chamber system
- or ventricular lead in dual chamber
What is noise reversion?
- refractory sensing will cause pacing at lower rates.
- sensed “noise” will initiate new refractory period
EMI may lead to _________ ___________ of pacing parameters and device may revert to ______ on ______ mode.
- Inadvertent Reprogramming
- Power on Reset
7 Sources of EMI in hospitals.
and which is most common?
- Electrocautery (most common)
- Lithotripsy
- Defibrilation
- radiation
- RF ablation
- TENS unit
- MRI
What 4 things can occur with electrocautery EMI?
- Oversensing
- Undersensing
- Power in reset
- Loss of output
6 precautions for electrocautery EMI?
- Reprogram to VOO/DOO
- Place Magnet
- Grounding plate
- 1 sec bursts every 10 secs
- Bipolar electrocautery
- Keep positioned so that current does not intersect the PM
How to avoid pacemaker damage with defibrillation.
Position paddles as far away from pacemaker as possible.
MRI with pacemaker potential outcomes.
- High pacing
- asynchronous pacing
How to avoid MRI pacemaker problems?
- Program output low enough for non capture
- ODO/OVO mpde
Lithotripsy pacemaker precautions.
- VVI/VOO mode
- Focal point >6 inches from pacemaker
Lithotripsy problems w/ dual chamber? adaptive?
- Inhibits ventricular pacing
- High pacing, piezoelectric crystal damage
What type of radiation and for what cancers can cause pacemaker damage? RADs should be kept to what?
- Ionizing radiation
- Breast and lung cancer
- <500
Describe rate response pacing.
-Give patients ability to vary HR when SA node cannot provide appropriate rate.
When is rate responsive pacing indicated?
- Chronotropically incompetent (HR cant reach appropriate levels)
- Afib w/ slow ventricular response
SV x HR = ?
Cardiac output
_________ reserves can account for increases in CO up to 50%.
-Stroke volume
What reserves can triple CO in response to metabolic demands?
HR
2 types of rate responsive sensors
- Detect movement and increase HR according to activity
- Minute ventilation sensors detect changes in RR and tidal volume
Class 1 (Strongest evidence that therapy is beneficial) indications for pacemaker.
- Sinus node dysfunction w/ brady
- Symptomatic chronotropic incomptence
Class 2A (Evidence in favor) indications for pacemaker
-Symptomatic patients w/ SA node dysfunction w/o association between symptoms and brady
Class 2B (less well established) indications for pacemaker
-Chronic HR <30
Class 3 (Therapy is unnecessary) indications for pacemaker
-Asymptomatic sinus node dysfunction
Describe 1st degree block
-Prolonged P-R interval (no drop)
Describe 2nd degree Mobitz type 1
-P-R that lengthens then drops
Describe 2nd degree Mobitz type 2
- Regularly dropped ventricular beats
- 2:1 block (2 P’s for 1 QRS)
Describe 3rd degree heart block
- Complete heart block
- Atria and ventricle contract independent of each other
6 pacemaker indications.
- AV block
- Sinus node dysfunction
- Bi/trifasciular block
- Hypersensitive carotid sinus
- Vaso-vagal syncope
- Cardiac transplant
What is the 1st letter of NBG code?
-Chamber paced
What is the 2nd letter of NBG code?
Chamber sensed
What is the 3rd letter of NBG code?
Response to sensing
What are the 5 setting for NBG code 1 and 2?
V=Ventricle A=Atrium D=Dual O=None S=Single
What is NBG setting for the 3rd letter (response to sensing)
T=triggered
I=Inhibited
D=Dual
O=None
NBG code 4 settings
P=Simple programmable M=Multi programmable C=Communicating R=Rate modulating O=None
NBG code 5 (antitachy) settings
P=Pace
S=Shock
D=Dual
O=None
Name 6 class 1 sinus node dysfunctions
- Sinus Brady
- Sinus arrest
- Sinus pause
- Brady - tachy syndrome
- Atrial flutter
- Chronotropic incompentence
indications for ICD
- Cardiac arrest
- VT (sustained & non-sustained)
- Syncope
- Ejection fraction <30
_______ and _______ pose no threat to pacemakers or ICDs
- Microwaves
- Ultrasound
What will a magnet place over a pacemaker do?
-Convert to VVI
What will a magnet placed over a AICD do?
- Suspend EMI detection
- Should be removed should VF occur
