PM/ICDs Flashcards
Two most common indications for PM insertion?
SA node dysfunction and AV block
Indications for PM insertion?
correlation of at least one symptom and an arrythmia
What is HTN Carotid Sinus Syndrome?
recurrent syncopal episodes associated with carotid stimulation
What is chronotropic competence/incompetence?
instead of a fast rise in hr when they start exercising, followed by stable hr during exercise, and slow drop off when they’re done exercising, these people have a very slow increase in hr, not stable during exercise, when finished exercising is quick drop off. main symptom is exercise intolerance
Which type of heart block warrants a PM even if the patient doesnt have symptoms?
2nd degree AV block Type II
What are 3 lifestyle assessment tests for patient needing a PM?
graded treadmill test, holter monitor, or EP studies in cath lab
Does every PM have a reed switch?
yes
What are the components of a PM?
battery, connection outlet, electrical circuit, lead (insulated wire), electrode tip
What does putting a magnet on a PM do to the reed switch?
closes reed switch and pm switches to diff mode and paces at fixed rate.
What is a reed switch?
an electrical switch operated by an applied magnetic field
PMs use a 5 letter system for PM coding. What does each of the 5 letters represent?
1- chambers paced II- chambers sensed III- response to sensed event IV- programmability features V- antitachyarrhythmic functions
PM codes: t stands for?
trigger pacing
PM codes: i stands for
inhibit pacing
PM codes: p stands for
programmability of rate and/or output
PM codes: c stands for
communicating
PM codes: o stands for
none
This part of the PM includes the energy source and electrical circuit for pacing and sensing functions?
pulse generator
This part of the PM is the insulated wires that come from the pulse generator to the electrode?
leads
This part of the PM is the exposed metal end of the lead that comes in contact with the epicardium or endocardium?
electrode
Disadvantage to using unipolar lead over bipolar lead?
unipolar lead is more likely to pick up extra noise
How does unipolar lead pacing work?
there is a negative lead, or cathode, from which current flows to the heart and stimulates the heart and then returns to the + pole on the casing of the generator via the myocardium and adjacent tissue to complete the circuit
How does bipolar lead pacing work?
2 separate electrodes: + and _ (anode and cathode) and both located in chamber being paced. electrodes placed very close so signal is crisp and they are much less likely to pick up extra noise
This type of pacing is also known as transvenous pacing. The lead system is placed thru vein in to RA or RV. Typically use right SC vein
endocardial pacing
Minimum amt of energy needed to consistently cause depol/contraction on heart?
pacing threshold
What happens to the PM threshold in the first month after PM implantation?
the pacing threshold increases
Measure of minimum voltage of intrinsic r wave necessary to activate sensing circuit of pulse generator and thus inhibit pacing circuit?
r wave sensitivity
If PM resistance suddenly changes, what does it usually indicate?
usually indicates a problem in the lead system
What does very high resistance usually indicate?
conductor fracture or lousy connect to PM
What does very low resistance usually indicate?
broken wire and insulation failure
This is the diff between intrinsic hr at which pacing begins and pacing?
hysteresis
What happens in a runaway PM?
acceleration in paced rates due to aging of PM and or damage produced by leakage of tissue fluids in to PM
How do you treat a runaway pacemaker?
NOT with drugs or cardioversion; change PM to asynchronous mode or reprogram to lower outputs. if pt is HD unstable, use a temporary PM until the pulse generator can be changed
Sx associated with needing a PM?
syncope, dizziness, CHF, confusion, seizures, chest pain, palpitations, fatigue, SOB, chest tightness, exercise intolerance
Examples of sinoatrial dysfunction?
sinus brady, sinus arrest, sinus pause, tachy/brady syndrome, atrial flutter, atrial fibrillation, chronotropic incompetence
Is a PM indicated for first degree AVB?
rarely
Is a PM indicated for 2nd degree Type I AVB?
only when symptoms are present
Is a PM indicated for 3rd degree block?
yes, usually
Patient assessment for PM?
H&P, EKG, lifestyle assessment: holter monitor, EP studies, graded treadmill
Types of pacemakers?
unipolar vs bipolar and fixed rate vs responsive
In the PM system, what is resistance?
sum of resistance in lead and resistance thru pt’s tissue and polarization that takes place when voltage and current delivered in to tissues
