Homework

Question 1

Define Threshold

Answer 1

the minimum amplitude and duration required to generate the self-propagation wave

Question 2

Where are the anode and cathode located in a bipolar system?

Answer 2

inside the heart

Question 3

Where are the cathode and anode in a unipolar system?

Answer 3

cathode in the heart

anode outside the heart

Question 4

Which stimulation has the larger spike?

Answer 4

unipolar

Question 5

What is the equation for Ohm’s law?

Answer 5

V = IR

Question 6

Define stimulation threshold

Answer 6

Minimum stimulus and duration necessary to initiate depolarization wavefront

Question 7

What two conditions must be met for a pacing stimulus to “capture”?

Answer 7

threshold: proper amplitude and duration

Question 8

What is the programmed margin of safety for voltage?

Answer 8

2x voltage threshold

Question 9

What is the programmed margin of safety for pulse duration?

Answer 9

3x duration threshold

Question 10

What do low impedance measurements reflect?

Answer 10

failure in lead conductor insulation

Question 11

what do high impedance values suggest?

Answer 11

conduction fracture or loose set-screw at connector

Question 12

What steroid is used in pacemaker leads?

Answer 12

DSP, to reduce inflammation

Question 13

What is the largest single entity inside the pulse generator?

Answer 13

battery

Question 14

What is “crosstalk”?

Answer 14

atrial channel thinks that far-field ventricle activity is intrinsic atrial activity

Question 15

Name the two output parameters

Answer 15

Voltage

time

Question 16

How much high can chronic thresholds be compared to acute thresholds?

Answer 16

2-5 times higher

Question 17

What should the sensitivity margin be at implant?

Answer 17

2

Question 18

Explain noise reversion

Answer 18

A change in pacing mode, typically to async pacing at the programmed rate

Question 19

What is the most advanced form of pacing system currently available?

Answer 19

DDDRD

Question 20

What are the five components of pacing leads?

Answer 20

electrodes
conductors
insulation
connector pin
fixation mechanism

Question 21

What type of lead is more difficult to extract?

Answer 21

passive fixation - tends to be more scar

Question 22

What is IS-1?

Answer 22

Industry Standard

Question 23

What is the power source of all present generators?

Answer 23

Lithium powered battery

Question 24

What does a magnet do to the reed switch?

Answer 24

closes the reed switch, which puts the pacemaker into OO mode

Question 25

Which two sensors are “blended”?

Answer 25

Minute-ventilation and activity sensor

Question 26

Define AAI mode

Answer 26

no intrinsic A is sensed the pacemaker will pace in the A; when A is sensed the pacemaker inhibits

Question 27

What three names might the “pacing rate” also be called?

Answer 27

automatic interval
basic interval
pacing rate
demand interval

Question 28

How is the pacing interval’s time defined?

Answer 28

time period in milliseconds between two consecutive paced event in the same chamber

Question 29

why would a RV paced beat have a LBBB morphology?

Answer 29

it goes from RV to LV like in LBBB

Question 30

Define pseudofusion beat

Answer 30

pacemaker output falls simultaneously on an intrinsic event but the intrinsic comes slightly before

Question 31

Define fusion beat

Answer 31

output pulse which contributes to an intrinsic beat