CCDS IBHRE
Study online at https://quizlet.com/_6qkqt3
1. Rheobase: the lowest point on a strength duration curve at an infinit ely long pulse
duration
2. Chronaxie time: the pulse width at twice the rheobase value. It approximates the
most efficient stimulation pulse duration
3. Charge (formula): Charge= I(current) x T(time)
4. Furman's formula: Energy(microjoules)= I(current)xV(voltage)xT(pulse width)
5. Ohms law formula: Voltage(electromotive force)= I(current/flow of electrons) x
R(resistance to current flow in ohms)
6. Functional Refractory Period: the coupling interval which first results in a mea-
surable degree of delay in impulse conduction
7. Effective Refractory Period: the longest coupling interval to be associated with
block
8. Devices with NO interaction with pacers: 1. microwave oven, 2. CT scan/Ultra-
sound 3. X-rays (diagnostic)
9. Devices that cause transient or 1 beat inhibition: 1. EAS 2. Cellphones 3. Arc
Welding 4. airport metal detector 5. TENS 6. Electric appliances such as electric
blanket & power tools
10. Devices that may damage the pacemaker: 1. MRI 2. Defibrillator 3. Cardiover-
sion 4. Cautery/RF Ablation 5. Radiation Therapy
11. Resistance in Series: Series means the beginning of one resistance is con-
nected to another
Sum the resistances: R1+R2= total resistance. EX: A LEAD FRACTURE (fractures
INCREASE impedance)
12. Resistance in Parallel: Parallel means all the resistances are connected to the
same point.
(R1xR2)/(R1+R2)= total resistance
EX: LEAD INSULATION DEFECTS (insulation defects DECREASE impedance)
13. Permanent pacemakers are constant voltage or constant current?: ALL
permanent pacemakers are constant voltage devices.
SOME temp pacemakers are constant voltage, most are constant current.
14. LOAD: Load refers to impedance (or resistance) applied to a circuit.
A system with a SMALL load (low impedance) applied to the circuit is said to be a
constant current device
, CCDS IBHRE
Study online at https://quizlet.com/_6qkqt3
A system with LARGE load is said to be a constant voltage device
15. Guidelines for Permanent Pacing: 1. Patient is symptomatic
2. The heart rate is less than 40 bpm
3. Asystole of greater than 3 seconds is documented
NOTE: Pt may be asymptomatic with 2 or 3
16. Slew Rate: Slew rate = peak slope of an electrogram
slew rate= change in voltage/ change in time
17. Normal slew rate in atrium: >.3 V/s
18. Normal slew rate in ventricle: >.5V/s
19. Steroid used in electrodes: dexamethasone sodium phosphate in the silicone
core(a corticosteriod)
20. Steroid-Eluting Electrodes: 1. The acute threshold is relatively flat compared
to non-steroid electrodes
2. The initial capture threshold is similar to non-steroid leads
21. Silicone Rubber lead insulation Pros: 1. Can easily be repaired
2. Flexible
3. Proven performance history
4. Easy to make
22. Silicone Rubber lead insulation cons: 1. high friction coefficient
2. Absorbs lipids
3. More thrombogenic and fibrotic
4. Cuts easily
5. Tears easily if suture tied too tightly
6. Large diameter
23. Polyurethane 80A: BAD
24. Polyurethane 55D: GOOD
25. polyurethane lead insulation pros: 1. relatively nonthrombogenic/fibrotic
2. thin walls
3. high tear friction
4. resists cutting
5. low friction coefficient
26. polyurethane lead insulation cons: 1. cannot be repaired
2. relatively stiff
3. hard to make
27. Pacemaker Syndrome Causes: 1. Loss of AV synchrony
2. Sustained retrograde conduction
, CCDS IBHRE
Study online at https://quizlet.com/_6qkqt3
3. A single ventricular rate when rate modulation is required for exercise
Approx 25% of patients only paced from the ventricle may have some level of severity
related to pacemaker syndrome
28. Pacemaker syndrome diagnosis: 1. Observe fluctuation in the peripheral
blood pressure
2. Cannon "A" wave in the neck
3. History alone
29. Pacemaker syndrome management: Restore AV synchrony
in ventricular only PM -->lower the pacing rate to minimize ventricular only pacing
DO NOT increase the pacing rate
30. Fallback: 1. Decouples atrial & ventricular events at the upper rate limit
2. The ventricular inhibited pacing rate then gradually decrements to a programmed
lower or "fallback" rate over a programmed duration
3. When the fallback rate is reached, atrial synchrony is restored
31. Rate smoothing: 1. Eliminated large cycle to cycle variations by preventing
paced rate from changing more than a certain percentage (3%, 6%, 12%, etc) from
one V-V interval to the next
2. Eliminates large fluctuations in rate during fixed-ratio or psuedo-Wenckebach
block
FOUND IN GDT devices
32. sensor upper rate behavior: if the sinus rate is faster than the sensor indicated
rate, P synchronous pacing occurs
if the sensor indicated rate is faster, AV pacing at the sensor indicated rate occurs
mixed scenario: when the device is sensor driven AV pacing for a few cycles and a
sinus rate sudden emerges faster than the sensor indicated rate. The sensor driven
atrial output will be inhibited, a PR interval started, and a ventricular output will occur
at the end of the sensor AV interval. That is, the ventricular rate will be equal to the
sensor indicated rate, but the PV interval may be longer than expected
33. Medtronic Rate Drop Response: 1. Increase in HR (Pacer is programmed to a
top rate)
2. Rise in HR is immediately followed by a fall in HR. (pacer is programmed to a
"bottom" rate
3.The HR drop must be identified, therefore a number of "Width" beats must be
programmed the HR must fall to the bottom rate in fewer than the programmed
"width" beats
4. To confirm the rate drop, a small number of confirmation beats must be pro-
Study online at https://quizlet.com/_6qkqt3
1. Rheobase: the lowest point on a strength duration curve at an infinit ely long pulse
duration
2. Chronaxie time: the pulse width at twice the rheobase value. It approximates the
most efficient stimulation pulse duration
3. Charge (formula): Charge= I(current) x T(time)
4. Furman's formula: Energy(microjoules)= I(current)xV(voltage)xT(pulse width)
5. Ohms law formula: Voltage(electromotive force)= I(current/flow of electrons) x
R(resistance to current flow in ohms)
6. Functional Refractory Period: the coupling interval which first results in a mea-
surable degree of delay in impulse conduction
7. Effective Refractory Period: the longest coupling interval to be associated with
block
8. Devices with NO interaction with pacers: 1. microwave oven, 2. CT scan/Ultra-
sound 3. X-rays (diagnostic)
9. Devices that cause transient or 1 beat inhibition: 1. EAS 2. Cellphones 3. Arc
Welding 4. airport metal detector 5. TENS 6. Electric appliances such as electric
blanket & power tools
10. Devices that may damage the pacemaker: 1. MRI 2. Defibrillator 3. Cardiover-
sion 4. Cautery/RF Ablation 5. Radiation Therapy
11. Resistance in Series: Series means the beginning of one resistance is con-
nected to another
Sum the resistances: R1+R2= total resistance. EX: A LEAD FRACTURE (fractures
INCREASE impedance)
12. Resistance in Parallel: Parallel means all the resistances are connected to the
same point.
(R1xR2)/(R1+R2)= total resistance
EX: LEAD INSULATION DEFECTS (insulation defects DECREASE impedance)
13. Permanent pacemakers are constant voltage or constant current?: ALL
permanent pacemakers are constant voltage devices.
SOME temp pacemakers are constant voltage, most are constant current.
14. LOAD: Load refers to impedance (or resistance) applied to a circuit.
A system with a SMALL load (low impedance) applied to the circuit is said to be a
constant current device
, CCDS IBHRE
Study online at https://quizlet.com/_6qkqt3
A system with LARGE load is said to be a constant voltage device
15. Guidelines for Permanent Pacing: 1. Patient is symptomatic
2. The heart rate is less than 40 bpm
3. Asystole of greater than 3 seconds is documented
NOTE: Pt may be asymptomatic with 2 or 3
16. Slew Rate: Slew rate = peak slope of an electrogram
slew rate= change in voltage/ change in time
17. Normal slew rate in atrium: >.3 V/s
18. Normal slew rate in ventricle: >.5V/s
19. Steroid used in electrodes: dexamethasone sodium phosphate in the silicone
core(a corticosteriod)
20. Steroid-Eluting Electrodes: 1. The acute threshold is relatively flat compared
to non-steroid electrodes
2. The initial capture threshold is similar to non-steroid leads
21. Silicone Rubber lead insulation Pros: 1. Can easily be repaired
2. Flexible
3. Proven performance history
4. Easy to make
22. Silicone Rubber lead insulation cons: 1. high friction coefficient
2. Absorbs lipids
3. More thrombogenic and fibrotic
4. Cuts easily
5. Tears easily if suture tied too tightly
6. Large diameter
23. Polyurethane 80A: BAD
24. Polyurethane 55D: GOOD
25. polyurethane lead insulation pros: 1. relatively nonthrombogenic/fibrotic
2. thin walls
3. high tear friction
4. resists cutting
5. low friction coefficient
26. polyurethane lead insulation cons: 1. cannot be repaired
2. relatively stiff
3. hard to make
27. Pacemaker Syndrome Causes: 1. Loss of AV synchrony
2. Sustained retrograde conduction
, CCDS IBHRE
Study online at https://quizlet.com/_6qkqt3
3. A single ventricular rate when rate modulation is required for exercise
Approx 25% of patients only paced from the ventricle may have some level of severity
related to pacemaker syndrome
28. Pacemaker syndrome diagnosis: 1. Observe fluctuation in the peripheral
blood pressure
2. Cannon "A" wave in the neck
3. History alone
29. Pacemaker syndrome management: Restore AV synchrony
in ventricular only PM -->lower the pacing rate to minimize ventricular only pacing
DO NOT increase the pacing rate
30. Fallback: 1. Decouples atrial & ventricular events at the upper rate limit
2. The ventricular inhibited pacing rate then gradually decrements to a programmed
lower or "fallback" rate over a programmed duration
3. When the fallback rate is reached, atrial synchrony is restored
31. Rate smoothing: 1. Eliminated large cycle to cycle variations by preventing
paced rate from changing more than a certain percentage (3%, 6%, 12%, etc) from
one V-V interval to the next
2. Eliminates large fluctuations in rate during fixed-ratio or psuedo-Wenckebach
block
FOUND IN GDT devices
32. sensor upper rate behavior: if the sinus rate is faster than the sensor indicated
rate, P synchronous pacing occurs
if the sensor indicated rate is faster, AV pacing at the sensor indicated rate occurs
mixed scenario: when the device is sensor driven AV pacing for a few cycles and a
sinus rate sudden emerges faster than the sensor indicated rate. The sensor driven
atrial output will be inhibited, a PR interval started, and a ventricular output will occur
at the end of the sensor AV interval. That is, the ventricular rate will be equal to the
sensor indicated rate, but the PV interval may be longer than expected
33. Medtronic Rate Drop Response: 1. Increase in HR (Pacer is programmed to a
top rate)
2. Rise in HR is immediately followed by a fall in HR. (pacer is programmed to a
"bottom" rate
3.The HR drop must be identified, therefore a number of "Width" beats must be
programmed the HR must fall to the bottom rate in fewer than the programmed
"width" beats
4. To confirm the rate drop, a small number of confirmation beats must be pro-
