CCDS IBHRE
Study online at https://quizlet.com/_h3bzt3
the lowest point on a strength duration
curve at an infinitely long pulse duration
Rheobase
the pulse width at twice the rheobase
Chronaxie time value. It approximates the most efficient
stimulation pulse duration
Charge (formula) Charge= I(current) x T(time)
Energy(microjoules)= I(current)xV(volt-
Furman's formula
age)xT(pulse width)
Voltage(electromotive force)= I(cur-
Ohms law formula rent/flow of electrons) x R(resistance to
current flow in ohms)
the coupling interval which first results in
Functional Refractory Period a measurable degree of delay in impulse
conduction
the longest coupling interval to be asso-
Effective Refractory Period
ciated with block
1. microwave oven, 2. CT scan/Ultra-
Devices with NO interaction with pacers
sound 3. X-rays (diagnostic)
1. EAS 2. Cellphones 3. Arc Welding 4.
Devices that cause transient or 1 beat airport metal detector 5. TENS 6. Elec-
inhibition tric appliances such as electric blanket &
power tools
1. MRI 2. Defibrillator 3. Cardioversion 4.
Devices that may damage the pacemak-
Cautery/RF Ablation 5. Radiation Thera-
er
py
Series means the beginning of one resis-
Resistance in Series tance is connected to another
, CCDS IBHRE
Study online at https://quizlet.com/_h3bzt3
Sum the resistances: R1+R2= total re-
sistance. EX: A LEAD FRACTURE (frac-
tures INCREASE impedance)
Parallel means all the resistances are
connected to the same point.
(R1xR2)/(R1+R2)= total resistance
Resistance in Parallel
EX: LEAD INSULATION DEFECTS (in-
sulation defects DECREASE imped-
ance)
ALL permanent pacemakers are con-
stant voltage devices.
Permanent pacemakers are constant
voltage or constant current?
SOME temp pacemakers are constant
voltage, most are constant current.
Load refers to impedance (or resistance)
applied to a circuit.
A system with a SMALL load (low imped-
LOAD ance) applied to the circuit is said to be
a constant current device
A system with LARGE load is said to be
a constant voltage device
1. Patient is symptomatic
2. The heart rate is less than 40 bpm
3. Asystole of greater than 3 seconds is
Guidelines for Permanent Pacing documented
NOTE: Pt may be asymptomatic with 2 or
3
Slew rate = peak slope of an electrogram
Slew Rate
slew rate= change in voltage/ change in
time
Normal slew rate in atrium >.3 V/s
, CCDS IBHRE
Study online at https://quizlet.com/_h3bzt3
Normal slew rate in ventricle >.5V/s
dexamethasone sodium phosphate in
Steroid used in electrodes
the silicone core(a corticosteriod)
1. The acute threshold is relatively flat
compared to non-steroid electrodes
Steroid-Eluting Electrodes
2. The initial capture threshold is similar
to non-steroid leads
1. Can easily be repaired
2. Flexible
Silicone Rubber lead insulation Pros
3. Proven performance history
4. Easy to make
1. high friction coefficient
2. Absorbs lipids
3. More thrombogenic and fibrotic
Silicone Rubber lead insulation cons
4. Cuts easily
5. Tears easily if suture tied too tightly
6. Large diameter
Polyurethane 80A BAD
Polyurethane 55D GOOD
1. relatively nonthrombogenic/fibrotic
2. thin walls
polyurethane lead insulation pros 3. high tear friction
4. resists cutting
5. low friction coefficient
1. cannot be repaired
polyurethane lead insulation cons 2. relatively stiff
3. hard to make
1. Loss of AV synchrony
2. Sustained retrograde conduction
3. A single ventricular rate when rate
modulation is required for exercise
Pacemaker Syndrome Causes
Approx 25% of patients only paced from
the ventricle may have some level of
severity related to pacemaker syndrome
Pacemaker syndrome diagnosis
, CCDS IBHRE
Study online at https://quizlet.com/_h3bzt3
1. Observe fluctuation in the peripheral
blood pressure
2. Cannon "A" wave in the neck
3. History alone
Restore AV synchrony
in ventricular only PM -->lower the pac-
Pacemaker syndrome management ing rate to minimize ventricular only pac-
ing
DO NOT increase the pacing rate
1. Decouples atrial & ventricular events
at the upper rate limit
2. The ventricular inhibited pacing rate
then gradually decrements to a pro-
Fallback
grammed lower or "fallback" rate over a
programmed duration
3. When the fallback rate is reached, atri-
al synchrony is restored
1. Eliminated large cycle to cycle vari-
ations by preventing paced rate from
changing more than a certain percent-
age (3%, 6%, 12%, etc) from one V-V
interval to the next
Rate smoothing
2. Eliminates large fluctuations in rate
during fixed-ratio or psuedo-Wencke-
bach block
FOUND IN GDT devices
if the sinus rate is faster than the sensor
indicated rate, P synchronous pacing oc-
curs
if the sensor indicated rate is faster, AV
pacing at the sensor indicated rate oc-
sensor upper rate behavior curs
mixed scenario: when the device is sen-
sor driven AV pacing for a few cycles
and a sinus rate sudden emerges faster
than the sensor indicated rate. The sen-
sor driven atrial output will be inhibited,
Study online at https://quizlet.com/_h3bzt3
the lowest point on a strength duration
curve at an infinitely long pulse duration
Rheobase
the pulse width at twice the rheobase
Chronaxie time value. It approximates the most efficient
stimulation pulse duration
Charge (formula) Charge= I(current) x T(time)
Energy(microjoules)= I(current)xV(volt-
Furman's formula
age)xT(pulse width)
Voltage(electromotive force)= I(cur-
Ohms law formula rent/flow of electrons) x R(resistance to
current flow in ohms)
the coupling interval which first results in
Functional Refractory Period a measurable degree of delay in impulse
conduction
the longest coupling interval to be asso-
Effective Refractory Period
ciated with block
1. microwave oven, 2. CT scan/Ultra-
Devices with NO interaction with pacers
sound 3. X-rays (diagnostic)
1. EAS 2. Cellphones 3. Arc Welding 4.
Devices that cause transient or 1 beat airport metal detector 5. TENS 6. Elec-
inhibition tric appliances such as electric blanket &
power tools
1. MRI 2. Defibrillator 3. Cardioversion 4.
Devices that may damage the pacemak-
Cautery/RF Ablation 5. Radiation Thera-
er
py
Series means the beginning of one resis-
Resistance in Series tance is connected to another
, CCDS IBHRE
Study online at https://quizlet.com/_h3bzt3
Sum the resistances: R1+R2= total re-
sistance. EX: A LEAD FRACTURE (frac-
tures INCREASE impedance)
Parallel means all the resistances are
connected to the same point.
(R1xR2)/(R1+R2)= total resistance
Resistance in Parallel
EX: LEAD INSULATION DEFECTS (in-
sulation defects DECREASE imped-
ance)
ALL permanent pacemakers are con-
stant voltage devices.
Permanent pacemakers are constant
voltage or constant current?
SOME temp pacemakers are constant
voltage, most are constant current.
Load refers to impedance (or resistance)
applied to a circuit.
A system with a SMALL load (low imped-
LOAD ance) applied to the circuit is said to be
a constant current device
A system with LARGE load is said to be
a constant voltage device
1. Patient is symptomatic
2. The heart rate is less than 40 bpm
3. Asystole of greater than 3 seconds is
Guidelines for Permanent Pacing documented
NOTE: Pt may be asymptomatic with 2 or
3
Slew rate = peak slope of an electrogram
Slew Rate
slew rate= change in voltage/ change in
time
Normal slew rate in atrium >.3 V/s
, CCDS IBHRE
Study online at https://quizlet.com/_h3bzt3
Normal slew rate in ventricle >.5V/s
dexamethasone sodium phosphate in
Steroid used in electrodes
the silicone core(a corticosteriod)
1. The acute threshold is relatively flat
compared to non-steroid electrodes
Steroid-Eluting Electrodes
2. The initial capture threshold is similar
to non-steroid leads
1. Can easily be repaired
2. Flexible
Silicone Rubber lead insulation Pros
3. Proven performance history
4. Easy to make
1. high friction coefficient
2. Absorbs lipids
3. More thrombogenic and fibrotic
Silicone Rubber lead insulation cons
4. Cuts easily
5. Tears easily if suture tied too tightly
6. Large diameter
Polyurethane 80A BAD
Polyurethane 55D GOOD
1. relatively nonthrombogenic/fibrotic
2. thin walls
polyurethane lead insulation pros 3. high tear friction
4. resists cutting
5. low friction coefficient
1. cannot be repaired
polyurethane lead insulation cons 2. relatively stiff
3. hard to make
1. Loss of AV synchrony
2. Sustained retrograde conduction
3. A single ventricular rate when rate
modulation is required for exercise
Pacemaker Syndrome Causes
Approx 25% of patients only paced from
the ventricle may have some level of
severity related to pacemaker syndrome
Pacemaker syndrome diagnosis
, CCDS IBHRE
Study online at https://quizlet.com/_h3bzt3
1. Observe fluctuation in the peripheral
blood pressure
2. Cannon "A" wave in the neck
3. History alone
Restore AV synchrony
in ventricular only PM -->lower the pac-
Pacemaker syndrome management ing rate to minimize ventricular only pac-
ing
DO NOT increase the pacing rate
1. Decouples atrial & ventricular events
at the upper rate limit
2. The ventricular inhibited pacing rate
then gradually decrements to a pro-
Fallback
grammed lower or "fallback" rate over a
programmed duration
3. When the fallback rate is reached, atri-
al synchrony is restored
1. Eliminated large cycle to cycle vari-
ations by preventing paced rate from
changing more than a certain percent-
age (3%, 6%, 12%, etc) from one V-V
interval to the next
Rate smoothing
2. Eliminates large fluctuations in rate
during fixed-ratio or psuedo-Wencke-
bach block
FOUND IN GDT devices
if the sinus rate is faster than the sensor
indicated rate, P synchronous pacing oc-
curs
if the sensor indicated rate is faster, AV
pacing at the sensor indicated rate oc-
sensor upper rate behavior curs
mixed scenario: when the device is sen-
sor driven AV pacing for a few cycles
and a sinus rate sudden emerges faster
than the sensor indicated rate. The sen-
sor driven atrial output will be inhibited,
