CCDS IBHRE
Question 1.
Rheobase
ANSWER
the lowest point on a strength duration curve at an infinitely long pulse duration
Question 2.
Chronaxie time
ANSWER
the pulse width at twice the rheobase value. It approximates the most efficient stimulation pulse duration
Question 3.
Charge (formula)
ANSWER
Charge= I(current) x T(time)
Question 4.
Furman's formula
ANSWER
Energy(microjoules)= I(current)xV(voltage )xT(pulse width)
Question 5.
Ohms law formula
ANSWER
Voltage(electromotive force)= I(current/flow of electrons) x R(resistance to current flow in ohms)
Question 6.
Functional Refractory Period
ANSWER
the coupling interval which first results in a measurable degree of delay in impulse conduction
Question 7.
Effective Refractory Period
ANSWER
the longest coupling interval to be associated with block
, Question 8.
Devices with NO interaction with pacers
ANSWER
1. microwave oven, 2. CT scan/Ultrasound 3. X-rays (diagnostic)
Question 9.
Devices that cause transient or 1 beat inhibition
ANSWER
1. EAS 2. Cellphones 3. Arc Welding 4. airport metal detector 5. TENS 6. Electric appliances such as electric blanket & power tools
Question 10.
Devices that may damage the pacemaker
ANSWER
1. MRI 2. Defibrillator 3. Cardioversion 4. Cautery/RF Ablation 5. Radiation Therapy
Question 11.
Resistance in Series
ANSWER
Series means the beginning of one resistance is connected to another Sum the resistances: R1+R2= total resistance. EX: A LEAD FRACTURE (fractures
INCREASE impedance )
Question 12.
Resistance in Parallel
ANSWER
Parallel means all the resistances are connected to the same point. (R1xR2)/(R1+R2)= total resistance EX: LEAD INSULATION DEFECTS (insulation
defects DECREASE impedance)
Question 13.
Permanent pacemakers are constant voltage or constant current?
ANSWER
ALL permanent pacemakers are constant voltage devices. SOME temp pacemakers are constant voltage, most are constant current.
Question 14.
LOAD
ANSWER
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 A system with LARGE load is said to be a constant voltage device
, Question 15.
Guidelines for Permanent Pacing
ANSWER
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
Question 16.
Slew Rate
ANSWER
Slew rate = peak slope of an electrogram slew rate= change in voltage/ change in time
Question 17.
Normal slew rate in atrium
ANSWER
>.3 V/s
Question 18.
Normal slew rate in ventricle
ANSWER
>.5V/s
Question 19.
Steroid used in electrodes
ANSWER
dexamethasone sodium phosphate in the silicone core(a corticosteriod)
Question 20.
Steroid-Eluting Electrodes
ANSWER
1. The acute threshold is relatively flat compared to non-steroid electrodes
2. The initial capture threshold is similar to non-steroid leads
Question 21.
Silicone Rubber lead insulation Pros
ANSWER
1. Can easily be repaired
2. Flexible
3. Proven performance history
4. Easy to make
, Question 22.
Silicone Rubber lead insulation cons
ANSWER
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
Question 23.
Polyurethane 80A
ANSWER
BAD
Question 24.
Polyurethane 55D
ANSWER
GOOD
Question 25.
polyurethane lead insulation pros
ANSWER
1. relatively nonthrombogenic/fibrotic
2. thin walls
3. high tear friction
4. resists cutting
5. low friction coefficient
Question 26.
polyurethane lead insulation cons
ANSWER
1. cannot be repaired
2. relatively stiff
3. hard to make
Question 27.
Pacemaker Syndrome Causes
ANSWER
1. Loss of AV synchrony
2. Sustained retrograde conduction
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
Question 1.
Rheobase
ANSWER
the lowest point on a strength duration curve at an infinitely long pulse duration
Question 2.
Chronaxie time
ANSWER
the pulse width at twice the rheobase value. It approximates the most efficient stimulation pulse duration
Question 3.
Charge (formula)
ANSWER
Charge= I(current) x T(time)
Question 4.
Furman's formula
ANSWER
Energy(microjoules)= I(current)xV(voltage )xT(pulse width)
Question 5.
Ohms law formula
ANSWER
Voltage(electromotive force)= I(current/flow of electrons) x R(resistance to current flow in ohms)
Question 6.
Functional Refractory Period
ANSWER
the coupling interval which first results in a measurable degree of delay in impulse conduction
Question 7.
Effective Refractory Period
ANSWER
the longest coupling interval to be associated with block
, Question 8.
Devices with NO interaction with pacers
ANSWER
1. microwave oven, 2. CT scan/Ultrasound 3. X-rays (diagnostic)
Question 9.
Devices that cause transient or 1 beat inhibition
ANSWER
1. EAS 2. Cellphones 3. Arc Welding 4. airport metal detector 5. TENS 6. Electric appliances such as electric blanket & power tools
Question 10.
Devices that may damage the pacemaker
ANSWER
1. MRI 2. Defibrillator 3. Cardioversion 4. Cautery/RF Ablation 5. Radiation Therapy
Question 11.
Resistance in Series
ANSWER
Series means the beginning of one resistance is connected to another Sum the resistances: R1+R2= total resistance. EX: A LEAD FRACTURE (fractures
INCREASE impedance )
Question 12.
Resistance in Parallel
ANSWER
Parallel means all the resistances are connected to the same point. (R1xR2)/(R1+R2)= total resistance EX: LEAD INSULATION DEFECTS (insulation
defects DECREASE impedance)
Question 13.
Permanent pacemakers are constant voltage or constant current?
ANSWER
ALL permanent pacemakers are constant voltage devices. SOME temp pacemakers are constant voltage, most are constant current.
Question 14.
LOAD
ANSWER
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 A system with LARGE load is said to be a constant voltage device
, Question 15.
Guidelines for Permanent Pacing
ANSWER
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
Question 16.
Slew Rate
ANSWER
Slew rate = peak slope of an electrogram slew rate= change in voltage/ change in time
Question 17.
Normal slew rate in atrium
ANSWER
>.3 V/s
Question 18.
Normal slew rate in ventricle
ANSWER
>.5V/s
Question 19.
Steroid used in electrodes
ANSWER
dexamethasone sodium phosphate in the silicone core(a corticosteriod)
Question 20.
Steroid-Eluting Electrodes
ANSWER
1. The acute threshold is relatively flat compared to non-steroid electrodes
2. The initial capture threshold is similar to non-steroid leads
Question 21.
Silicone Rubber lead insulation Pros
ANSWER
1. Can easily be repaired
2. Flexible
3. Proven performance history
4. Easy to make
, Question 22.
Silicone Rubber lead insulation cons
ANSWER
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
Question 23.
Polyurethane 80A
ANSWER
BAD
Question 24.
Polyurethane 55D
ANSWER
GOOD
Question 25.
polyurethane lead insulation pros
ANSWER
1. relatively nonthrombogenic/fibrotic
2. thin walls
3. high tear friction
4. resists cutting
5. low friction coefficient
Question 26.
polyurethane lead insulation cons
ANSWER
1. cannot be repaired
2. relatively stiff
3. hard to make
Question 27.
Pacemaker Syndrome Causes
ANSWER
1. Loss of AV synchrony
2. Sustained retrograde conduction
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
