CCDS IBHRE ACTUAL EXAM LATEST VERSION
2024/2025\\ WITH QUESTIONS AND CORRECT
ANSWERS GRADE A
Rheobase - CORRECT ANSWER ; the lowest point on a strength duration
curve at an infinitely long pulse duration
Chronaxie time - CORRECT ANSWER ; the pulse width at twice the
rheobase value. It approximates the most efficient stimulation pulse
duration
Charge (formula) - CORRECT ANSWER ; Charge= I(current) x T(time)
Furman's formula - CORRECT ANSWER ; Energy(microjoules)=
I(current)xV(voltage)xT(pulse width)
Ohms law formula - CORRECT ANSWER ; Voltage(electromotive
force)= I(current/flow of electrons) x R(resistance to current flow in
ohms)
Functional Refractory Period - CORRECT ANSWER ; the coupling
interval which first results in a measurable degree of delay in impulse
conduction
,Effective Refractory Period - CORRECT ANSWER ; the longest coupling
interval to be associated with block
Devices with NO interaction with pacers - CORRECT ANSWER ; 1.
microwave oven, 2. CT scan/Ultrasound 3. X-rays (diagnostic)
Devices that cause transient or 1 beat inhibition - CORRECT ANSWER ;
1. EAS 2. Cellphones 3. Arc Welding 4. airport metal detector 5. TENS
6. Electric appliances such as electric blanket & power tools
Devices that may damage the pacemaker - CORRECT ANSWER ; 1. MRI
2. Defibrillator 3. Cardioversion 4. Cautery/RF Ablation 5. Radiation
Therapy
Resistance in Series - CORRECT 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)
Resistance in Parallel - CORRECT 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)
Permanent pacemakers are constant voltage or constant current? -
CORRECT ANSWER ; ALL permanent pacemakers are constant voltage
devices.
SOME temp pacemakers are constant voltage, most are constant current.
LOAD - CORRECT 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
Guidelines for Permanent Pacing - CORRECT 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
, Slew Rate - CORRECT ANSWER ; Slew rate = peak slope of an
electrogram
slew rate= change in voltage/ change in time
Normal slew rate in atrium - CORRECT ANSWER ; >.3 V/s
Normal slew rate in ventricle - CORRECT ANSWER ; >.5V/s
Steroid used in electrodes - CORRECT ANSWER ; dexamethasone
sodium phosphate in the silicone core(a corticosteriod)
Steroid-Eluting Electrodes - CORRECT ANSWER ; 1. The acute
threshold is relatively flat compared to non-steroid electrodes
2. The initial capture threshold is similar to non-steroid leads
Silicone Rubber lead insulation Pros - CORRECT ANSWER ; 1. Can
easily be repaired
2. Flexible
3. Proven performance history
4. Easy to make
Silicone Rubber lead insulation cons - CORRECT ANSWER ; 1. high
friction coefficient
2. Absorbs lipids
2024/2025\\ WITH QUESTIONS AND CORRECT
ANSWERS GRADE A
Rheobase - CORRECT ANSWER ; the lowest point on a strength duration
curve at an infinitely long pulse duration
Chronaxie time - CORRECT ANSWER ; the pulse width at twice the
rheobase value. It approximates the most efficient stimulation pulse
duration
Charge (formula) - CORRECT ANSWER ; Charge= I(current) x T(time)
Furman's formula - CORRECT ANSWER ; Energy(microjoules)=
I(current)xV(voltage)xT(pulse width)
Ohms law formula - CORRECT ANSWER ; Voltage(electromotive
force)= I(current/flow of electrons) x R(resistance to current flow in
ohms)
Functional Refractory Period - CORRECT ANSWER ; the coupling
interval which first results in a measurable degree of delay in impulse
conduction
,Effective Refractory Period - CORRECT ANSWER ; the longest coupling
interval to be associated with block
Devices with NO interaction with pacers - CORRECT ANSWER ; 1.
microwave oven, 2. CT scan/Ultrasound 3. X-rays (diagnostic)
Devices that cause transient or 1 beat inhibition - CORRECT ANSWER ;
1. EAS 2. Cellphones 3. Arc Welding 4. airport metal detector 5. TENS
6. Electric appliances such as electric blanket & power tools
Devices that may damage the pacemaker - CORRECT ANSWER ; 1. MRI
2. Defibrillator 3. Cardioversion 4. Cautery/RF Ablation 5. Radiation
Therapy
Resistance in Series - CORRECT 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)
Resistance in Parallel - CORRECT 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)
Permanent pacemakers are constant voltage or constant current? -
CORRECT ANSWER ; ALL permanent pacemakers are constant voltage
devices.
SOME temp pacemakers are constant voltage, most are constant current.
LOAD - CORRECT 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
Guidelines for Permanent Pacing - CORRECT 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
, Slew Rate - CORRECT ANSWER ; Slew rate = peak slope of an
electrogram
slew rate= change in voltage/ change in time
Normal slew rate in atrium - CORRECT ANSWER ; >.3 V/s
Normal slew rate in ventricle - CORRECT ANSWER ; >.5V/s
Steroid used in electrodes - CORRECT ANSWER ; dexamethasone
sodium phosphate in the silicone core(a corticosteriod)
Steroid-Eluting Electrodes - CORRECT ANSWER ; 1. The acute
threshold is relatively flat compared to non-steroid electrodes
2. The initial capture threshold is similar to non-steroid leads
Silicone Rubber lead insulation Pros - CORRECT ANSWER ; 1. Can
easily be repaired
2. Flexible
3. Proven performance history
4. Easy to make
Silicone Rubber lead insulation cons - CORRECT ANSWER ; 1. high
friction coefficient
2. Absorbs lipids
