CCDSIBHREExamQuestions&Answers2025/2026

CCDSIBHREExamQuestions&Answers2025/2
026

1.RheobaseAnswer>thelowestpointonastrengthdurationcurveataninfinitdurat
ion elylongpulse



2. ChronaxietimeAnswer>thepulsewidthattwicetherheobasevalue.Itapproximatest
hemostefficientstimulationpulseduration

3. Charge(formula)Answer>Charge=I(current)xT(time)

4. Furman'sformulaAnswer>Energy(microjoules)=I(current)xV(voltage)xT(pulsew
th)

5. OhmslawformulaAnswer>Voltage(electromotiveforce)=I(current/flowofelectr
ons)xR(resistancetocurrentflowinohms)

6. FunctionalRefractoryPeriodAnswer>thecouplingintervalwhichfirstresultsiname
a-surabledegreeofdelayinimpulseconduction

7. EffectiveRefractoryPeriodAnswer>thelongestcouplingintervaltobeassociatedwit
hblock

8. DeviceswithNOinteractionwithpacersAnswer>1.microwaveoven,2.CTscan/Ultr
a-sound3.X-rays(diagnostic)

9. Devicesthatcausetransientor1beatinhibitionAnswer>1.EAS2.Cellphones3.Arc
Welding4.airportmetaldetector5.TENS6.Electricappliancessuchaselectricblanket&po
wertools

10. DevicesthatmaydamagethepacemakerAnswer>1.MRI2.Defibrillator3.Cardiov
er-sion4.Cautery/RFAblation5.RadiationTherapy

11. ResistanceinSeriesAnswer>Seriesmeansthebeginningofoneresistanceiscon-
nectedtoanother

SumtheresistancesAnswer>R1+R2=totalresistance.EXAnswer>ALEADFRACTURE(frac
uresINCREASEimpedance)
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12. ResistanceinParallelAnswer>Parallelmeansalltheresistancesareconnectedtothe
samepoint.

(R1xR2)/(R1+R2)=totalresistance

EXAnswer>LEADINSULATIONDEFECTS(insulationdefectsDECREASEimpedance)

13. Permanentpacemakersareconstantvoltageorconstantcurrent?Answer>A
LLpermanentpacemakersareconstantvoltagedevices.

SOMEtemppacemakersareconstantvoltage,mostareconstantcurrent.

14. LOADAnswer>Loadreferstoimpedance(orresistance)appliedtoacircuit.

AsystemwithaSMALLload(lowimpedance)appliedtothecircuitissaidtobeaconstantcurr
ntdevice




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AsystemwithLARGEloadissaidtobeaconstantvoltagedevice

15. GuidelinesforPermanentPacingAnswer>1.Patientissymptomatic

2. Theheartrateislessthan40bpm

3. Asystoleofgreaterthan3secondsisdocumented

NOTEAnswer>Ptmaybeasymptomaticwith2or3

16. SlewRateAnswer>Slewrate=peakslopeofanelectrogram

slewrate=changeinvoltage/changeintime

17. NormalslewrateinatriumAnswer>>.3V/s

18. NormalslewrateinventricleAnswer>>.5V/s

19. SteroidusedinelectrodesAnswer>dexamethasonesodiumphosphateinthesilicon
ecore(acorticosteriod)

20. Steroid-
ElutingElectrodesAnswer>1.Theacutethresholdisrelativelyflatcomparedtonon-
steroidelectrodes

2.Theinitialcapturethresholdissimilartonon-steroidleads

21. SiliconeRubberleadinsulationProsAnswer>1.Caneasilyberepaired

2. Flexible

3. Provenperformancehistory

4. Easytomake

22. SiliconeRubberleadinsulationconsAnswer>1.highfrictioncoefficient

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2. Absorbslipids

3. Morethrombogenicandfibrotic

4. Cutseasily

5. Tearseasilyifsuturetiedtootightly

6. Largediameter

23. Polyurethane80AAnswer>BAD

24. Polyurethane55DAnswer>GOOD

25. polyurethaneleadinsulationprosAnswer>1.relativelynonthrombogenic/fibrotic

2. thinwalls

3. hightearfriction

4. resistscutting

5. lowfrictioncoefficient

26. polyurethaneleadinsulationconsAnswer>1.cannotberepaired

2. relativelystiff

3. hardtomake

27. PacemakerSyndromeCausesAnswer>1.LossofAVsynchrony

2. Sustainedretrogradeconduction




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