CCDS IBHRE STUDY GUIDE 2026 EXAM QUESTIONS AND
SOLUTIONS RATED A+
✔✔progressive lengthening of PV interval during increase rate - ✔✔pacemaker
wenkebach
sensed p rate is faster than the programmed maximum tracking rate or upper rate
interval
✔✔when should you see pacemaker pacing below base rate? - ✔✔VDD pacing when
AV interval is started when the p wave is sensed and delays the ventricular output
✔✔AR interval - ✔✔begins when the atrial escape interval (AEI) is allowed to "time out"
completely.
An atrial output occurs at the end of the AEI, the AV delay interval is started but is
interrupted by a sensed ventricular channel event(usually an intrinsic R wave)
✔✔Ventricular based timing pacemaker - ✔✔the sensed R wave causes the atrial
escape interval timer to
the next atrial output is based on when and where the R wave is sensed
if the AV delay interval is programmed to 200ms and the sensed R wave occurs at
150ms, the next atrial output will occur 50ms earlier. Hence, the base rate will be faster
✔✔What is the atrial output interval after a PVC if the pacemaker AV delay is set at
200ms and programmed to 60ppm - ✔✔60ppm = 1000ms
1000ms - 200ms AV delay
800ms
✔✔4 states of DDD pacing - ✔✔AV, PV, AR, PR
✔✔when will the PR interval greater than the set AV delay? - ✔✔if the sinus rate is
greater than the upper rate limit of the ventricular pacing
✔✔device longevity formula - ✔✔114 x (Ahr battery capacity)/(current drain in uA) =
Longevity in years
✔✔Ashman's disease - ✔✔occasional wide complex beats during atrial fibrillation with a
right bundle branch morphology are due to aberrant conduction
✔✔Bisping Coaxial lead - ✔✔Bisping - an extendable/retractable helix type lead. The
helix or screw is active
✔✔How can you determine Dextrocardia vs a flipped X ray - ✔✔1. look at the gastric
bubble
,2. look at the "L" marker
✔✔types of pacing leads: unipolar and bipolar - ✔✔1. unipolar - consisting of an outer
insulator and a conductor (the cathode)
2. bipolar - consisting of an outer insulator, an outer conductor (the anode), an inner
insulator, and an inner conductor (the cathode)
✔✔what are the clinical presentations when the outer insulator becomes compromised
in a unipolar system - ✔✔- muscle stimulation
- myopotential inhibition
- myopotential tracking
- reduced lead impedance
- noisy electrogram
- possible attenuation (damping) of the pacemaker artifact
- capture threshold may appear to increase
- ventricular lead insulation defects above the tricuspid valve may result in p wave
sensing
✔✔if the outer insular becomes compromised in a bipolar system, the clinical
presentation will be ... - ✔✔- muscle stimulation
- myopotential inhibition
- myopotential tracking
- reduced lead impedance
- noisy electrogram
- capture threshold may appear to increase
- ventricular lead insulation defects above the tricuspid valve may result in p wave
sensing
****unipolarization of the output spike (larger than normal spike)
****programming the device to unipolar sensing/pacing should eliminate the effects
✔✔if the inner insulator become defective... - ✔✔1. "Make/break" signals may be visible
2. pauses due to detection of the make/break signals
3. Spikes may be attenuated due to short circuiting
4. Capture threshold may appear to rise
✔✔defected ICD leads - ✔✔St. Jude Riata
Medtronic Sprint Fidelis
✔✔Bipolar coaxial lead failure due to which type of insulation? - ✔✔Pellethane 80A
insulation failure - Pacesetter 1016T and 1026T leads
compression by retention sutures over a thin anchoring sleeve
crush injury caused by lead entrapment by the scalenus muscle or costoclavicular
ligament
, ✔✔What would happen when inner coil(Cathode) fractures in bipolar wires? - ✔✔OPEN
CIRCUIT - no pacing will occur, no sensing will occur.
Reprogramming the device to unipolar WILL NOT help
✔✔what happen when the outer coil (anode) fracture in a pacemaker? - ✔✔OPEN
CIRCUIT, however, reprogramming the device to unipolar MAY help since the
pacemaker CAN will be the anode in unipolar mode
✔✔Clinical signs of conductor fracture - ✔✔- rising pacing impedance
- intermittent loss of sensing and/or pacing
- complete failure of sensing and/or pacing
- oversensing (contact potentials)
✔✔make/break signals are due to - ✔✔inner INSULATOR fracture
✔✔Automatic Mode Switching (AMS) - ✔✔When an atrial rate exceeds a predetermined
value, the device switches from a tracking DDD mode to a nontracking VVI mode
At rates between the upper tracking rate and the mode switch rate, the device will
exhibit pacemaker Wenkebach behavior until it reaches the 2:1 block point, it will then
begin 2:1 behavior
✔✔Main purpose of Fallback - ✔✔to avoid rapid and prolonged ventricular pacing
initiated by the sensing of atrial arrhythmias
fallback is used to prevent a sudden rate drop when the atrial rate exceeds the upper
rate limit of the device, it slowly and progressively slowing the ventricular paced rate.
it disassociates the ventricular output from the sinus rate until the sinus rate drops to the
upper ate limit of the fallback rate
✔✔Rate smoothing - ✔✔the pulse generator stores in its memory the most recent RR
interval and does not allow the next RR interval to be less than the preceding RR
interval minus the programmed percentage nor does it allow it to be greater than the
preceding RR interval plus the programmed percentage
✔✔how to calculate the rate smoothing atrial and ventricular window - ✔✔atrial window
= (previous RR interval +/- rate smoothing value) - AV delay
ventricular window = (previous RR interval +/- rate smoothing value)
✔✔downside of rate smoothing function - ✔✔may lead to VA conduction and PMT
because a PAC will lead to delay AV conduction
✔✔Chagas disease - ✔✔the vector is in insect
parasite Trypanosoma cruizi
an acute infection of the heart is the main result, damaging the heart muscle
heart muscle fibers are slowly replaced by scar tissue, thinning the walls of the heart,
severely affecting heart function, and ultimately resulting in death
SOLUTIONS RATED A+
✔✔progressive lengthening of PV interval during increase rate - ✔✔pacemaker
wenkebach
sensed p rate is faster than the programmed maximum tracking rate or upper rate
interval
✔✔when should you see pacemaker pacing below base rate? - ✔✔VDD pacing when
AV interval is started when the p wave is sensed and delays the ventricular output
✔✔AR interval - ✔✔begins when the atrial escape interval (AEI) is allowed to "time out"
completely.
An atrial output occurs at the end of the AEI, the AV delay interval is started but is
interrupted by a sensed ventricular channel event(usually an intrinsic R wave)
✔✔Ventricular based timing pacemaker - ✔✔the sensed R wave causes the atrial
escape interval timer to
the next atrial output is based on when and where the R wave is sensed
if the AV delay interval is programmed to 200ms and the sensed R wave occurs at
150ms, the next atrial output will occur 50ms earlier. Hence, the base rate will be faster
✔✔What is the atrial output interval after a PVC if the pacemaker AV delay is set at
200ms and programmed to 60ppm - ✔✔60ppm = 1000ms
1000ms - 200ms AV delay
800ms
✔✔4 states of DDD pacing - ✔✔AV, PV, AR, PR
✔✔when will the PR interval greater than the set AV delay? - ✔✔if the sinus rate is
greater than the upper rate limit of the ventricular pacing
✔✔device longevity formula - ✔✔114 x (Ahr battery capacity)/(current drain in uA) =
Longevity in years
✔✔Ashman's disease - ✔✔occasional wide complex beats during atrial fibrillation with a
right bundle branch morphology are due to aberrant conduction
✔✔Bisping Coaxial lead - ✔✔Bisping - an extendable/retractable helix type lead. The
helix or screw is active
✔✔How can you determine Dextrocardia vs a flipped X ray - ✔✔1. look at the gastric
bubble
,2. look at the "L" marker
✔✔types of pacing leads: unipolar and bipolar - ✔✔1. unipolar - consisting of an outer
insulator and a conductor (the cathode)
2. bipolar - consisting of an outer insulator, an outer conductor (the anode), an inner
insulator, and an inner conductor (the cathode)
✔✔what are the clinical presentations when the outer insulator becomes compromised
in a unipolar system - ✔✔- muscle stimulation
- myopotential inhibition
- myopotential tracking
- reduced lead impedance
- noisy electrogram
- possible attenuation (damping) of the pacemaker artifact
- capture threshold may appear to increase
- ventricular lead insulation defects above the tricuspid valve may result in p wave
sensing
✔✔if the outer insular becomes compromised in a bipolar system, the clinical
presentation will be ... - ✔✔- muscle stimulation
- myopotential inhibition
- myopotential tracking
- reduced lead impedance
- noisy electrogram
- capture threshold may appear to increase
- ventricular lead insulation defects above the tricuspid valve may result in p wave
sensing
****unipolarization of the output spike (larger than normal spike)
****programming the device to unipolar sensing/pacing should eliminate the effects
✔✔if the inner insulator become defective... - ✔✔1. "Make/break" signals may be visible
2. pauses due to detection of the make/break signals
3. Spikes may be attenuated due to short circuiting
4. Capture threshold may appear to rise
✔✔defected ICD leads - ✔✔St. Jude Riata
Medtronic Sprint Fidelis
✔✔Bipolar coaxial lead failure due to which type of insulation? - ✔✔Pellethane 80A
insulation failure - Pacesetter 1016T and 1026T leads
compression by retention sutures over a thin anchoring sleeve
crush injury caused by lead entrapment by the scalenus muscle or costoclavicular
ligament
, ✔✔What would happen when inner coil(Cathode) fractures in bipolar wires? - ✔✔OPEN
CIRCUIT - no pacing will occur, no sensing will occur.
Reprogramming the device to unipolar WILL NOT help
✔✔what happen when the outer coil (anode) fracture in a pacemaker? - ✔✔OPEN
CIRCUIT, however, reprogramming the device to unipolar MAY help since the
pacemaker CAN will be the anode in unipolar mode
✔✔Clinical signs of conductor fracture - ✔✔- rising pacing impedance
- intermittent loss of sensing and/or pacing
- complete failure of sensing and/or pacing
- oversensing (contact potentials)
✔✔make/break signals are due to - ✔✔inner INSULATOR fracture
✔✔Automatic Mode Switching (AMS) - ✔✔When an atrial rate exceeds a predetermined
value, the device switches from a tracking DDD mode to a nontracking VVI mode
At rates between the upper tracking rate and the mode switch rate, the device will
exhibit pacemaker Wenkebach behavior until it reaches the 2:1 block point, it will then
begin 2:1 behavior
✔✔Main purpose of Fallback - ✔✔to avoid rapid and prolonged ventricular pacing
initiated by the sensing of atrial arrhythmias
fallback is used to prevent a sudden rate drop when the atrial rate exceeds the upper
rate limit of the device, it slowly and progressively slowing the ventricular paced rate.
it disassociates the ventricular output from the sinus rate until the sinus rate drops to the
upper ate limit of the fallback rate
✔✔Rate smoothing - ✔✔the pulse generator stores in its memory the most recent RR
interval and does not allow the next RR interval to be less than the preceding RR
interval minus the programmed percentage nor does it allow it to be greater than the
preceding RR interval plus the programmed percentage
✔✔how to calculate the rate smoothing atrial and ventricular window - ✔✔atrial window
= (previous RR interval +/- rate smoothing value) - AV delay
ventricular window = (previous RR interval +/- rate smoothing value)
✔✔downside of rate smoothing function - ✔✔may lead to VA conduction and PMT
because a PAC will lead to delay AV conduction
✔✔Chagas disease - ✔✔the vector is in insect
parasite Trypanosoma cruizi
an acute infection of the heart is the main result, damaging the heart muscle
heart muscle fibers are slowly replaced by scar tissue, thinning the walls of the heart,
severely affecting heart function, and ultimately resulting in death
