CCDS IBHRE EXAM PREP COMPREHENSIVE
EXAM Q&A 2026 STUDY GUIDE
◉ Main purpose of Fallback
Answer: 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
Answer: 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
Answer: atrial window = (previous RR interval +/- rate smoothing
value) - AV delay
ventricular window = (previous RR interval +/- rate smoothing
value)
,◉ downside of rate smoothing function
Answer: may lead to VA conduction and PMT because a PAC will lead
to delay AV conduction
◉ Chagas disease
Answer: 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
◉ serial connections
Answer: uses a single impedance to determine the output current
◉ parallel connection
Answer: occur when there are two independent impedance
the sum of the output current is used to determine the final lead
impedance
◉ crosstalk
, Answer: an inappropriate detection of a pacemaker-generated event
in one channel by the sensing of the other channel that causes
inhibition of the second channel's output
◉ When does crosstalk occur?
Answer: 1. when the atrial output is at a high value (>5V)
2. the ventricular sensitivity is high (usually <1mV)
3. when the insulation has been rubbed away from two leads in very
closed proximity and the energy is transferred to the ventricular
lead at the time of an atrial output
◉ how to prevent crosstalk
Answer: -a detection window immediately after the atrial output
pulse
- device resets the AVD interval
- at the end of the shortened AVD a ventricular output is issued
- or increase the ventricular blanking period
◉ how to minimize pain for transcutaneous external pacing?
Answer: - increase electrode surface area
- longer pulse duration
- placing electrode over area with least skeletal muscle
EXAM Q&A 2026 STUDY GUIDE
◉ Main purpose of Fallback
Answer: 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
Answer: 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
Answer: atrial window = (previous RR interval +/- rate smoothing
value) - AV delay
ventricular window = (previous RR interval +/- rate smoothing
value)
,◉ downside of rate smoothing function
Answer: may lead to VA conduction and PMT because a PAC will lead
to delay AV conduction
◉ Chagas disease
Answer: 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
◉ serial connections
Answer: uses a single impedance to determine the output current
◉ parallel connection
Answer: occur when there are two independent impedance
the sum of the output current is used to determine the final lead
impedance
◉ crosstalk
, Answer: an inappropriate detection of a pacemaker-generated event
in one channel by the sensing of the other channel that causes
inhibition of the second channel's output
◉ When does crosstalk occur?
Answer: 1. when the atrial output is at a high value (>5V)
2. the ventricular sensitivity is high (usually <1mV)
3. when the insulation has been rubbed away from two leads in very
closed proximity and the energy is transferred to the ventricular
lead at the time of an atrial output
◉ how to prevent crosstalk
Answer: -a detection window immediately after the atrial output
pulse
- device resets the AVD interval
- at the end of the shortened AVD a ventricular output is issued
- or increase the ventricular blanking period
◉ how to minimize pain for transcutaneous external pacing?
Answer: - increase electrode surface area
- longer pulse duration
- placing electrode over area with least skeletal muscle
