IBHRE CDRMS Exam Study Set — 2026/2027
IBHRE CARDIAC DEVICE REMOTE MONITORING SPECIALIST (CDRMS) EXAM STUDY SET
2026/2027 | 150 Questions | Exam Prep
International Board of Heart Rhythm Examiners
Instructions: Select the best answer for each question. SATA items require selecting all correct responses.
Ordered items require placing steps in correct sequence. Answers and rationales follow each question.
SECTION I: FOUNDATIONS OF CARDIAC RHYTHM DEVICES (Q1–25)
1. A remote monitoring nurse is reviewing a patient's device interrogation report and notes
the pacing mode is DDD. According to the NASPE/BPEG Generic (NBG) pacemaker code,
what does the third letter 'D' indicate?
A. Dual-chamber sensing
B. Dual-chamber response (inhibited and triggered)
C. Dual-chamber pacing
D. Rate modulation
Correct Answer: B. Dual-chamber response (inhibited and triggered)
Rationale: The NBG code has three positions for antibradycardia pacing: the first position indicates the
chamber(s) paced (D = dual: atrium and ventricle), the second position indicates the chamber(s) where
sensing occurs (D = dual), and the third position indicates the response to a sensed event (D = dual: both
inhibition and triggering). DDD means the device paces and senses both chambers, and responds with both
inhibition and triggering. Rate modulation is indicated by the fourth position letter 'R'. Understanding the
NBG code is fundamental for interpreting device programming reports in remote monitoring.
2. A patient with a single-chamber ventricular pacemaker set to VVI mode is remotely
monitored. The nurse notes the device is functioning in asynchronous pacing at 70 ppm.
What is the MOST likely cause?
A. Lead impedance is elevated
B. Magnet rate has been activated
C. The atrial lead has failed
D. Electromagnetic interference (EMI) is causing oversensing
Correct Answer: B. Magnet rate has been activated
Rationale: Placing a magnet over a pacemaker typically causes it to switch to an asynchronous pacing
mode (AOO, VOO, or DOO depending on the programmed magnet response), pacing at a fixed rate
regardless of the patient's intrinsic rhythm. This is called the magnet rate. For most Medtronic devices, the
magnet rate is 85 ppm (or 100 ppm if ERI), and for Boston Scientific devices it is typically 98 ppm. The
nurse should verify if a magnet was recently applied (e.g., during an MRI or medical procedure). Lead
impedance elevation (A) does not cause asynchronous pacing. Atrial lead failure (C) is irrelevant for a VVI
device. EMI causing oversensing (D) would typically cause inhibition, not asynchronous pacing.
3. During a routine remote transmission review, the nurse identifies that a patient's
implantable cardioverter-defibrillator (ICD) has detected an episode in the VF zone with a
delivered 31-Joule shock. Which of the following BEST describes the typical ICD detection
zone hierarchy from lowest to highest rate?
A. VF zone, fast VT zone, VT zone, monitor zone
B. Monitor zone, VT zone, fast VT zone, VF zone
C. VT zone, VF zone, fast VT zone, monitor zone
D. Monitor zone, fast VT zone, VF zone, VT zone
Correct Answer: B. Monitor zone, VT zone, fast VT zone, VF zone
Rationale: ICD detection zones are organized by heart rate thresholds from lowest to highest: monitor
zone (lowest rate, detection without therapy), VT zone (typically 170-200 bpm, may receive ATP or shock),
1
, IBHRE CDRMS Exam Study Set — 2026/2027
fast VT zone (typically 200-250 bpm, may receive ATP or shock), and VF zone (highest rate, typically >250
bpm, shock therapy). The monitor zone allows the device to record arrhythmia episodes without delivering
therapy. Understanding detection zone hierarchy is essential for remote monitoring nurses when triaging
arrhythmia alerts and determining clinical urgency.
4. A patient with a cardiac resynchronization therapy (CRT) device is remotely monitored.
The transmission shows a biventricular pacing percentage of 72%. What is the MINIMUM
biventricular pacing percentage recommended for optimal clinical benefit in CRT patients?
A. 50%
B. 70%
C. 90%
D. 100%
Correct Answer: C. 90%
Rationale: Current guidelines recommend a minimum biventricular pacing percentage of greater than
90% for optimal clinical benefit in CRT patients. Studies have demonstrated that patients with less than
90% biventricular pacing have significantly worse outcomes, including higher rates of heart failure
hospitalization and mortality. A biventricular pacing percentage of 72% is suboptimal and should prompt
the remote monitoring nurse to investigate potential causes such as frequent premature ventricular
contractions (PVCs), atrial arrhythmias, or inappropriate atrial sensing, and escalate to the physician for
potential programming adjustments.
5. A remote monitoring coordinator is reviewing device data and notes that a patient's
pacemaker battery voltage has reached the Elective Replacement Indicator (ERI). What does
this indicate?
A. The battery is depleted and the device is no longer functioning
B. The device has reached a voltage threshold indicating that generator replacement should be scheduled
C. The battery is in the normal operating range and no action is needed
D. The device has switched to a backup mode with reduced functionality
Correct Answer: B. The device has reached a voltage threshold indicating that generator
replacement should be scheduled
Rationale: The Elective Replacement Indicator (ERI) is a manufacturer-defined battery voltage threshold
that signals the physician to schedule elective generator replacement. At ERI, the device typically switches
to a simpler pacing mode to conserve battery life (e.g., VVI instead of DDD) and may disable certain
diagnostic features. The device continues to function at ERI but with limited operational life remaining
(typically 3-6 months). End of Life (EOL) occurs when the battery can no longer support pacing. End of
Service (EOS) is the final point where all device function ceases. The Replacement Recommended Time
(RRT) is an earlier advisory threshold used by some manufacturers (e.g., Medtronic).
6. Select all that apply. A remote monitoring nurse is educating a new patient about their
transvenous cardiac device leads. Which of the following are standard lead connector types
used in implantable cardiac devices? [Select All That Apply]
A. DF-1
B. IS-1
C. IS-4
D. DF-4
E. USB-C
Correct Answer: A. DF-1, B. IS-1, C. IS-4, D. DF-4
Rationale: DF-1 (A) is a single-pass connector (one pin per lead) used for traditional pacing and ICD
leads. IS-1 (B) is the International Standard for low-voltage pacing/sensing leads. IS-4 (C) is a four-pin
connector used with quadripolar LV leads for CRT devices, allowing multiple pacing vectors. DF-4 (D) is a
four-pin connector used with high-voltage ICD leads that integrates the shock, sensing, and pacing
2
, IBHRE CDRMS Exam Study Set — 2026/2027
connections into a single connector, reducing the number of set-screws. USB-C (E) is a universal serial bus
connector for consumer electronics and has no application in cardiac device systems.
7. A patient with a leadless pacemaker is enrolled in a remote monitoring program. Which of
the following statements about leadless pacemakers is CORRECT?
A. Leadless pacemakers require a transvenous lead inserted through the subclavian vein
B. Leadless pacemakers are implanted in the right ventricular apex via a femoral vein catheter delivery
system
C. Leadless pacemakers are contraindicated in patients with atrial fibrillation
D. Leadless pacemakers cannot be remotely monitored
Correct Answer: B. Leadless pacemakers are implanted in the right ventricular apex via a
femoral vein catheter delivery system
Rationale: Leadless pacemakers (e.g., Medtronic Micra, Abbott Nanostim) are self-contained devices
implanted directly into the right ventricle via a femoral vein catheter delivery system. They eliminate the
need for transvenous leads and a subcutaneous pocket, reducing lead-related complications such as
infection, fracture, and venous obstruction. They can provide VVI(R) pacing and are remotely monitorable.
They may be used in patients with atrial fibrillation (C) but do not provide atrial pacing. They are
compatible with remote monitoring systems (D), providing data on pacing thresholds, impedance, heart
rate, and activity.
8. A remote monitoring nurse is reviewing an ICD transmission showing that Anti-
Tachycardia Pacing (ATP) was delivered for a ventricular tachycardia episode. What is the
PRIMARY purpose of ATP therapy?
A. To immediately cardiovert the patient using a high-energy shock
B. To painlessly terminate ventricular tachycardia by delivering pacing stimuli that interrupt the
reentrant circuit
C. To prevent atrial fibrillation from conducting to the ventricles
D. To increase the heart rate during bradycardia episodes
Correct Answer: B. To painlessly terminate ventricular tachycardia by delivering pacing
stimuli that interrupt the reentrant circuit
Rationale: Anti-Tachycardia Pacing (ATP) is a painless therapy that delivers rapid pacing stimuli (burst,
ramp, or ramp+ patterns) to interrupt the reentrant circuit of monomorphic ventricular tachycardia,
thereby terminating the arrhythmia without the need for a painful shock. ATP is typically attempted first
for VT in the monitored or VT zone before escalating to defibrillation shocks. Studies have shown that ATP
successfully terminates approximately 70-80% of monomorphic VT episodes. Cardioversion uses a shock,
not pacing (A). ATP does not prevent AF conduction (C) or treat bradycardia (D).
9. A patient with a subcutaneous implantable cardioverter-defibrillator (S-ICD) is remotely
monitored. Which of the following is a key difference between a transvenous ICD and an S-
ICD?
A. The S-ICD does not provide antitachycardia pacing (ATP)
B. The S-ICD provides biventricular pacing
C. The S-ICD requires a transvenous lead in the right ventricle
D. The S-ICD cannot deliver defibrillation shocks
Correct Answer: A. The S-ICD does not provide antitachycardia pacing (ATP)
Rationale: The subcutaneous ICD (S-ICD) differs from transvenous ICDs in that it does not have
intracardiac leads and therefore cannot provide antitachycardia pacing (ATP), bradycardia pacing, or
CRT. The S-ICD consists of a pulse generator implanted in the left lateral chest wall and a subcutaneous
lead tunneled along the sternum. It senses the subcutaneous ECG and delivers defibrillation shocks (up to
80J) for life-threatening ventricular arrhythmias. It is ideal for patients who do not require pacing and are
at risk for lead-related complications. Newer models (e.g., EMBLEM S-ICD with Smart Pass technology)
have improved sensing algorithms.
3
, IBHRE CDRMS Exam Study Set — 2026/2027
10. During remote data review, a nurse notes that a patient's atrial lead sensing amplitude has
decreased from 3.5 mV to 1.2 mV over the past 6 months. What is the typical minimum
acceptable atrial sensing amplitude for reliable device function?
A. 0.2 mV
B. 0.5 mV
C. 1.5 mV
D. 5.0 mV
Correct Answer: C. 1.5 mV
Rationale: The typical minimum acceptable atrial sensing amplitude for reliable device function is 1.5
mV, with many clinicians preferring values greater than 2.0 mV. A decrease from 3.5 mV to 1.2 mV is
concerning and approaches the undersensing threshold, which could lead to inappropriate pacing or loss of
atrial tracking. This trend warrants investigation for potential causes including lead maturation, fibrosis
at the electrode-tissue interface, lead dislodgement, or lead fracture. The nurse should escalate this finding
to the electrophysiologist for further evaluation, which may include an in-office device interrogation and
imaging studies.
11. A remote monitoring nurse reviews a transmission from a 72-year-old patient with a
Medtronic Advisa DR MRI pacemaker implanted 4 years ago. The data shows: atrial lead
impedance 450 ohms (previously 500 ohms), ventricular lead impedance 650 ohms
(previously 680 ohms), battery voltage 2.73V (ERI at 2.62V), and biventricular pacing not
applicable (it is a dual-chamber pacemaker, not CRT). The patient has been asymptomatic.
Which finding should the nurse prioritize for physician notification?
A. The minor decrease in atrial lead impedance from 500 to 450 ohms
B. The battery voltage approaching the ERI threshold at 2.73V
C. The minor decrease in ventricular lead impedance from 680 to 650 ohms
D. The fact that the patient is asymptomatic
Correct Answer: B. The battery voltage approaching the ERI threshold at 2.73V
Rationale: The battery voltage of 2.73V approaching the ERI threshold (2.62V for Medtronic Advisa) is
the most clinically significant finding. Although the patient is asymptomatic, the device is nearing end-of-
service voltage, and generator replacement surgery should be planned electively. The minor impedance
changes (A and C) are within normal physiological variation and do not indicate lead fracture (which
typically presents with sudden impedance rise >1000 ohms or drop <200 ohms). Asymptomatic status (D)
does not eliminate the need to act on the approaching ERI, as the device could reach ERI before the next
scheduled follow-up.
12. A remote monitoring nurse is reviewing a device report that shows a ventricular capture
threshold of 2.5 V at 0.4 ms pulse width. Which statement BEST describes capture threshold?
A. The minimum voltage required for the device to sense intrinsic cardiac electrical activity
B. The minimum electrical stimulus required to consistently depolarize the myocardium and produce a
paced beat
C. The maximum voltage the device can deliver before causing tissue damage
D. The impedance measured between the lead electrode and the pacemaker can
Correct Answer: B. The minimum electrical stimulus required to consistently depolarize the
myocardium and produce a paced beat
Rationale: Capture threshold is defined as the minimum electrical output (voltage at a given pulse width)
required to consistently depolarize the myocardium and produce a paced beat. It is measured during
device interrogation by decreasing the output until capture is lost. A chronic capture threshold of 2.5V at
0.4ms is elevated (typical chronic values are 0.5-1.5V for ventricular leads) and may indicate lead issues,
exit block, or metabolic changes. Sensing amplitude (A) is the intracardiac signal detected by the lead.
Maximum output (C) is limited by the device but not the capture threshold. Impedance (D) is a measure of
lead circuit resistance, not capture.
4
IBHRE CARDIAC DEVICE REMOTE MONITORING SPECIALIST (CDRMS) EXAM STUDY SET
2026/2027 | 150 Questions | Exam Prep
International Board of Heart Rhythm Examiners
Instructions: Select the best answer for each question. SATA items require selecting all correct responses.
Ordered items require placing steps in correct sequence. Answers and rationales follow each question.
SECTION I: FOUNDATIONS OF CARDIAC RHYTHM DEVICES (Q1–25)
1. A remote monitoring nurse is reviewing a patient's device interrogation report and notes
the pacing mode is DDD. According to the NASPE/BPEG Generic (NBG) pacemaker code,
what does the third letter 'D' indicate?
A. Dual-chamber sensing
B. Dual-chamber response (inhibited and triggered)
C. Dual-chamber pacing
D. Rate modulation
Correct Answer: B. Dual-chamber response (inhibited and triggered)
Rationale: The NBG code has three positions for antibradycardia pacing: the first position indicates the
chamber(s) paced (D = dual: atrium and ventricle), the second position indicates the chamber(s) where
sensing occurs (D = dual), and the third position indicates the response to a sensed event (D = dual: both
inhibition and triggering). DDD means the device paces and senses both chambers, and responds with both
inhibition and triggering. Rate modulation is indicated by the fourth position letter 'R'. Understanding the
NBG code is fundamental for interpreting device programming reports in remote monitoring.
2. A patient with a single-chamber ventricular pacemaker set to VVI mode is remotely
monitored. The nurse notes the device is functioning in asynchronous pacing at 70 ppm.
What is the MOST likely cause?
A. Lead impedance is elevated
B. Magnet rate has been activated
C. The atrial lead has failed
D. Electromagnetic interference (EMI) is causing oversensing
Correct Answer: B. Magnet rate has been activated
Rationale: Placing a magnet over a pacemaker typically causes it to switch to an asynchronous pacing
mode (AOO, VOO, or DOO depending on the programmed magnet response), pacing at a fixed rate
regardless of the patient's intrinsic rhythm. This is called the magnet rate. For most Medtronic devices, the
magnet rate is 85 ppm (or 100 ppm if ERI), and for Boston Scientific devices it is typically 98 ppm. The
nurse should verify if a magnet was recently applied (e.g., during an MRI or medical procedure). Lead
impedance elevation (A) does not cause asynchronous pacing. Atrial lead failure (C) is irrelevant for a VVI
device. EMI causing oversensing (D) would typically cause inhibition, not asynchronous pacing.
3. During a routine remote transmission review, the nurse identifies that a patient's
implantable cardioverter-defibrillator (ICD) has detected an episode in the VF zone with a
delivered 31-Joule shock. Which of the following BEST describes the typical ICD detection
zone hierarchy from lowest to highest rate?
A. VF zone, fast VT zone, VT zone, monitor zone
B. Monitor zone, VT zone, fast VT zone, VF zone
C. VT zone, VF zone, fast VT zone, monitor zone
D. Monitor zone, fast VT zone, VF zone, VT zone
Correct Answer: B. Monitor zone, VT zone, fast VT zone, VF zone
Rationale: ICD detection zones are organized by heart rate thresholds from lowest to highest: monitor
zone (lowest rate, detection without therapy), VT zone (typically 170-200 bpm, may receive ATP or shock),
1
, IBHRE CDRMS Exam Study Set — 2026/2027
fast VT zone (typically 200-250 bpm, may receive ATP or shock), and VF zone (highest rate, typically >250
bpm, shock therapy). The monitor zone allows the device to record arrhythmia episodes without delivering
therapy. Understanding detection zone hierarchy is essential for remote monitoring nurses when triaging
arrhythmia alerts and determining clinical urgency.
4. A patient with a cardiac resynchronization therapy (CRT) device is remotely monitored.
The transmission shows a biventricular pacing percentage of 72%. What is the MINIMUM
biventricular pacing percentage recommended for optimal clinical benefit in CRT patients?
A. 50%
B. 70%
C. 90%
D. 100%
Correct Answer: C. 90%
Rationale: Current guidelines recommend a minimum biventricular pacing percentage of greater than
90% for optimal clinical benefit in CRT patients. Studies have demonstrated that patients with less than
90% biventricular pacing have significantly worse outcomes, including higher rates of heart failure
hospitalization and mortality. A biventricular pacing percentage of 72% is suboptimal and should prompt
the remote monitoring nurse to investigate potential causes such as frequent premature ventricular
contractions (PVCs), atrial arrhythmias, or inappropriate atrial sensing, and escalate to the physician for
potential programming adjustments.
5. A remote monitoring coordinator is reviewing device data and notes that a patient's
pacemaker battery voltage has reached the Elective Replacement Indicator (ERI). What does
this indicate?
A. The battery is depleted and the device is no longer functioning
B. The device has reached a voltage threshold indicating that generator replacement should be scheduled
C. The battery is in the normal operating range and no action is needed
D. The device has switched to a backup mode with reduced functionality
Correct Answer: B. The device has reached a voltage threshold indicating that generator
replacement should be scheduled
Rationale: The Elective Replacement Indicator (ERI) is a manufacturer-defined battery voltage threshold
that signals the physician to schedule elective generator replacement. At ERI, the device typically switches
to a simpler pacing mode to conserve battery life (e.g., VVI instead of DDD) and may disable certain
diagnostic features. The device continues to function at ERI but with limited operational life remaining
(typically 3-6 months). End of Life (EOL) occurs when the battery can no longer support pacing. End of
Service (EOS) is the final point where all device function ceases. The Replacement Recommended Time
(RRT) is an earlier advisory threshold used by some manufacturers (e.g., Medtronic).
6. Select all that apply. A remote monitoring nurse is educating a new patient about their
transvenous cardiac device leads. Which of the following are standard lead connector types
used in implantable cardiac devices? [Select All That Apply]
A. DF-1
B. IS-1
C. IS-4
D. DF-4
E. USB-C
Correct Answer: A. DF-1, B. IS-1, C. IS-4, D. DF-4
Rationale: DF-1 (A) is a single-pass connector (one pin per lead) used for traditional pacing and ICD
leads. IS-1 (B) is the International Standard for low-voltage pacing/sensing leads. IS-4 (C) is a four-pin
connector used with quadripolar LV leads for CRT devices, allowing multiple pacing vectors. DF-4 (D) is a
four-pin connector used with high-voltage ICD leads that integrates the shock, sensing, and pacing
2
, IBHRE CDRMS Exam Study Set — 2026/2027
connections into a single connector, reducing the number of set-screws. USB-C (E) is a universal serial bus
connector for consumer electronics and has no application in cardiac device systems.
7. A patient with a leadless pacemaker is enrolled in a remote monitoring program. Which of
the following statements about leadless pacemakers is CORRECT?
A. Leadless pacemakers require a transvenous lead inserted through the subclavian vein
B. Leadless pacemakers are implanted in the right ventricular apex via a femoral vein catheter delivery
system
C. Leadless pacemakers are contraindicated in patients with atrial fibrillation
D. Leadless pacemakers cannot be remotely monitored
Correct Answer: B. Leadless pacemakers are implanted in the right ventricular apex via a
femoral vein catheter delivery system
Rationale: Leadless pacemakers (e.g., Medtronic Micra, Abbott Nanostim) are self-contained devices
implanted directly into the right ventricle via a femoral vein catheter delivery system. They eliminate the
need for transvenous leads and a subcutaneous pocket, reducing lead-related complications such as
infection, fracture, and venous obstruction. They can provide VVI(R) pacing and are remotely monitorable.
They may be used in patients with atrial fibrillation (C) but do not provide atrial pacing. They are
compatible with remote monitoring systems (D), providing data on pacing thresholds, impedance, heart
rate, and activity.
8. A remote monitoring nurse is reviewing an ICD transmission showing that Anti-
Tachycardia Pacing (ATP) was delivered for a ventricular tachycardia episode. What is the
PRIMARY purpose of ATP therapy?
A. To immediately cardiovert the patient using a high-energy shock
B. To painlessly terminate ventricular tachycardia by delivering pacing stimuli that interrupt the
reentrant circuit
C. To prevent atrial fibrillation from conducting to the ventricles
D. To increase the heart rate during bradycardia episodes
Correct Answer: B. To painlessly terminate ventricular tachycardia by delivering pacing
stimuli that interrupt the reentrant circuit
Rationale: Anti-Tachycardia Pacing (ATP) is a painless therapy that delivers rapid pacing stimuli (burst,
ramp, or ramp+ patterns) to interrupt the reentrant circuit of monomorphic ventricular tachycardia,
thereby terminating the arrhythmia without the need for a painful shock. ATP is typically attempted first
for VT in the monitored or VT zone before escalating to defibrillation shocks. Studies have shown that ATP
successfully terminates approximately 70-80% of monomorphic VT episodes. Cardioversion uses a shock,
not pacing (A). ATP does not prevent AF conduction (C) or treat bradycardia (D).
9. A patient with a subcutaneous implantable cardioverter-defibrillator (S-ICD) is remotely
monitored. Which of the following is a key difference between a transvenous ICD and an S-
ICD?
A. The S-ICD does not provide antitachycardia pacing (ATP)
B. The S-ICD provides biventricular pacing
C. The S-ICD requires a transvenous lead in the right ventricle
D. The S-ICD cannot deliver defibrillation shocks
Correct Answer: A. The S-ICD does not provide antitachycardia pacing (ATP)
Rationale: The subcutaneous ICD (S-ICD) differs from transvenous ICDs in that it does not have
intracardiac leads and therefore cannot provide antitachycardia pacing (ATP), bradycardia pacing, or
CRT. The S-ICD consists of a pulse generator implanted in the left lateral chest wall and a subcutaneous
lead tunneled along the sternum. It senses the subcutaneous ECG and delivers defibrillation shocks (up to
80J) for life-threatening ventricular arrhythmias. It is ideal for patients who do not require pacing and are
at risk for lead-related complications. Newer models (e.g., EMBLEM S-ICD with Smart Pass technology)
have improved sensing algorithms.
3
, IBHRE CDRMS Exam Study Set — 2026/2027
10. During remote data review, a nurse notes that a patient's atrial lead sensing amplitude has
decreased from 3.5 mV to 1.2 mV over the past 6 months. What is the typical minimum
acceptable atrial sensing amplitude for reliable device function?
A. 0.2 mV
B. 0.5 mV
C. 1.5 mV
D. 5.0 mV
Correct Answer: C. 1.5 mV
Rationale: The typical minimum acceptable atrial sensing amplitude for reliable device function is 1.5
mV, with many clinicians preferring values greater than 2.0 mV. A decrease from 3.5 mV to 1.2 mV is
concerning and approaches the undersensing threshold, which could lead to inappropriate pacing or loss of
atrial tracking. This trend warrants investigation for potential causes including lead maturation, fibrosis
at the electrode-tissue interface, lead dislodgement, or lead fracture. The nurse should escalate this finding
to the electrophysiologist for further evaluation, which may include an in-office device interrogation and
imaging studies.
11. A remote monitoring nurse reviews a transmission from a 72-year-old patient with a
Medtronic Advisa DR MRI pacemaker implanted 4 years ago. The data shows: atrial lead
impedance 450 ohms (previously 500 ohms), ventricular lead impedance 650 ohms
(previously 680 ohms), battery voltage 2.73V (ERI at 2.62V), and biventricular pacing not
applicable (it is a dual-chamber pacemaker, not CRT). The patient has been asymptomatic.
Which finding should the nurse prioritize for physician notification?
A. The minor decrease in atrial lead impedance from 500 to 450 ohms
B. The battery voltage approaching the ERI threshold at 2.73V
C. The minor decrease in ventricular lead impedance from 680 to 650 ohms
D. The fact that the patient is asymptomatic
Correct Answer: B. The battery voltage approaching the ERI threshold at 2.73V
Rationale: The battery voltage of 2.73V approaching the ERI threshold (2.62V for Medtronic Advisa) is
the most clinically significant finding. Although the patient is asymptomatic, the device is nearing end-of-
service voltage, and generator replacement surgery should be planned electively. The minor impedance
changes (A and C) are within normal physiological variation and do not indicate lead fracture (which
typically presents with sudden impedance rise >1000 ohms or drop <200 ohms). Asymptomatic status (D)
does not eliminate the need to act on the approaching ERI, as the device could reach ERI before the next
scheduled follow-up.
12. A remote monitoring nurse is reviewing a device report that shows a ventricular capture
threshold of 2.5 V at 0.4 ms pulse width. Which statement BEST describes capture threshold?
A. The minimum voltage required for the device to sense intrinsic cardiac electrical activity
B. The minimum electrical stimulus required to consistently depolarize the myocardium and produce a
paced beat
C. The maximum voltage the device can deliver before causing tissue damage
D. The impedance measured between the lead electrode and the pacemaker can
Correct Answer: B. The minimum electrical stimulus required to consistently depolarize the
myocardium and produce a paced beat
Rationale: Capture threshold is defined as the minimum electrical output (voltage at a given pulse width)
required to consistently depolarize the myocardium and produce a paced beat. It is measured during
device interrogation by decreasing the output until capture is lost. A chronic capture threshold of 2.5V at
0.4ms is elevated (typical chronic values are 0.5-1.5V for ventricular leads) and may indicate lead issues,
exit block, or metabolic changes. Sensing amplitude (A) is the intracardiac signal detected by the lead.
Maximum output (C) is limited by the device but not the capture threshold. Impedance (D) is a measure of
lead circuit resistance, not capture.
4
