EKG certification Certification Pacemakers & Cardiac Devices 2 — Questions and Answers
Question 1: What is 'failure to sense' (undersensing) in a pacemaker?
- The pacemaker detects signals that are not true cardiac events
- The pacemaker fails to recognize the patient's intrinsic heartbeats (Correct answer)
- The pacemaker fires at a rate faster than programmed
- The pacemaker lead becomes dislodged
Correct answer: The pacemaker fails to recognize the patient's intrinsic heartbeats
Undersensing (failure to sense) occurs when the pacemaker does not detect native cardiac depolarizations and fires inappropriately, potentially on top of native beats.
Question 2: What is 'oversensing' in a pacemaker?
- The pacemaker paces at a rate above the upper rate limit
- The pacemaker inappropriately detects non-cardiac signals and inhibits pacing (Correct answer)
- The pacemaker captures the myocardium with excessive current
- The pacemaker tracks atrial activity too rapidly
Correct answer: The pacemaker inappropriately detects non-cardiac signals and inhibits pacing
Oversensing occurs when the pacemaker misinterprets non-cardiac signals (such as muscle artifact or T waves) as intrinsic cardiac activity and inappropriately inhibits pacing output.
Question 3: What is pacemaker syndrome?
- Infection around the pacemaker pocket site
- Symptoms caused by loss of AV synchrony during ventricular-only pacing (Correct answer)
- Pacemaker-induced ventricular fibrillation
- Oversensing causing inappropriate inhibition
Correct answer: Symptoms caused by loss of AV synchrony during ventricular-only pacing
Pacemaker syndrome occurs when VVI pacing causes loss of AV synchrony, leading to symptoms like hypotension, dizziness, fatigue, and pulsations in the neck due to atrial contraction against closed AV valves.
Question 4: In a dual-chamber (DDD) pacemaker, what does the letter 'D' in the THIRD position indicate?
- Dual chambers are paced
- Dual chambers are sensed
- Both inhibition and triggering responses can occur (Correct answer)
- The device has defibrillation capability
Correct answer: Both inhibition and triggering responses can occur
In the NBG code, 'D' in the third position (response to sensing) means the pacemaker has a dual response: it can be inhibited by sensed events in one chamber and triggered in another.
Question 5: What does a rate-responsive (VVIR or DDDR) pacemaker feature do?
- It automatically switches between VVI and DDD modes
- It increases the pacing rate in response to physical activity or metabolic demand (Correct answer)
- It paces the heart faster during sleep
- It adjusts sensitivity based on the lead impedance
Correct answer: It increases the pacing rate in response to physical activity or metabolic demand
The rate-responsive feature (indicated by 'R' in the fourth position of the pacemaker code) uses sensors to detect physical activity or physiological changes and increases the pacing rate to match the patient's metabolic needs.
Question 6: What is the primary purpose of an Implantable Cardioverter-Defibrillator (ICD)?
- To maintain a minimum heart rate via backup pacing only
- To detect and terminate life-threatening ventricular arrhythmias with a shock (Correct answer)
- To continuously monitor and record heart rhythms for later analysis
- To control rapid atrial fibrillation with overdrive pacing
Correct answer: To detect and terminate life-threatening ventricular arrhythmias with a shock
An ICD continuously monitors cardiac rhythm and delivers an internal defibrillation shock to terminate ventricular fibrillation or ventricular tachycardia, preventing sudden cardiac death.
Question 7: On an EKG, what does the absence of pacemaker spikes in a patient with a permanent pacemaker and very slow heart rate most likely indicate?
- Normal pacemaker function with intact intrinsic conduction
- Battery depletion or component failure of the pacemaker (Correct answer)
- Pacemaker-mediated tachycardia
- Electrode lead dislodgment causing oversensing
Correct answer: Battery depletion or component failure of the pacemaker
Absence of pacemaker spikes in a dependent patient with bradycardia strongly suggests pacemaker failure due to battery depletion, component malfunction, or complete lead fracture.
EKG certification Certification Pacemakers & Cardiac Devices 2
What is 'failure to sense' (undersensing) in a pacemaker?