DC Cardiac Pacemaker Therapy & Management 2

Question 1

Which ECG finding is most consistent with pacemaker failure to capture?

Accepted Answer

Pacemaker spikes with no following QRS complex

Answer

Failure to capture is identified on ECG by pacemaker spikes that are not followed by a QRS complex, indicating the stimulus failed to depolarize the myocardium.

Question 2

A demand pacemaker fires during periods of adequate intrinsic heart rate. This finding most likely indicates:

Accepted Answer

Failure to sense (undersensing)

Answer

Undersensing occurs when the pacemaker fails to detect intrinsic cardiac activity, causing it to fire inappropriately and compete with the patient's own rhythm.

Question 3

Oversensing in a permanent pacemaker most commonly results in:

Accepted Answer

Inhibition of pacing, potentially causing symptomatic bradycardia

Answer

Oversensing causes the pacemaker to misinterpret non-cardiac signals (e.g., T-waves, myopotentials) as intrinsic events and inhibit its output, which can lead to pauses or bradycardia.

Question 4

What is the most common cause of pacemaker failure to capture in the early post-implant period?

Accepted Answer

Lead dislodgement

Answer

Lead dislodgement is the most common cause of failure to capture in the early post-implant period, as leads are not yet fully anchored in the myocardium.

Question 5

Pacemaker-mediated tachycardia (PMT) in a dual-chamber pacemaker is caused by:

Accepted Answer

Retrograde atrial activation being sensed and triggering repetitive ventricular pacing

Answer

PMT occurs when ventricular pacing causes retrograde conduction to the atria; the atrial lead senses this signal and triggers another ventricular pace, creating a reentrant loop.

(DC) Dysrhythmia Certification Practice Test

(DC) Dysrhythmia Certification Practice Test

DC Cardiac Pacemaker Therapy & Management 2