Question

Undersensing occurs as a pacemaker malfunctions when which of the following occurs?

1) The pacing spike occurs at the preset level despite the patient's intrinsic rhythm.
2) The complex does not follow the pacing spike.
3) There is total absence of the pacing spike.
4) There is loss of pacing artifact.

Answer 1

Undersensing occurs as a pacemaker malfunctions when there is total absence of the pacing spike.

Step-by-step explanation:

Undersensing occurs as a pacemaker malfunctions when there is total absence of the pacing spike. In a properly functioning pacemaker, the pacing spike should occur at the preset level despite the patient's intrinsic rhythm. Therefore, option 3) is the correct answer choice. When there is no pacing spike, the pacemaker fails to deliver electrical impulses to the heart, resulting in a lack of coordination and contraction of the heart muscles.