Which condition can lead to failure to capture tissue during pacing?

Which condition can lead to failure to capture tissue during pacing?

• A. Insufficient pacing stimulus or paced during refractory
• B. Lead displacement
• C. Battery depletion
• D. Oversensing

Answer: (A)

Capture depends on delivering a stimulus that is strong enough to depolarize the heart and delivered at a moment when the tissue can respond. If the pacing stimulus is not sufficient in amplitude or duration, it may not reach the threshold to trigger depolarization, so there’s no capture. If the stimulus arrives while the myocardium is in its refractory period, the cells won’t respond, and again there’s no capture. These direct energy and timing issues are the primary reasons a pacemaker might fail to capture tissue during pacing.

Capture depends on delivering a stimulus that is strong enough to depolarize the heart and delivered at a moment when the tissue can respond. If the pacing stimulus is not sufficient in amplitude or duration, it may not reach the threshold to trigger depolarization, so there’s no capture. If the stimulus arrives while the myocardium is in its refractory period, the cells won’t respond, and again there’s no capture. These direct energy and timing issues are the primary reasons a pacemaker might fail to capture tissue during pacing.