Loss of capture in a pacemaker/ICD patient indicates that the pacing stimulus fails to generate a heartbeat. What is the first step?

• A. Loss of capture indicates pacing stimulus fails to generate a heartbeat; check lead integrity and reposition or replace the lead if necessary.
• B. The device is sensing intrinsic activity and no action is needed.
• C. Battery depletion is the sole cause of loss of capture.
• D. Lead insulation damage always presents with audible alarms.

Answer: (A)

Loss of capture means the pacing stimulus is delivered but the heart does not respond with a beat. The first step is to evaluate the hardware by checking lead integrity and connections. This involves inspecting the lead at the generator header, confirming proper connection, and assessing lead impedance to look for fracture, insulation break, or loose connections. If a lead issue is suspected, repositioning the lead or replacing it is the appropriate next move. Once the lead integrity is established, recheck the pacing thresholds and adjust output if needed.

Sensing intrinsic activity or assuming no action is needed isn’t correct, because loss of capture specifically points to a failure of the stimulus to depolarize the heart, which is most often due to a lead-related problem rather than sensing alone. Battery depletion can cause pacing failure too, but it’s not the sole or most immediate explanation for isolated loss of capture and would be identified on device interrogation. Lead insulation damage doesn’t reliably present with alarms in every case, so it isn’t a guaranteed first clue.