What does the return of a pre-pacemaker rhythm in a patient with a pacemaker indicate?

The return of a pre-pacemaker rhythm in a patient with a pacemaker indicates a failure to pace. This situation arises when the pacemaker fails to deliver electrical impulses to stimulate the heart, allowing the intrinsic rhythm to resume. In a properly functioning pacemaker, when pacing is needed, the device should consistently send out pacing signals to maintain heart rhythm. If the intrinsic rhythm returns, it suggests that the pacemaker is not effectively managing the heart's rhythm as intended.

In evaluating this context, failure to sense refers to the pacemaker not detecting the heart’s native electrical activity, which typically results in inappropriate pacing, but does not align with a return to the original rhythm. Failure to capture involves the pacemaker delivering impulses, but the heart does not respond appropriately to these signals, which would also not result in a complete return to pre-pacemaker rhythm. Incorrect lead placement could lead to multiple issues, including failure to capture or sense, but it is less specific than the direct indication of failure to pace when the pre-pacemaker rhythm re-emerges.