What can lead to 'failure to sense' issues in a pacemaker?

The 'failure to sense' issue in a pacemaker primarily occurs when the device is unable to detect the heart's intrinsic electrical activity. This can often be attributed to improper placement of leads. When the leads are not positioned correctly within the heart, they may fail to accurately pick up the electrical signals that the heart generates. This misalignment can result from technical factors during implantation or changes in the heart structure over time, which further complicate proper sensing.

Other potential causes, while relevant to pacemaker functionality, might not directly lead to a 'failure to sense' scenario. For example, battery exhaustion would typically lead to the pacemaker being unable to pace rather than sensing issues specifically. Similarly, while a very low heart rate might influence pacemaker function, it usually does not prevent sensing; instead, it may trigger pacing. Medication interactions could affect the heart rhythm, but they would not inherently alter the pacemaker's ability to sense intrinsic beats when leads are properly placed. Thus, improper lead placement is a critical factor specifically linked to sensing failure.