Final answer:
The condition when a pacemaker cannot capture the heart's electrical signals is called pacemaker loss of capture. This can arise from lead displacement, battery issues, or threshold alterations, and may lead to severe cardiac complications if not addressed.
Step-by-step explanation:
When a pacemaker loses its ability to capture the heart's electrical signals, the condition is called pacemaker loss of capture. This situation may occur due to several factors such as lead displacement, battery failure, or changes in the myocardial threshold. An artificial pacemaker is a device implanted to regulate the heart rate by delivering timed electrical impulses, ensuring that the heart continues to contract and pump blood efficiently. Pacemakers have sensors that detect the body's activity and can adjust the heart rate accordingly. However, when pacemaker loss of capture occurs, it fails to stimulate the heart muscle, potentially leading to serious cardiac complications.