Which of the following is a sign that a Holter monitor may not be functioning properly?

A Holter monitor is a portable device used to continuously monitor the electrical activity of the heart, typically over a period of 24 to 48 hours. Its effective function relies on the proper attachment of electrodes, as this is crucial for accurate data collection and analysis.

When leads become detached, it indicates a malfunction, as the monitor is unable to record the heart's electrical activity at that point. This leads to gaps in data, which can result in incomplete or misleading results regarding the patient's cardiac health, potentially missing critical arrhythmias or other heart-related issues.

The other options do not indicate a malfunctioning Holter monitor. If it is securely in place, this suggests good adherence to the skin, allowing for effective monitoring. Similarly, if a patient reports no discomfort, it typically indicates that the monitor is functioning as intended and is not causing irritation or problems with adhesion. Finally, while a low battery does affect functionality, it is more indicative of a need for maintenance rather than a sign of immediate malfunction, as many monitors have alerts for low battery levels and can be replaced before data collection is compromised.