Which method could potentially lead to arrhythmia detection being suspended in an ICD?

Using a magnet on an implantable cardioverter-defibrillator (ICD) can indeed suspend arrhythmia detection. This is because the application of a magnet is commonly employed in clinical settings as part of the standard protocol to either troubleshoot or intentionally disable certain devices functions, including rhythm detection and shock delivery, particularly during programming or when a temporary deactivation is needed to prevent unnecessary shocks.

The way this works is that the presence of the magnet alters the device's sensing mechanism, which can prevent it from detecting arrhythmias or delivering shocks. This can be useful in various situations, such as when performing tests or procedures that may generate noise or confusion in the device's sensing capabilities.

In contrast, external defibrillation is an emergency procedure meant to restore a normal heart rhythm. Increasing detection rates would generally improve the ICD's ability to identify arrhythmias rather than suspend it. Administering medications may affect cardiac rhythm and overall management of arrhythmias, but it does not directly lead to the suspension of arrhythmia detection in an ICD. Thus, the use of a magnet is the method that specifically results in this effect.