Methods and devices are provided for detecting a magnetic field in a presence of an implantable medical device (IMD). The IMD includes at least one electrode and a magnetic detection sensor configured to detect a magnetic field of an external magnetic source. The IMD includes a notification circuit, and an arrhythmia circuit configured to analyze cardiac signals sensed by the electrode and to deliver a therapy based on the cardiac signals. The IMD includes an electronics circuit that is configured to suspend the delivery of the therapy in response to detection of the magnetic field by the magnetic field sensor. The electronics circuit is configured to trigger the notification circuit to generate a notification output in response to the detection of the magnetic field indicating that the therapy has been suspended.