A Guide to CIED Magnet Responses: Critical Information for Anaesthetists

Abstract

The perioperative management of patients with cardiac implantable electronic devices (CIEDs) has significantly improved in recent years. However, the use of magnets remains insufficiently defined in guidelines, despite ongoing variability in magnet responses across different manufacturers and the increasing implantation of leadless devices, whose response to magnet remains unknown. Anaesthetists must be familiar with device-specific magnet responses to ensure optimal perioperative management of CIEDs. Magnets activate a sensor that triggers asynchronous pacing in pacemakers and disables tachyarrhythmia detection in implantable cardioverter-defibrillators. Although magnets often help mitigate the risk of electromagnetic interference, particularly when the surgical site is close to the CIED, their application is not always feasible. In high-risk interference scenarios, especially for supra-umbilical procedures in pacemaker-dependent patients, preoperative electrophysiology consultation is essential for device reprogramming. In emergency situations, a pre-incision magnet test can help identify the specific type of CIED and guide management.

Keywords: Cardiac Implantable Electronic Devices; Electromagnetic interference; Electrophysiology; Magnet; Perioperative Medicine.