Appropriate Delivery of Antitachyarrhythmia Therapy Despite Magnet Placement Over Implanted Cardioverter-Defibrillator: A Case Report.

The fundamental perioperative concern for patients with implantable cardioverter-defibrillators (ICDs) is the potential for electromagnetic interference (EMI) from monopolar electrosurgery. The ICD may interpret electromagnetic signals as a tachyarrhythmia and deliver an inappropriate shock to the patient. Magnet placement is often used to avoid this problem since a magnet will often deactivate an ICD's tachyarrhythmia therapy. We report a case in which magnet placement over an ICD failed to suspend tachyarrhythmia therapy because of imprecise magnet positioning. This case demonstrates the possibility for error when relying on a magnet to suspend tachyarrhythmia therapies.