How Should We Prepare the Patient With a Pacemaker/Implantable Cardioverter-Defibrillator?

An Unexpected Magnet Response of a Biotronik Pacemaker in Automatic Mode: A Case Report

“…The use of electrosurgery within 15 cm of the pulse generator of the pacemaker is a known risk factor for EMI. [1][2][3]9 Standard risk mitigation strategies include positioning the dispersive electrode to divert the electrical return pathway away from the pulse generator and leads, using short bursts of monopolar electrosurgery or using bipolar electrosurgery. 1,2,10 The nerve monitoring often used for thyroid surgery is a form of electromyography where a monopolar probe stimulates the recurrent laryngeal nerve to produce vocal cord motion, which is detected by surface electrodes on a specialized endotracheal tube.…”

“…However, the use of asynchronous pacing for pacingdependent patients in surgeries where electromyography will be used near the pacemaker is recommended. [1][2][3][4] Magnets are commonly used to change a pacemaker to an asynchronous pacing mode. For some pacemakers, the magnet response can be programmed by a CIED expert.…”

“…Lack of awareness of magnet response can lead to incorrect conclusions of pacemaker malfunction. 1,3,6,7,12 Biotronik has 3 modes of magnet response: AUTO, SYNC, and ASYNC. [5][6][7][8][9] The magnet response with the AUTO mode directs a pacemaker to asynchronously pace (ie, DOO) at a rate of 90 bpm for 10 beats, after which the pacemaker reverts to the original pacing mode.…”

“…[5][6][7][8][9] The magnet response with the AUTO mode directs a pacemaker to asynchronously pace (ie, DOO) at a rate of 90 bpm for 10 beats, after which the pacemaker reverts to the original pacing mode. 3,5,8 The AUTO mode can be used to obtain 10-beat electrocardiograms with pacing to assess device function with certain features disabled, such as the event counter, and may be more comfortable for patients while these assessments are made according to Biotronik. 5,6 A Biotronik pacemaker in the SYNC mode will not respond to magnet application with asynchronous pacing, but will continue with the original pacing settings.…”

“…GLOSSARY ASYNC = asynchronous magnet mode; AUTO = automatic magnet mode; bpm = beats per minute; CIED = cardiovascular implantable electronic device; DDD = synchronous dual-chamber pacing; DOO = asynchronous dual-chamber pacing; EMI = electromagnetic interference; ICD = implantable cardioverter-defibrillator; SYNC = synchronous magnet mode P erioperative management of pacing-dependent patients may require asynchronous pacing to prevent oversensing of electromagnetic interference (EMI) by the pacemaker. [1][2][3][4] Magnet application is one way this is accomplished. Pacemaker manufacturers have sophisticated technologies with varied responses to a magnet, which can have important implications intraoperatively.…”