Inadvertent triggering of supraventricular tachycardia during pacemaker interrogation: Time to lose the magnet?

Abstract

A 22-year-old male had a dual chamber permanent pacemaker (PPM) implanted for complete heart block following aortic valve replacement for Shone’s syndrome 3 months previously. He presented with acute shortness of breath due to severe para-valvular leak with aortic valve dehiscence following a motor vehicle accident. He was scheduled for redo sternotomy and a pre-operative PPM check was undertaken. A programmer wand (Model 2067, Medtronic Inc., Minneapolis, MN, USA) was applied to the patient's PPM site to perform interrogation. During initialization, asynchronous DOO pacing at the magnet rate of 85 bpm was initiated with evidence of both atrial and ventricular capture. Competition from intrinsic rhythm resulted in functional loss of capture. Competitive pacing initiated a narrow complex supraventricular tachycardia at 180 bpm. The tachycardia persisted to result in clinical deterioration until reversion with urgent intravenous metoprolol. Programmer wands from Medtronic (Model 2067 & Encore) and Biotronik (Renamic, Biotronik Inc., Berlin, Germany) have in-built magnets that can cause asynchronous pacing during initialization of interrogation. Removing the magnet in future iterations of PPM programmer wands will mitigate inadvertent arrhythmia induction.<Learning objective: Some pacemaker programmer wands contain in-built magnets that can initiate asynchronous pacing when placed over a cardiac implantable electronic device. This could result in asynchronous pacing and inadvertent triggering of arrhythmia. This risk can be minimized by placing the wand after the programmer is booted up to reduce the duration of asynchronous pacing. Device manufacturers should consider redesigning their products to make magnets redundant in future models of programming wands.>