Inappropriate implantable cardioverter-defibrillator magnet-mode switch induced by a laptop computer

An implantable cardioverter-defibrillator (ICD) experienced electromagnetic interference from a laptop computer's hard disk. The patient with the ICD was using his laptop computer at home while lying on his bed. The laptop was positioned on his chest, when he heard a beeping sound from the ICD, indicating magnet mode conversion. This situation was replicated in a controlled environment, and the conversion was found to be due to the static magnetic field produced by the laptop's hard disk. The ICD's conversion to magnet mode can be dangerous because it ends all tachyarrhythmia detections and therapies.