INTERFERENCE FROM A HAND-HELD RADIOFREQUENCY REMOTE-CONTROL CAUSING DISCHARGE OF AN IMPLANTABLE DEFIBRILLATOR

A 46-year-old man with a history of sustained monomorphic ventricular tachycardia underwent an implantation of a third generation multiprogr ammable implantable cardioverter defibrillator. One year post implant, while manipulating a remote control to a radiofrequency modulated toy car, the patient experienced a defibrillator discharge not preceded b y an arrhythmia prodrome. Subsequent interrogation of the defibrillato r revealed that a 34-joule shock had been delivered and had been prece ded by RR intervals ranging from 141-406 msec, consistent with sensing lead noise. The remote control utilizes a 12-volt battery and has a c arrier frequency of 75.95 MHz and a modulating frequency of 50 Hz. Eva luation of the remote control and defibrillator interaction revealed t hat the remote control was able to trigger tachyarrhythmia sensing and reproduce the clinical episode. Interference was present only when th e remote control was within 8 cm of the pulse generator and at specifi c angles relative to the device and only when the antenna length was > 45 cm. Interference was eliminated when a ground wire was attached to the antenna and when an aluminium shield was placed between the pulse generator and the remote control. This case report suggests that pati ents with third generation multiprogrammable defibrillators should be cautioned against close contact with potential sources of electromagne tic interference, such as remote control units.