Impact of a Radio Frequency Electronic Article Surveillance (EAS) System on Active Implants

In view of the omnipresence of electronic article surveillance (EAS) systems in daily life and the increasing number of patients with active implants, there is concern about adverse electromagnetic interference in particular cardiac pacemakers (CPM) and cardioverter defibrillators (ICD), which due to sensing electrocardial signals are particularly vulnerable. To provide quantitative information interference of monopolar CPM and ICD by EAS systems operating at 8.2MHz radiofrequency electromagnetic fields (EMF) investigations have been performed by exposing numerical anatomical models of pacemaker patients with implants at the conventional left or right pectoral sites and at the abdomen to magnetic fields of a simulated EAS gate source. Investigation of normal position in the centre and worst case with the back next to the gate showed that adverse interference such as inadequate sensing need not be expected at any position. This applies for conventional sensing thresholds even if the exposure span of existing EAS systems is taken into account. However, if full use is made of the newly expanded exposure budget, adverse interference cannot be excluded.

Risk of Pacemaker Patients by TASER X26 Contact Mode Application

The prevalence of pacemaker patients among the general population and of conducted energy devices (CED) for law enforcement and self-defence is increasing. Consequently, the question whether cardiac pacemaker (CPM) patients are on particular risk becomes increasingly important. The risk of Taser X26 electric interference with implanted CPM has been investigated by numerical simulation at MRI-based anatomical models of CPM patients with devices implanted at conventional sites (left pectoral, right pectoral and abdominal) and with the monopolar CPM electrode placed at the ventricular apex. In spite of 10fold higher peak voltages the different coupling conditions make Taser-induced CPM interference voltages lower than those caused by external cardiac defibrillators. It is shown that electric interference considerably depends on ECD electrode orientation. The most unfavourable conditions are encountered with ECD electrodes aligned with the line from the CPM electrode tip to CPM can (EPC line). It could be shown that worst case interference voltages of monopolar pacemakers of any kind of implantation remain below the pulse immunity level as defined in safety standards of implantable cardiac pacemakers and of cardioverter defibrillators. However, interference voltages exceed CPM sensing thresholds. Therefore, capturing should be expected at Taser X26 contact mode application at any position at the upper part of the body including the abdomen, both at frontal and dorsal positions.

Impact of EAS Systems on Implanted Cardiac Pacemakers and Defibrillators

To investigate electromagnetic interference (EMI) of electromagnetic fields (EMF) from electronic article surveillance (EAS) systems with electronic implants numerical anatomical models of pacemaker patients were generated accounting for different implantation sites (left pectoral, right pectoral and abdominal) and body size. Induced interference voltages were calculated with a software package applying the Finite Integration Technique and analysed in dependence on frequency. Results were referred to reported maximum magnetic fields levels measured at EAS systems in the ELF, IF and RF range. With reference to electromagnetic immunity requirements of safety standards of implanted cardiac pacemakers and defibrillators, the numerical analysis showed that the relevance of interference depends on the applied EMF frequency. At EAS systems operating in the RF range, EMI and consequential inadequate pacing is rare but cannot be ruled out. The probability of such events increases at EAS systems in the IF range and even more in the ELF range. Since interference is encountered already at yet existing systems, the situation would be worse if future systems would further increase their emissions by making use of the elevated reference levels recommended in updated exposure guidelines.