ABSTRACT
Public concern for the compatibility of electromagnetic (EM) sources with active implantable medical devices (AIMD) has prompted the development of new systems that can perform accurate exposure studies. EM field interference with active cardiac implants (e.g. implantable cardioverter-defibrillators (ICDs)) can be critical. This paper describes a magnetic field (MF) exposure system and the method developed for testing the immunity of ICD to continuous-wave MFs. The MFs were created by Helmholtz coils, housed in a Faraday cage. The coils were able to produce highly uniform MFs up to 4000 µT at 50 Hz and 3900 µT at 60 Hz, within the test space. Four ICDs were tested. No dysfunctions were found in the generated MFs. These results confirm that the tested ICDs were immune to low frequency MFs.
Subject(s)
Defibrillators, Implantable , Magnetic Fields , Materials Testing/methods , Environment , Equipment Design , Materials Testing/instrumentationABSTRACT
PURPOSE: The operation of implantable cardioverter defibrillators (ICD) can be disrupted by exposure to electromagnetic fields (EMF). In the workplace, some workers can be exposed to EMF higher than in daily life. We present an approach aimed at assessing fitness for work in this type of situation, based on in situ case studies in the absence of clinical and in vivo studies. METHODS: A risk assessment protocol was developed to measure the 50-Hz electric and magnetic fields in the various places where the worker is likely to be present. These measures are taken in the worker's presence, while monitoring the ICD operation. RESULTS: All cases of implanted ICD workers in EDF, the French electricity company (around 130,000 employees), and potentially exposed to high electric and/or magnetic fields, between 2004 and 2009 are presented. These three cases involved different work circumstances, with exposure to 50-Hz electric and/or magnetic fields. No interference of the ICD was observed. CONCLUSIONS: This information provides the basis for the occupational physician to make a decision about fitness for work. This procedure can be extended to other medical implants and to electromagnetic fields frequencies other than 50-Hz.
Subject(s)
Defibrillators, Implantable , Electromagnetic Fields/adverse effects , Occupational Exposure , Adult , Anecdotes as Topic , France , Humans , Middle Aged , Risk Assessment , WorkplaceABSTRACT
The characterisation of population exposure to a 50-Hz magnetic field (MF) is important for assessing health effects of electromagnetic fields. With the aim of estimating and characterising the exposure of the French population to 50-Hz MFs, two representative samples of the population were made. A random selection method based on the distribution of households in different regions of France was used. The samples were carried out starting from a random polling of telephone numbers of households (listed, unlisted fixed phones and cell phones only). A total of 95,362 telephone numbers were dialed to have 2148 volunteers (1060 children and 1088 adults). They all agreed to carrying an EMDEX II meter, measuring and recording MFs, and to filling out a timetable for a 24-hour period. In this article, the methodology of the sample selection and the collection of all necessary information for the realisation of this study are presented.
Subject(s)
Electromagnetic Fields/adverse effects , Environmental Exposure/analysis , Population Surveillance , Adolescent , Adult , Child , Child, Preschool , Female , France , Humans , Infant , Infant, Newborn , Male , Middle Aged , Telephone , Young AdultABSTRACT
UNLABELLED: The effect of 50 Hz and 60 Hz (frequencies of current distribution) and 20 kHz to 50 kHz (frequencies of induction cooktop) magnetic interference on implanted pacemakers have been assessed with the present generation of device technology. Sixty patients implanted in 1998 and 1999 with dual chamber pacemakers from 9 different manufacturers were monitored with telemetry while passing through, and standing between a system of two coils. They generated a 50 Hz or a 60 Hz magnetic field at 50 microT. Then, patients used a cooktop at different power. The recordings were made with the standard setting of "medically correct" sensing parameters chosen for the patients. Then pacemakers were reprogrammed to the unipolar mode, with the highest atrial (A) and ventricular (V) sensitivity that did not induce muscular inhibition while moving. Between each exposure (50 Hz, 60 Hz or 20 kHz to 50 kHz), the pacemaker programmation was controlled. At the end of the tests, pacemakers will be reprogrammed with the standard setting. The medical observer being blind to the existence or not of the magnetic field. No pacemaker was influenced by the vicinity of the magnetic field at medically correct settings. At unipolar high sensitivity, no inhibition nor reprogramming was observed. Transient reversion to interference mode was observed in 6 cases, 3 transient acceleration due to atrial detection of the interference, and one T wave detection by the ventricular lead. All were observed with the 60 Hz, and only 3 with the 50 Hz magnetic field. One device (Biotronik) shifted out of its special program (hysteresis research) during the tests with the induction cooktop, but it maintained its standard program, and the event could not be repeated despite further testing. CONCLUSION: Actual pacemakers do not present any electromagnetic interference with 50 Hz and 60 Hz or induction cooktop frequency working. They are insensitive with medically correct settings. Unusual high sensitivity leads only to noise reversion mode, or transient ventricular tracking.
