Determining EMC Test Levels for Implantable Devices in Bipolar Lead Configuration

Abstract Certain low-frequency magnetic fields cause interference in implantable medical devices. Electromagnetic compatibility (EMC) standards prescribe injecting voltages into a device under evaluation to simplify testing while approximating or simulating real-world exposure situations to low-frequency magnetic fields. The EMC standard ISO 14117:2012, which covers implantable pacemakers and implantable cardioverter defibrillators (ICDs), specifies test levels for the bipolar configuration of sensing leads as being one-tenth of the levels for the unipolar configuration. The committee authoring this standard questioned this testing level difference and its clinical relevance. To evaluate this issue of EMC test levels, we performed both analytical calculations and computational modeling to determine a basis for this difference. Analytical calculations based upon Faraday's law determined the magnetically induced voltage in a 37.6-cm lead. Induced voltages were studied in a bipolar lead configuration with various spacing between a distal tip electrode and a ring electrode. Voltages induced in this bipolar lead configuration were compared with voltages induced in a unipolar lead configuration. Computational modeling of various lead configurations was performed using electromagnetic field simulation software. The two leads that were insulated, except for the distal and proximal tips, were immersed in a saline-conducting media. The leads were parallel and closely spaced to each other along their length. Both analytical calculations and computational modeling support continued use of a one-tenth amplitude reduction for testing pacemakers and ICDs in bipolar mode. The most recent edition of ISO 14117 includes rationale from this study.

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Interference of low frequency magnetic fields with implantable cardioverter-defibrillators

Scandinavian Cardiovascular Journal ◽

10.3109/14017431.2012.716525 ◽

2012 ◽

Vol 46 (5) ◽

pp. 308-314 ◽

Cited By ~ 8

Author(s):

Maria Tiikkaja ◽

Tommi Alanko ◽

Harri Lindholm ◽

Maila Hietanen ◽

Lauri Toivonen ◽

...

Keyword(s):

Magnetic Fields ◽

Low Frequency ◽

Implantable Cardioverter Defibrillators ◽

Cardioverter Defibrillators

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Implantable cardioverter-defibrillators exposed to low frequency magnetic fields

2011 XXXth URSI General Assembly and Scientific Symposium ◽

10.1109/ursigass.2011.6051387 ◽

2011 ◽

Author(s):

Juliano Katrib ◽

Pierre Schmitt ◽

Isabelle Magne ◽

Djilali Kourtiche ◽

Martine Souques ◽

...

Keyword(s):

Magnetic Fields ◽

Low Frequency ◽

Implantable Cardioverter Defibrillators ◽

Cardioverter Defibrillators

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Magnetic field of complex helical conductors

Archives of Electrical Engineering ◽

10.2478/aee-2013-0043 ◽

2013 ◽

Vol 62 (4) ◽

pp. 533-540 ◽

Cited By ~ 5

Author(s):

Krzysztof Budnik ◽

Wojciech Machczyński

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Electric Power ◽

Electromagnetic Compatibility ◽

Complex Geometry ◽

Phase Distribution ◽

Low Frequency ◽

Software Tool ◽

Helical Structure ◽

Analytical Formulas

Abstract Transmission of the electric power is accompanied with generation of low - frequency electromagnetic fields. Electromagnetic compatibility studies require that the fields from sources of electric power be well known. Unfortunately, many of these sources are not defined to the desired degree of accuracy. This applies e.g. to the case of the twisted-wire pair used in telephone communication; already practiced is twisting of insulated high-voltage three phase power cables and single-phase distribution cables as well. The paper presents a theoretical study of the calculation of magnetic fields in vicinity of conductors having helical structure. For the helical conductor with finite length the method is based on the Biot-Savart law. Since the lay-out of the cables is much more similar to a broken line than to strait line, in the paper the magnetic flux densities produced by helical conductor of complex geometry are also derived. The analytical formulas for calculating the 3D magnetic field can be used by a software tool to model the magnetic fields generated by e.g. twisted wires, helical coils, etc.

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A Positioning System Based on Low-Frequency Magnetic Fields

10.36227/techrxiv.15081480.v1 ◽

2021 ◽

Author(s):

Paolo Carbone ◽

Valter Pasku ◽

Alessio De Angelis ◽

Marco Dionigi ◽

Guido De Angelis ◽

...

Keyword(s):

Magnetic Fields ◽

Low Frequency ◽

Outdoor Environment ◽

Positioning System ◽

Induced Voltage ◽

Quality Factors ◽

Large Area ◽

Key Factor ◽

Loop Antennas ◽

Transmitting Antenna

This paper describes the design and the realization of a low-frequency ac magnetic-field-based indoor positioning system (PS). The system operation is based on the principle of inductive coupling between wire loop antennas. Specifically, due to the characteristics of the ac artificially generated magnetic fields, the relation between the induced voltage and the distance is modeled with a linear behavior in a bilogarithmic scale when a configuration with coplanar, thus equally oriented, antennas is used. In this case, the distance between a transmitting antenna and a receiving one is estimated using measurements of the induced voltage in the latter. For a high operational range, the system makes use of resonant antennas tuned at the same nominal resonant frequency. The quality factors act as antenna gain increasing the amplitude of the induced voltage. The low-operating frequency is the key factor for improving robustness against nonline-of-sight (NLOS) conditions and environment influences with respect to other existing solutions. The realized prototype, which is implemented using off-the-shelf components, exhibits an average and maximum positioning error, respectively, lower than 0.3 and 0.9 m in an indoor environment over a large area of 15 m × 12 m in NLOS conditions. Similar performance is obtained in an outdoor environment over an area of 30 m × 14 m. Furthermore, the system does not require any type of synchronization between the nodes and can accommodate an arbitrary number of users without additional infrastructure.

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A Positioning System Based on Low-Frequency Magnetic Fields

10.36227/techrxiv.15081480 ◽

2021 ◽

Author(s):

Paolo Carbone ◽

Valter Pasku ◽

Alessio De Angelis ◽

Marco Dionigi ◽

Guido De Angelis ◽

...

Keyword(s):

Magnetic Fields ◽

Low Frequency ◽

Outdoor Environment ◽

Positioning System ◽

Induced Voltage ◽

Quality Factors ◽

Large Area ◽

Key Factor ◽

Loop Antennas ◽

Transmitting Antenna

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Practical High Resolution Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101256 ◽

1968 ◽

Vol 26 ◽

pp. 302-303

Author(s):

P. A. Marsh ◽

T. Mullens ◽

D. Price

Keyword(s):

High Resolution ◽

Magnetic Fields ◽

Low Frequency ◽

Resolving Power ◽

Careful Attention ◽

Electron Microscopes ◽

The Relationship ◽

High Resolution Microscopy ◽

New Facilities

It is possible to exceed the guaranteed resolution on most electron microscopes by careful attention to microscope parameters essential for high resolution work. While our experience is related to a Philips EM-200, we hope that some of these comments will apply to all electron microscopes.The first considerations are vibration and magnetic fields. These are usually measured at the pre-installation survey and must be within specifications. It has been our experience, however, that these factors can be greatly influenced by the new facilities and therefore must be rechecked after the installation is completed. The relationship between the resolving power of an EM-200 and the maximum tolerable low frequency interference fields in milli-Oerstedt is 10 Å - 1.9, 8 Å - 1.4, 6 Å - 0.8.

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