Affiliations: [a] Institute for Biomedical Engineering, University and ETH Zurich, Switzerland | [b] Federal Office of Public Health, Berne, Switzerland | [c] Cardiovascular Center, Cardiology, University Hospital Zurich, Zurich, Switzerland
Correspondence:
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Address for correspondence: Roger Luechinger, PhD, Institute for Biomedical Engineering, University and ETH Zürich, Gloriastrasse 35, CH-8092 Zürich, Switzerland. Tel.: +41 44 255 30 64; Fax: +41 44 255 45 06; E-mail: luechinger@biomed.ee.ethz.ch.
Abstract: Permanent magnets may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets have become widely available in recent years and are incorporated in various articles of daily life. We conducted an in-vitro study to evaluate the ability of NdFeB magnets for home and office use to cause interference with cardiac pacemakers and ICDs. The magnetic fields of ten NdFeB magnets of different size and shape were measured at increasing distances beginning from the surface until a field-strength (B-field) value of 0.5 mT was reached. Furthermore, for each magnet the distance was determined at which a sample pacemaker switched from magnet mode to normal mode. Depending on the size and remanence of individual magnets, a B-field value of 0.5 mT was found at distances ranging from 1.5 cm to 30 cm and a value of 1 mT at distances from 1 cm to 22 cm. The pacemaker behavior was influenced at distances from 1 cm to 24 cm. NdFeB magnets for home and office use may cause interference with cardiac pacemakers and ICDs at distances up to 24 centimeters. Patient education and product declarations should include information about the risk associated with these magnets.
