title: Interference of low frequency magnetic fields with implantable cardioverter-defibrillators.
abstract: OBJECTIVE
  The aim of this study was to find the electromagnetic interference (EMI) thresholds for several commonly used implantable cardioverter-defibrillators (ICD).
  
  
  METHODS
  Seventeen ICDs were exposed to magnetic fields with different intensities produced by the Helmholtz coil system. Sinusoidal, pulse, ramp, and square-waveforms with a frequency range of 2 Hz to 1 kHz were used.
  
  
  RESULTS
  ICD malfunctions occurred in 11 of the 17 ICDs tested. The ICD malfunctions that occurred were false detections of ventricular tachycardia (6/17 ICDs) and ventricular fibrillation (3/17 ICDs), false detection of atrial tachycardia (4/6 dual chamber ICDs) and tachycardia sensing occurring during atrial or ventricular refractory periods (1/17 ICD). In most cases, no interference occurred at magnetic field levels below the occupational safety limits of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Nevertheless, some frequencies using sine, ramp or square waveforms did interfere with certain ICDs at levels below these limits. No EMI occurred with any of the ICDs below the ICNIRP limits for public exposure.
  
  
  CONCLUSIONS
  Evaluation of EMI should be part of the risk assessment of an employee returning to work after an ICD implantation. The risk assessment should consider magnetic field intensities, frequencies and waveforms.
authors: Safe New Technologies, Finnish Institute of Occupational Health, Helsinki, Finland. maria.tiikkaja@ttl.fi
authors: Maria
authors: M
authors: Tiikkaja
authors: Tommi
authors: T
authors: Alanko
authors: Harri
authors: H
authors: Lindholm
authors: Maila
authors: M
authors: Hietanen
authors: Lauri
authors: L
authors: Toivonen
authors: Juha
authors: J
authors: Hartikainen
mesh_terms: D017147:Defibrillators, Implantable; D004868:Equipment Failure; D060526:Magnetic Fields