Kein Folientitel

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Interference of pacemakers by electromagnetic
fields - Presentation of of alerting device Dr.
Marcus Goetz MRC Systems GmbH, Heidelberg
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Agenda

• Effects on pacemakers/ICDs by electromagnetic
  fields
• Measures
• Curves from DIN VDE 0848-3-1 (German
  pre-standard)
• Presentation of alerting device

• More safety / better quality of life

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Electromagnetic fields

• What relevance do electromagnetic fields
  (electromagnetic pollution) have on pacemakers
  or ICDs?

• Pacemakers are equipped with a pulse generator
  and at least one electrode
• Pacemakers record an ECG (electrocardiogram)

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Hazards for pacemakers

• Interspersion of energy into the generator
  (possible up to about 10 kHz)
• Induction of voltage at electrode
• Misinterpretations
• External signals can sham pulses of the heart and
  inhibit a required stimulation
• External signals can sham false signals leading
  to false reaction of the pacemaker
• Modern pacemakers detect non-physiological ECGs.
  But they switch into a safety mode with constant
  frequency that can be too low in special
  situations.
• Uncontrolled simulations can take place in the
  vulnerable phase

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Consequences for patients

• Cardiac arrhythmia (ventricular fibrillation)
• Dizziness, inefficiency, loss of consciousness
• There is no long-term effect on the
  pacemaker/ICD. Once the source of interference is
  switched off or the distance is increased, the
  device will operate unimpaired (Exception Safety
  mode, component defect)
• In Germany there are about 300.000 pacemaker
  patients. The number of young persons is
  increasing.
• About 25 are in employable age

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Employment protection

• Prevention association Accident prevention
  directive BGV B11 Electromagnetic Fields
• 12(3) For persons with active or passive
  implants special measures are required to protect
  such persons against malfunctions. The employer
  has to inform the employees about possible
  hazards. Affected employees have to inform the
  employer, so that he can undertake the necessary
  measures.
• 14(7), Facilities with high static magnetic
  fields The employer has to take provisions,
  that for persons with active implants an
  individual decision about the activity can be
  made ....

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Agenda

• Effects on pacemakers/ICDs by electromagnetic
  fields
• Measures
• Curves from DIN VDE 0848-3-1
• Presentation of alerting device

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Measures of vendors

• shielded housing of pulse generator
• anti-parallel Zener diodes at the input
• through-capacitors
• intelligent programming (Sensitivity, frequency
  filters, refractory and blanking period)
• electronic receiving filters
• Safety mode (constant frequency mode) if ECT is
  conspicuous
• Warnings in documentation (limits for immunity to
  interference)

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Measures of physician

• low sensing sensitivity (prerequisite good
  contact of electrode to heart muscle)
• Programming (e.g. refractory and blanking period
  as long as required but as short as possible)
• Programming considers ECG signal and
  pacemaker signal.

Interference below sensing
Sensing
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Measures of physician

• Connection of electrode bipolar - unipolar (ICDs
  are always connected bipolar)

Bipolar short antenna
Unipolar long antenna
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Measures of person

• Stay away!
• The probability of interference strongly depends
  on the distance between source and pacemaker/ICD.

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Measures of person

• Analogy to water waves Energy is propagating in
  spherically, but it does not increase

High intensity
Low intensity
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Agenda

• Effects on pacemakers/ICDs by electromagnetic
  fields
• Measures
• Curves from DIN VDE 0848-3-1
• Presentation of alerting device

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Limits
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Limits

• graduated safety concept with 3 categories
• Category 0 appropriately stable (fulfil EN
  45502-2-1, that is oriented on the immission
  guideline EG519/99)
• Category 1 eingeschränkt störfest (95 of all
  pacemakers are not affected)
• Category 2 störempfindlich
• (Idea Marking of areas with interference
  sources)
• It is not a product standard, but an
  environment standard
• Body model -gt Re-calculation of external fields
  into voltages that are acting at the pacemaker
  (for different frequencies and signal types)

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Employment protection

• Requirements in factories
• Employee can work in accordance with
  qualification
• Evaluation of specific workplace (according to
  accident prevention directive)
• Mobility of employee / changing workplaces,
  environments
• Change operation modes of machines
• new machines
• Goal
• highest safety (for employer and employee)
• continuous control

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Agenda

• Effects on pacemakers/ICDs by electromagnetic
  fields
• Measures
• Curves from DIN VDE 0848-3-1
• Presentation of alerting device

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Curves
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Concept of device

• Principle Comparison of measured field strenght
  with curve from standard
• CardioMan supports
• in finding the minimal distance to hazardous
  machines, devices, etc.
• in proving the data given in manual of such
  machines, devices, etc.
• in recognising defective machines, devices, etc.
  that bear a higher risk

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Additional safety

• Facilities and devices with strong emission have
  to be indicated
• CardioMan provides additional protection, since
• not all facilities are indicated
• indication is not always visible
• you can not always see whether or not a device is
  hazardous
• you can not see electromagnetic fields

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Curves
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Design
display of hazard level
display for discrimination of different fields
battery level
loud-speakers
display of signal intensity
connector for re-charger
on/off switch
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Specification

• Technical specification
• acoustic and visual alert
• different detectors
• magneto resistive sensors (starting at 0 Hz)
• antennae with inductive and electric coupling
• full frequency range of 0 - 3,3 GHz
• simultaneous measurement of full range
• CardioMan is mobile
• very compact (hxwxd 77x68x20 mm)
• low-weight (weight 88g)
• rechargeable
• temperature range 5C - 50C

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Specification
Range 0-300 kHz 0.3-100 MHz 100-250
MHz 250-3,300 MHz detector 3 x
magneto antenna antenna antenna resistive
coupling magnetic magnetic / electric magne
tic / electric electric measured pu
nctual ca. 3 cm3 ca. 2 cm3 ca. 0,4
cm3 volume tolerance 0 / -6 dB 0 / -6 dB
0 / -6 dB 250-1,000 MHz 0 /
-6 dB 1,000-3,300
MHz -3 / -9 dB signal peak pe
ak peak peak detection