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Re: Pacmakers and Tesla coils = bad??
Presumably, though, the pacemakers are designed so that if the field
doesn't exceed the standard RF exposure guidelines (and probably a couple
of orders of magnitude greater) that there wouldn't be any problem. The TC
issue then boils down to whether you meet the ANSI RF exposure guideline.
Recalling from previous discussions that TC's make pretty bad antennas, the
fields, once you are a few meters away, are quite low.
Not that we shouldn't care, but it might not be that big an issue. Does
anyone have any specs on EMI/EMC requirements for implanted medical
devices?
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Pacmakers and Tesla coils = bad??
> Date: Saturday, February 12, 2000 11:48 PM
>
> Original Poster: Mark Finnis <mefinnis-at-medicine.adelaide.edu.au>
>
>
> This is a little long, but please indulge me !
> The note at the end could be placed in the Safety FAQ ??
>
> At 05:48 11/02/2000 -0700, Terry Fritz wrote:
>
> >It appears today's modern computerized RAM, ROM, programmable,
> >microprocessor, built in defibrillator, etc. pacemakers may be
"confused"
> >by things like arc welders, diathermy, x-ray, MRI, Shoplift detectors,
> >airport security, etc. equipment that puts out powerful RF or magnetic
> >fields.
>
> This is true, to a point.
>
> >My first thought was that Tesla coils beat all those interference
sources
> >easily!!
>
> No question !
>
> The newer pacemaker units are programmed by inductive coupling. You have
a
> PC driven programming unit which attaches to a coupling probe which is
> placed over the pacemaker (in the person who is wide awake) and the unit
is
> re-programmed accordingly while you have a chat to the patient.
>
> We usually test the defibrillators with people under light general
> anaesthesia, 'cause the jolt is a little unpleasant awake. The unit is
> capable of *inducing* VF (ie a cardiac arrest) in the patient, so that
the
> units response can be checked. In life it only goes off when the person
> has an arrest (therefore is unconscious) but to check this awake would be
a
> little nasty. A TC could easily "instruct" the unit to do this in error
!!
>
> CLEARLY, both of these devices have tuned receiving coils which are used
> for in situ programming. Both may actually CAUSE arrhythmias in the
heart
> and close proximity to a TC would be highly inadvisable.
>
> IMPORTANT NOTE: Virtually all of these devices have an in-built safety
> feature. Placing a moderately powerful magnet over the control unit
> (usually just under the clavicle, or on the side of the chest/abdomen)
will
> cause them to revert to a standard pre-programmed safety mode. This will
> however revert once the magnet is removed.
>
> For example, all operating theatres in Oz (and USA I believe) have
> appropriate magnets in the top draw of the anaesthetic machine for
exactly
> this reason.
>
> >I would think a Tesla coil would be an excellent test bed for pacemakers
> >and their susceptibility to nasty electromagnetic fields. It would have
to
> >be a lab grade device that was consistent. Perhaps a few million bucks
> >from a government grant would help out defining how a Tesla coil could
be
> >used to rate such devices... Apparently, the new pacemaker's ability to
> >deal with such emitted energy sources is a very big deal...
>
> Now I was wondering what my next research project could be ;-)
>
> Mark
>
>
> ___________________________________________________________
>
> Mark Finnis Hm: 61 8 8431 2889
> Staff Specialist Wk: 61 8 8222 4000
> Intensive Care Unit Fax: 61 8 8223 6340
> Royal Adelaide Hospital Mbl: 041 2324268
> www.health.adelaide.edu.au/icu
> ___________________________________________________________
>
>