Re: Pacmakers and Tesla coils = bad??
At 20:14 13/02/2000 -0700, Terry Fritz wrote:
re implantable defibrillators,
>The people that have these are warned by
>their doctors what the jolt they give is like so they will be somewhat
LOL ....... some silly medico telling you that "if the thing goes-off while
you are awake, it will feel like being kicked in the middle of the chest by
a mule", in no way actually prepares you for this when it comes totally
"out of the blue" !
>This is especially important if they are driving or something
>(Mark mentioned that they would normally be unconscious, but perhaps that
>can be programmed).
First: IF (Implantable defibrillator) THEN NO DRIVING LICENCE !!!!
Ventricular rhythms which will trigger these devices fall into 2 groups:
1. Ventricular fibrillation (VF). This is a totally disorganized rhythm,
with no coordinated contraction of heart muscle and the patient is always
unconscious. This is rarely the trigger rhythm.
2. Ventricular tachycardia (VT). The main chambers of the heart beat too
quickly and out of sync with the feeding chambers. Usually associated with
a very low blood pressure and unconsciousness but NOT always ! Occurs
paroxysmally in some people, usually in the setting of atherosclerotic
heart disease but may even be familial.
Now, if you have an implantable defibbrilator, you want to be in the
Unconscious VT group ....... TRUST ME !!
>equipment that "talks" to these pacemakers may be able to detect and count
>the number of times they are affected.
Absolutely. Units record multiple parameters which can be downloaded to
the programming PC. Number of abnormal beats, episodes of arrhythmia,
action taken, fault states, etc. These devices are really quite "clever"
these days. For example, you can vary the programming so it doesn't
discharge until after 'x' beats of VT, so the person is more likely to be
>It would be nice if we could come up with a "safe" distance or some
>maximum EM level but there appears to be no such data that would apply to
>all manufacturers of pacemakers. It looks like the only thing we can go by
>now is "Keep pacemakers FAR away from any TC!"
Personally, I would NOT knowingly operate my coil in the presence of
someone with one of these devices and I am fully qualified to resuscitate them.
For the pro's, like kVA etc., the spectators are so far away that they are
probably safe. I suspect the back yard + the forgetful patient + the
unknowing enthusiast is the greater risk.
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