Re. pacemaker & TC's (fwd)

---------- Forwarded message ----------
Date: Mon, 15 Dec 97 11:35:18 EST
From: Gary Lau  15-Dec-1997 1156 <lau-at-hdecad.ENET.dec-dot-com>
To: tesla-at-pupman-dot-com
Cc: lineman23k-at-aol-dot-com
Subject: Re. pacemaker & TC's

>From: LINEMAN23K <LINEMAN23K-at-aol-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: pacemaker & TC's
>I am just about to smoke test my first coil and would like some saftey info.
>My Mom has a pacemaker and I don't want to endanger her health.  Is there a
>safe distance she can watch from or should this be something for her to see on
>Rusty Duncan

I had the same concern and did some web searching, looking for
"pacemaker" and "Microwave".  I turned up an article entitled
"Electromagnetic Interference and Medical Equipment" by the U.S. Army
Center for Health Promotion and Preventive Medicine.  It discussed (in a
cursury manor) the impact of interference of various devices on medical
electronics.  At the bottom was both Email and phone numbers.

The Email address bounced but I did get a live person at the phone
number.  I described my question, that I had a Tesla coil that generates
3-4 foot sparks and was concerned with the effects on nearby pacemakers.
He understood what Tesla coils were and said that as long as people were
not in direct contact and at least a meter (!) away, he thought it was
unlikely to have any effect (but that he would STILL keep one eye on the
pacemaker user).  He also said that only the earliest pacemakers were
succeptable to such interference, newer models having better filters.
The article was interesting in that it stated that microwave ovens pose
no hazard to pacemakers.  I saved the article (attached) but have since
lost the URL.

Gary Lau
Waltham, MA USA

                Electromagnetic Interference and 
                       Medical Equipment

                 CHPPM Fact Sheet # 24-004-0595

Recent reports of deleterious effects on electronic medical devices,
by electromagnetic energy, have caused concern among health care
providers. One such report in Compliance Engineering (Reference 1)
enumerates various problems with medical devices allegedly caused by
conducted and radiated electromagnetic energy-as well as electrostatic
discharge and static-magnetic fields. Electronic medical device
problems attributed to electromagnetic interference (EMI) include
device failure, loss of control, and erratic operation - any of which
could circumstantially threaten someone's life.

Electronic medical devices are increasingly subjected to
electromagnetic emissions from sources brought into the hospital
environment such as cellular telephones. radios, and some paging
systems. Both hospital staff and visitors have inadvertently caused
EMI problems while using these sources within several meters of
susceptible devices~ For example, In Scandinavia a cellular telephone
caused an infusion pump to switch to the maximum infusion rate while a
potent drug was being administered (Reference 2).

Manufacturers of artificial pacemakers have long identified EMI
susceptibility problems. They subject pacemakers to susceptibility
tests to ensure that the device is adequately shielded against
electromagnetic energy levels one would expect individuals to normally
encounter. These efforts have resulted In lifting all restrictions
regarding proximity of pacemaker users to microwave ovens. Still,
these individuals are restricted from certain areas of hospitals where
electromagnetic fields could interfere with pacemaker operation-such
as physical therapy clinics where radiofrequency (RF) diathermy is
used, and MRI facilities.

Susceptibility testing of medical devices is not regulated in the
United States, and manufacturers of medical devices are specifically
exempted from compliance with the Federal Communications Commission
(FCC) emission standards. Therefore. manufacturers have not been
compelled to perform susceptibility test~although many have
voluntarily done so. Yet without standard test methods, medical device
manufacturers may use minimal test criteria and reduce their
production costs at the expense of susceptibility.

The majority of medical equipment now in use in hospitals throughout
the United States has not been reviewed by the FDA for susceptibility.
Consequently, much of the electronic medical equipment presently in
use may either cause EMI or be susceptible to EMI. Recently, the Food
and Drug Administration (FDA) has expanded their efforts to require
susceptibility test data from manufacturers applying for FDA approval
of certain medical devices.

The American Society for Hospital Engineering has published several
suggestions for reducing the risk of EMI problems associated with
electronic medical equipment (Reference 3). These suggestions are
provided below:

         Verify that the FDA has examined the EMC test data from the
manufacturer prior to acquiring new equipment.

         Keep potential sources of EMI away from susceptible devices.
Some hospitals  already restricted the use of cellular telephones and
radio transmitters In  containing life-sustaining equipment (e.g.,
Intensive Care, Cardiology, Surgery,  Dialysis).

         If induced RF currents from unshielded cables are causing
EMI, then rerouting the cables or substituting shielded cables may
eliminate the problem.

         Analyze the building's electric wiring and grounding systems
for conducted RF currents. Isolating susceptible devices from these
systems is a potential solution to conducted interference problems.

We encourage all health care practitioners to report incidents of
suspected EMI to their facility engineers. The FDA regulations require
users of electronic medical equipment to report incidents of equipment
failure that may have caused or contributed to a death or serious
Injury. The Radiofrequency Program of the U.S. Army Center for Health
Promotion and Preventive Medicine is available to assist in
identifying and solving possible EMI problems.


1.        Silberberg, J.; Compliance Engineering, Vol.10, No.5, Fall
1993: "Performance Degradation of Electronic Medical Devices Due to
Electromagnetic Interference.

2. Bostrum, U.; Clinical Engineeringg Update. No. 10, November 1991;
"Interference from Mobile Telephones - a Challenge for Clinical

3. American Society for Hospital Engineering of the American Hospital
Association. (August 1994). Healthcare Facilities Management Series. 
Electromagnetic Interference: Causes and Concerns in the Health Care

Send comments and correspondence to:

     Radiofrequency/Ultrasound Program
     U.S. Army Center for Health Promotion and Preventive Medicine
     Aberdeen Proving Ground, MD 21010-5422

     DSN 584-3353 or Commercial 410-671-3353
     email: mchbdsr-at-aeha1.apgea.army.mil
Send comments and correspondence to:

     Radiofrequency/Ultrasound Program
     U.S. Army Center for Health Promotion and Preventive Medicine
     Aberdeen Proving Ground, MD 21010-5422

     DSN 584-3353 or Commercial 410-671-3353
     email: mchbdsr-at-aeha1.apgea.army.mil