Pacemakers and welding

Here's a very good article on this subject.

Cardiac pacemakers are electronic devices with sensing circuits which detect small electrical signals from inside the heart. Pacemakers may detect extraneous electrical signals from other sources. The pacemaker can incorrectly interpret these signals as heart activity, which may inhibit the pacemaker. The result could be no output pulse or asynchronous pacing. Asynchronous pacing means that there is no coordination between the heart and the pacemaker.

If you have a St. Jude Medical pacemaker and use or are in close proximity to an electric welder, you shouldn?t have any problems. However, this doesn?t mean that there is a total absence of the effects of welding interference on pacemakers. Any problems caused by radiated interference will end when the arcing ends.

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Reply to
Ignoramus6829
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"Ignoramus6829" wrote

Any problems

Or the wearer hits the deck.

Steve

Reply to
SteveB
[snip]

Good description.

The leads to the heart likely will act as an antenna...picking up the welder's RF emissions and feeding them to the digital circuitry to affect the internal processor.

I really suspect that during testing a pacemaker is NOT subjected to this intensity of RF emissions...a cell phone or a microwave likely...a welder not likely.

If I had a pacemaker, I would not be welding.

TMT

I don't know if welding with the pacemaker is good or not, any way.... I know of an old old guy who has a pacemaker and puts his spare arm across his chest as a "shield" when he MIG welds - obviously this may be against what the Dr recommends and may not be safe.......

I've some experience in the testing of electronic devices for EMI compliance. There are different standards for different classes of device - ie kids toy v's electric wheelchair v's pacemaker. For devices needing a degree of immunity from EMI the tests involve pointing an antenna at the device and irradiating it with different levels and frequencies of RF radiation. How this level of RF compares with that emitted by a TIG I don't know. I'd be more worried about the high magnetic fields around a spotwelder.

Reply to
K Ludger

It was not a good article at all. I've been researching this a bit, have a consult appt on Friday with a doc that will install an ICD in my bod. I damned well intend to continue welding when I want to, and my research indicates that this won't be a problem. This is not an abstraction for me.

Getting old is not for sissies.

Reply to
Don Foreman

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Similar precautions apply to working on car engines and possibly other activities generating electromagnetic fields. I have always been interested in the effect of amateur radio on pacemakers. The research I did, some with help of pacemaker company representatives, was rather inconclusive. Personally I would avoid a ham shack in operation having seen RF sparks on metal objects otherwise not connected to anything, light bulbs connected to a piece of wire lit up by a KW with a key down, neighbours' lamps turned on and off and many other amusing phenomena.

The message I think is that you *can* have problems while arc welding, be it a St. Jude, Medtronics or any of the others. One problem not mentioned is re-programming the pacemaker which may enter the back up mode and not revert when the EM field is gone. Some may not notice it, some may become symptomatic.

A similar situation arises during surgery when the surgeon uses electro-cautery to stop bleeding. The usual procedure in this region is to convert the pacemaker pre-operatively to a fixed output that cannot be inhibited and crank up the voltage. The pacemaker is checked and reprogrammed carefully back to the original settings after the surgery. This is clearly not an option while welding :-)

Oh, and I would not expect a discussion with your MD to provide any more information than what is in the article. Unless he works in a major centre and does nothing but pacemakers. Even then I have my doubts...

Reply to
Michael Koblic

What the article says is that welding may interfere with a pacemaker, but only temporarily while magnetic fields are present. It mentions the 400A limit etc. I cannot see why you think that it says that welding is not allowed with pacemakers.

Reply to
Ignoramus13440

Don,

I'm glad you are not impressed with the plethora of advice coming from RCM re. RF and pacemakers. They mean well but most of them don't realize you've probably forgotten more of the subject than they can know. Those that would caution you about RF are oblicious to the more dangerous radiation coming from their monitors and microwave ovens. Much has been written about RF from cell phones and the jury is still out on that issue. IMO, the danger from a cell phone pressed up against one's head is far greater than that from a welding device - this due to both frequency and the isolation due to proximity. Ask your Doc.

Bob Swinney

It was not a good article at all. I've been researching this a bit, have a consult appt on Friday with a doc that will install an ICD in my bod. I damned well intend to continue welding when I want to, and my research indicates that this won't be a problem. This is not an abstraction for me.

Getting old is not for sissies.

Reply to
Robert Swinney

What is the underlying condition that needs the ICD? My father is looking at more heart work after they did a bunch already. I told him to talk to the doc's about an ICD and see what they say. They already have ablated some areas and he's on enough meds to qualify as a pharmacy...

Reply to
Steve W.

RF and pacemakers.

of the subject than

more dangerous radiation

RF from cell phones and

pressed up against one's

frequency and the isolation

You are confusing two entirely unrelated things - The effect of RF radiation on biological items (humans), and the effect of RF radiation on electronic devices (pacemakers).

Reply to
Pete C.

RF and pacemakers.

of the subject than

more dangerous radiation

RF from cell phones and

pressed up against one's

frequency and the isolation

Also, re the cell phone thing - Most of what has been written about them has debunked the few baseless fear mongering pieces that have received media attention. The simple fact is that the

Reply to
Pete C.

Pete C sez:

"You are confusing two entirely unrelated things - The effect of RF radiation on biological items (humans), and the effect of RF radiation on electronic devices (pacemakers)."

On some order of magnitude, electromagnetic radiation of sufficient strength to adversely effect an electronic device, such as a pacemaker, would likely be enough to have very severe effects on human tissue. This because "radiation hardness" is a design spec of electronic components. Rad Hard is not generally specified except for components used in military hardware. You can bet it is considered in the design of pace makers.

Bob Swinney

Reply to
Robert Swinney

I didn't say I think that. I merely think that the article is rather general and vague. A 400A "limit" is absurd because there are many other relevant variables, including the physical (geometric) arrangement of the welding leads. More relevant limits would be magnetic field parameters (H or B) and their first time derivatives in the region of the ICD.

Reply to
Don Foreman

LOL.

Reply to
Don Foreman

I'm not sure. The doc's recommendation is based on his reading of a recent MRI. I'll know more on Friday.

Reply to
Don Foreman

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He does work in a major cardiac center, he does specialize in ICD's and there are at least two major mfrs of ICD's here in town ... so he just might know more than one might expect.

Reply to
Don Foreman

This will probably invite jokes, but I don=92t mean to be flippant and I hope you can continue to weld safely:

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Reply to
guillemd

Not a solution. These things don't block RF below about 100Mhz, far above the fat part of a TIG welder's emissions.

I also suspect they are useless at their stated frequency without a good RF ground, which isn't trivial.

EMI shielding is an enormously complex subject. I know from personal experience that improvised shielding is almost always useless and can only be made to work with measurements and tweeks.

Reply to
Jim Stewart

I am sure the manufacturer of the welding equipment has information about the radiation levels and frequencies that the welder radiates.

Interference is somewhat a matter of luck of having the output freq. and something in the ICD resonate on that same freq. The watt desities of radiation from a welder are not as much as you might think and would most likely occur at the low end of the spectrum. You would more likely have problems from electron through your body by touching the ground and the welding electrode and having the current flow across your chest.

John

Reply to
john

"Rad hardness" has nothing to do with RF. It's for nuclear radiation. Also, chips typically do not have a spec for EMI/RFI. Damage or disruption is almost entirely dependent on the signal levels picked up by the interconnect structure wired to them, which is beyond the manufacturer's control. The most you will get is an ESD rating.

For the issue at hand, the most likely problem is energy picked up by the sense leads causing false triggering or erroneous readings. Modern pacemakers have fairly sophisticated algorithms for sensing when to shock, how much, etc. that could be confused by noise picked up from a strong interference source.

Doug White

Reply to
Doug White

Witht that description it is his job to know it *all*...

Reply to
Michael Koblic

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