Pacemaker EMR tolerance

[VK3ZAZ]

Hi
A local friend needs a pacemaker to regulate an irregular beat and he is 20 metres from my HF antenna
I am wondering if anyone has any technical experience with a pacemaker
what the emr rejection is and more importantly what hams responsibility is.

The web shows levels as low as 35 watts at 2 feet but nothing further afield.
It talks about CB power levels and ham power levels also metal detectors, microwaves all sorts of stuff.

Any input welcome and it goes without saying that the emr power levels we expose a fit human to may not be applicable to someone with a bionic heart
ACMA does not aaddress the question.
Telstra warn the public that entering an exchange may affect a pacemaker so don't do it.






2 cents

[VK5TM]

The only place to get the information on pacemakers and RF exposure limits/problems is directly from the manufacturer.

Information from elsewhere cannot be relied upon to be reliable or even correct and that includes the surgeon implanting the device.

[VK3ALB]

You may already know this but there are two reasons for concern with RF & pacemakers

RF interference to the pacemaker and localized tissue heating from the wire that stimulates the heart both of which are difficult to estimate due to factors such as body mass, field strength, type of pacemaker etc. In a previous life I worked in the medical field with MRI and the rule was pretty simple - a patient with a pacemaker and or other mechanisms for direct electrical stimulation was a no go. A blanket ban.

Some manufacturers warranted their products for exposure to typical fields inside the MR system but those field are much higher than the typical ham installation. The manufacturer of your friends pacemaker may have advice for you.

As you have already found the answer to your specific question is difficult to find. ARPANSA and FDA are two places I would look for more info. Good luck.

[VK4TI]

Terry is correct , actual site measurements against the pm specifications , should find emr is safe at less than 1/2 the 20m but you need to establish onsite , you know any one with the right gear ?
I have a regular visitor with a pm and he has no problem within the property but out of deference I try not to tx just in case when he is in the shack

[VK2HRX]

I work in the medical industry. Medical equipment has detailed statements re EMR in the respective product manuals, so as others have stated RTFM.

[VK4UH]

Hi all
Most modern implantable cardiac pacemakers run in a "demand" mode. They both electrically sense and pace the heart beat through the same cable into the heart muscle itself. In demand mode if the heart is beating within normal parameters then the pacemaker is like a politician - it lies and does nothing. If the heart beat is too slow or missed then the pacemaker drops extra pacing spikes into the rhythm and makes the heart beat electrically in the gaps. The concern is that if you are actually depending on extra pacing beats, few patients are all the time, and the pacemaker detects some RF or AC or electrical noise, exactly at that same time, then the pacemaker may misinterpret the noise as a normal heart beat and fail to drop in the pacing spike. The heart can slow right down, but wont stop. Current generation pacemakers have all sorts of low pass filter, DSP and FFT to minimise this problem.

The second issue is with magnetic fields. This is the main problem with MRI machines and the like. This is because pacemakers have a reed switch (or equivalent) in them that allows people like me to switch the mode the pacemaker is operating in by deliberately applying an external magnet. In operating theatres we use diathermy machines (read HF rig with linear) to pass large RF currents through the body to a cutting point to cut and coagulate tissue and stop bleeding. (Great for cutting bread, toasts it at the same time hi hi.) Seriously though, with a magnet applied all pacemakers are designed to default to a simple fixed rate mode and make the use of diathermy safe for the surgeons. The pacemaker then fires continuously at about 90 beats per minute and does not detect electrical signals at all. The risk now is that if an electrical pacing spike competes with a normal beat then the cardiac rhythm may be disrupted or worse case scenario causes the heart to fibrillate ( R on T phenomenon). -read life threating situation if not recognised.

This is OK in an operating theatre as you are fully monitored and we have defibrillators on hand but in the car or shack - not o good. The risks are very small and much of the advice offered is more about product liability than serious danger.

Anyone hams needing a pacemaker should not give up their licenses just yet! By all means discuss this with their cardiologist (who wont know anything about RF fields for sure) but will likely seek advice from the manufacturers to choose a device with the best immunity. Everyone should however be aware of the magnet issue.

***Most important*** Please read
This advice DOES NOT apply to anyone who has or needs an AICD. (Automatic Implantable Cardiac Defibrillator)
These devices are implanted into the body like pacemakers. They however are intended to defibrillate the heart with a large electrical shock if the normal heart rhythm is lost. They are used more and more frequently now in cases where patients have suffered cardiac arrest already or are at risk of doing so. These devices a specifically looking for higher frequency fibrillation signals from the heart and have a hair-trigger. They WILL fire if they detect some forms of interference.
These too have the magnet switch, which I again use to disarm the device during emergency surgery, but this must never happen outside the hospital as they may fail to re-arm and protect the patient when the magnetic field is removed - worse there is no warning that the AICD is disarmed and not functional.

When there is time before surgery both pacemakers and AICDs can be interrogated and programmed via an inductive loop coupling through the skin with the appropriate equipment

In general if your station complies with the current EMR requirements you can be confident of pacemakers being undisturbed..

I hope this may be of some use

Dr Kevin Johnston MB BCh, FRCA FANZCA - and VK4UH
Specialist Anaesthetist - in his day job

[VK2ZRH]

Thank you Kevin. Most appreciated.

When I had my AICD implanted in 2010, the morning after the operation, the Man from Medtronic came around to interrogate my implant, so I asked him about EMR issues. After he gave me the maker's product spiel, I then asked for full technical details on frequencies, field strengths, distances et al, and explained my background in radiocommunications engineering and ham radio. "Oh", he said, then asked for my email address. I subsequently received very comprehensive details via email, much more than the printed manual supplied with the product.

I know not to lift 12-inch speaker drivers above my waist.

I also know what it feels like when my heart goes into atrial fibrillation and the machine "takes over", without giving me a "belt".

Once again, thank you Kevin.

[VK3ZAZ]

Thanks
I am thinking about removing all low band wires that come down the tower from 75 feet and just staying on VHF and HF with yagis, no droopy wires near fences.

[VK2XSO]

I also know what it feels like when my heart goes into atrial fibrillation and the machine "takes over", without giving me a "belt".

So if you fall down at Wyong...
"Don't worry folks, we can reboot him! Anybody here got a 70cm and hand held?"

[VK3ZAZ]

Re the discussion about EMR and Pacemakers, thanks for all the input and advice.
ES VK4UH







watch this space.

[VK3II]

The recent pacemaker comments I found very interesting.
Five years ago I was “kitted up” with a pacemaker after I went very “QRT “ on a hospital stress test.

My pace maker is a Medtronics device
There are Medtronics warnings about not going near radio & tv transmission sites, arc welding, operating chain saws & working close to car engines when they are running.

At first I was apprehensive what would happen when I pressed the transmit button on the rig.
However there have been no noticeable side effects or problems with HF, VHF & UHF operating.
I have worked on linear power amps on the bench with caution.

My chain saw was taken apart & I fitted shielding around the ignition system, I leave car maintenance to others.
Arc welding is a spark transmitter with strong magnetic fields & I have not been “game” enough to try welding again.

Jim vk3ii

[VK3ZAZ]

QRT
Never thought of it that way
So is there a DX God up there?
Thanks for input.

Just walked around the house using my sub standard sniffer

Its a TRIFIELD Model 100XE
has meter and beeper and varible selectable scales
It sniffs
MAGNETIC to 0-100 mGauss
Magnetic to 3 Gauss
electric fields V/M and and micorwaves hot from 0.1 up to 1 watt per c meter


It states

absolute thresholds have not been established but biological effects may begin to be experienced at:-
3 milligauss AC magnetic (no mention of dc)
1 kilovolt/meter of AC electric field (power lines)
and 100 ucro watts per cm cubed. field density

[VK3AXH]

Re Pacemakers have a look at this site:- h-e.com/blog/bill-hammett/03-11-2011/pacemakers-and-rf-exposure

Steve i have had one of these devices for almost 5 years with no obvious effects. I did contact the manufacturer about arc welding and was advised that provided
you take care ie lowest current and leads going away from your body and operating at arms length things should be ok. I've done quite a bit since.

I also remember that some ham in the USA installed a pacemaker inside his HF linear amp with no apparent effect occurring. I would suggest contact to the manufacturer
might be a good starting point bearing in mind they won't say it's always safe. My unit is made by Medtronics who were quite helpful. I don't think I would place myself near
the HF antenna fields at Radio Australia but so far no problems with what I'm using at this qth.

Good Luck - Ian Mc VK3AXH

[VK4WDM]

When VK4KG applied to the Bowen council for permission to do RD on the Bowen beachfront we were asked about the effects of our RF emissions on pacemakers by the council WPHS manager (who was quite knowledgeable about EMR) and I posted a question on this logger. Dr. Kevin Johnston VK4UH provided the same info as he has done in this thread and I gave it to the WPHS manager who, after reading it, was happy to have our operation proceed. We did have a fenced off exclusion zone around the vertical antenna with appropriate signage which was twice the size required by the VK3UM calculator. We asked the manager if he would like to bring his RF meter and measure the RF but he was quite happy with the calculation (he was actually very impressed that "amateurs" did such things).

73

Wayne VK4WDM

[VK5RC]

A bit of data but only mobile phone
http://www.ncbi.nlm.nih.gov/pubmed/20180913

[VK3ZAZ]

Thanks for all the input.
VK3AXH thanks
I have been reading and can see that VK power limits es on yagis should not be an issue.
Linear amp and lo slung wires get the flick just to be safe.

So I err on safety and risk.
And moderate my operations accordingly.

WSPR seems safe as its continuous.

Softly softly.
Moving all gear over to metal shed and feedlines down inside of tower and grounded off at base of tower then into shack 80 feet from house.

[VK3ZAZ]

I did some tests today around property and relocate the delta loop away from house directly under tower and grounded off coax at tower base using ohmic connection and grounding

The bad news.

Sniffing around house using the trifield go no go RF box
all coaxes hot above safe limits for public exposure out to 1 metre from operating desk

mw/cm3 HIGH reading

metal window deep inside house about 2m sq hot at 50cm
A metal rail carrying a sliding door 2m long ditto
TV set in partners side of bedroom at 50cm
and main switch light at bedroom door.
I am inclined to think that an absolute distance from antenna has not factual bearing on eme limits due to re-radiaton.
measurements using a non ionising Radiation Monitoring device


MODEL 100XE in RADIO MODE
same box I use for WH&S requirements on TV sites as required by Policy of site owners.
Medtronics specs state 1KW erp 30M separation at short wave to 30 MHZ
Surgeon said person could climb your tower and have no effects

Trifield box readings seem to indicate that public exposure limits are being exceeded let alone someone with electronic monitor in their chest.
on this location using the following
40M 200 w pep
DELTA LOOP 25M down to 3M
Above shed roof line and 100 feet from house
Block 150m x 150m
https://www.google.com.au/maps/@-37.728 ... Aumr8g!2e0

SR Gregory
RF Worker
Broadcast Technician