EV safety for heart pacemakers

ex925 · **Posted:** Mon Dec 12, 2011 8:11 pm

Does anyone know of an affordable dc EMF meter, or a practical alternative method of measurement? Back-story is this...
The pacemaker manufacturer's representative advised:The acceptable machnetic field strenghts are for DC magnets 5 Gauss or 500 microTesla and for AC magnetic fields (50 Hz) 80 A/m or 100 microTesla..
I bought a "Tenmars TM-191" magnetic field meter. It measures from 30 to 300hz. That only covers ac. I am very reliably advised that for dc, accuracy from 0hz up to (maybe 200?)hz is essential. I also believe the above only covers EMF
Does anyone know how to measure RFI ? (especially, in what values to be safe for a heart-pacemaker?)
I would be very grateful for any advice
All the best
Ed

JonSpence · **Posted:** Tue Dec 13, 2011 3:05 pm

Most of the gauss meters that I can find are hand held, which should put you far enough away (hopefully). You might like to check this mobile phone app out and possibly email the author a question or two. Who knows, it might open up a new market for him.

http://dev.krugism.com/es_pro.aspx

It will only work on android mobile phones with a built in compass, which I don't have :cry:

I have no doubt that is works on DC though, as the sensor is designed to detect the earth's magnetic field. There is also the possibility that the sensor might saturate before you get to 5 Gauss.

ex925 · **Posted:** Tue Dec 13, 2011 4:01 pm

Very grateful
Have sent email
More soonest
Ed

ex925 · **Posted:** Wed Dec 14, 2011 9:00 pm

".....Ed,
Thanks for the inquiry and season's greetings to you too.
The Entity Sensor app will measure DC EMF from a background EMF of around 300 mG to about 1000 mG.
After 1000 mG the phone shuts down the magnetic sensor and reading are intermittent.
I wouldn't recommend the Entity Sensor app as a medical device, though.
The sensors on Android phones are meant to be used for the compass, and are not calibrated to measure an exact value.
The sensor should be used to measure the change in readings, not necessarily the actual Gauss measurement.
If you still want to use it, the standard Entity Sensor app measures EMF.
The "Pro" version does a lot more including recording EMF and audio, saving the values on the phone's CD Card.

Thanks,
Scott Krug....."

ex925 · **Posted:** Wed Dec 14, 2011 9:06 pm

So, still looking
My next step has been to ask the pace-maker manufacturer's technical dept. a few more questions

1 Could you suggest any other way to test for dc EMF in the critical range ?

2 How are such tests carried out on pacemakers ?

3 Do you have a test-pacemaker which could gain data by being placed in an EV ?
3.1 Have any EV manufacturers sought your advice ?
3.2 Might many pacemaker-users benefit from such data, as more EVs come into use ?

4 If all devices and cables in the EV were fully screened, would that be sufficiently safe ?
4.1 If so, is there a particular method of testing the results of screening to ensure safety ?

5 Has your company tested EVs for pacemaker safety in re EMF and RFI ?

6 Is it true that the critical frequency for dc EMF is from 0hz upwards ?

If anyone on here can help, I would be grateful
Ed

jonathan jewkes · **Posted:** Fri Dec 16, 2011 5:23 pm

Presumably you are investigating this because you, or someone who will be using your EV, has a pacemaker.
The other approach is to ask what would happen to the person if the magnetic field did in fact affect the pacemaker.

Ask the manufacturer's rep - Would the magnetic interference would cause the pacemaker to send out an unnecessary pacing stimuli, or pace too frequently? Or would it temporarily stop it functioning? Or would it completely alter the pacemaker settings? (In the pacemaker clinics they can alter the settings by holding an external device on your skin close to the pacemaker - I don't know what type of signal this uses to communicate with the pacemaker).

Ask the person's doctor or pacemaker clinic why they have got a pacemaker, and what would happen if the pacemaker ceased to function and their pulse became very slow. Would they just feel tired and a bit breathless? Or would it lead to dizzy spells or blackouts? (These are the two commonest symptoms for which pacemakers are inserted. The heart does not stop completely if the pacemaker is not working). However, excessively frequent pacing stimuli could perhaps be more dangerous than having none at all.

JonSpence · **Posted:** Fri Dec 16, 2011 7:13 pm

jonathan jewkes wrote:

Presumably you are investigating this because you, or someone who will be using your EV, has a pacemaker.

I confess that I assumed otherwise. The magnetic fields in the passenger compartment will be low. RF could be higher than normal unless significant effort is made, but most of us would make the effort so that radio's, phones and SatNav could function.

I assumed the concern was working on the EV. Motors have HUGE magnetic fields within them, mostly contained. PWM control comes very close to early spark gap radios for RF, so there could be a danger there while working, unless you screen the cables (as is becoming standard in industry).

ex925 · **Posted:** Fri Dec 16, 2011 8:18 pm

Gentlemen, thank you both for your information, which has clarified my understanding
The pacemaker in question is unusual in that the user has no unaided heartbeat
Medical advice is absolutely that any effect would probably be fatal

More soonest

Ed

ex925 · **Posted:** Wed Dec 21, 2011 7:28 pm

Sitrep

We are now advised that no EV can now be considered safe for this user

Medtronic, (pacemaker manufacturer) have sent some additional information
They will review the results of any RFI and EMF readings we gain from various EVs

I propose to write to all EV manufacturers, seeking their advice re pacemakers

Any suggestions or comments would be appreciated

More soonest

Ed

JonSpence · **Posted:** Thu Dec 22, 2011 3:08 pm

ex925 wrote:

Sitrep
We are now advised that no EV can now be considered safe for this user

I do hope that everyone realises that includes electric trains. They are after all a VERY powerful EV.

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EV safety for heart pacemakers

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