Technical Query
Jack Rae of the Carlisle & District panel would like help with the following:
On another web-site, dealing with construction of model locomotives etc, a question was asked if pacemakers were susceptible to compromise if the wearer was doing work such as electric welding. No definitive answers were forthcoming – most seemed to be based on either supposition or at worst myths. Maybe one of our members has first hand experience in the design of such devices and can provide a definitive answer.
Many thanks and kind regards
Jack Rae Carlisle & District panel
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Many thanks to all for their kind replies.
The salient points have been forwarded to the relevant forum site for consideration by the original enquirer
Jack
http://www.medtronic.com/rhythms/downloads/3071ENp6_Saws_online.pdf
and
http://www.aws.org/technical/facts/FACT-16.pdf
Should give you as close to a definitive fact based answer as you are likely to get.
There is a “definitive answer” which is to obey the manufacturers recommendations!
Suppliers of pacemakers recommend users to avoid strong magnetic fields particularly mentioning arc welders and airport scanners, and not keeping your mobile phone in your left breast pocket. I have used a small TIG welder and a small spot welder with no ill effects. However, I think my pacemaker was temporarily disabled some years ago when I passed through a scanning arch that could not be avoided. (In a high security prison). I subsequently felt faint and found my pulse rate was slow and erratic for about twenty minutes – whilst I sat down and was given a cup of tea. If it was an issue with the pace maker, and I cannot be certain, it recovered OK but I now insist on not going through the scanners at airports and always get frisked instead.
Pacemakers communicate via a wireless link for programming and reporting back a history of heart activity. I do not know if it is this that makes them vulnerable or the fact that they have wires attached that could act as an aerial and might generate an unacceptable voltage in the presence of a powerful AC field.
Whatever the case one can but marvel and respect the technology that can keep your heart beating for up to eight years without a change of battery.
“Electric Welding” covers a huge range of possibilities. However, most electric welding involves very large electric currents, the passage of which will generate large magnetic fields which will induce currents to flow in other nearby conductors. As the electric arc results in broadband modulation of the supply current, it will result in magnetic fields with a wide range of frequencies and the induced current will thus also be broadband “noise”. Whilst the pacemaker does have input filters – they weren’t designed to cope with this signal to noise ratio. There are exceptions. Some welding, eg TiG, can involve very low currents (of the order of a few amps). Which doesn’t present the same degree of risk as, say, a 300A arc welder. Additionally, some welders have an open circuit voltage way above the “extra low voltage” limit considered safe, when it comes to electric shock. Whilst the shock joules that result are probably not going to cause problems for a normal healthy adult – those with pacemakers are considerably more at risk. Some welders also superimpose a relatively high voltage, high frequency, low energy “arc initiation” signal on the electrodes. Again, the joules involved are not enough to harm a healthy adult, but those with pacemakers are different. Finally, many welders are imported models built under dubious safety and reliability standards. Although a standard 30mA trip should be enough protection in the case of a fault, those with a pacemaker are at greater risk.
So, I’d say – if the welding is low current TiG with quality equipment in dry conditions – it would probably be ok. Otherwise – no. I’ve received shocks (from other people’s welders) often enough not to want to risk one, if I had a pacemaker.
Maybe this is too obvious – how about contacting the manufacturers of the pacemaker? If you don’t know, you could try one of the big companies (e.g. Medtronic). Alternatively, the medical physics department of your local general hospital (if they still have one) may be able to help.
Having seen a Lorry battery explode (spraying acid over the inside of the battery box) when an arch (stick) welder was being used on the chassis, I would suggest that if a pacemaker has a battery which I belive it has, then I would say stay away from anything liabe to give an electric shock, eg Arc or Mig Welders as the battery in the pace maker may not like it.
Hi, a quick check suggests that it could have an effect, if you have an attack at the time, but there is no long term damage to the pacemaker itself! Search on the Internet for”pacemaker welding” and read the various articles.
Regards
Derek