I have done some studying on this. Evidently the older mig welders were not as high frequency as the newer ones are today. And so they're saying that it would be safer to use the older migs because of this. And to stay away from The High Frequency mig welders. And you try to do your welding as far away from your body as you can. Also stay under 130 amps.
But they say TIG, Arc and the plasma cutters are definitely no nos.
I'm talking about if you have a defibrillator not if you have just the heart monitor. Cuz there are differences there.