When I got my ICD (Boston Scientific) in 2017 I asked about welding. The factory rep who I got to talk to while I was in the hospital said when I get ready he would come to my shop and check me out on welding. I had him come out and he disarmed the ICD and draped a receiver over my shoulder that was hooked to a laptop. I did TIG steel, TIG aluminum, Stick arc, MIG steel, MIG spoolgun aluminum and Plasma cutter. I did these at my normal levels doing all the right things like not draping the cords over my shoulder, keeping the welder itself at a distance, clean starts etc. Then we repeated these processes but this time I did it at max current (200A), leaning in close, cords over shoulder and stutter starts. No problems in any of these.
Before we started he told me that I need to know a couple of things. First was that the way the ICD works is that it is looking for a fast frequency. when it gets this fast frequency either real or fake (welding?) it performs four tests the first test is for appx. six beats IIRC. If it passes that test (fast frequency) then it tests again for six beats. If still fast it then monitors for four more using a more stringent set of parameters. then it does it again for four beats. If all four of these "gates" of whatever are satisfied that a fast 'heart-beat' exists then it charges and shocks when the charge cycle is complete.
He also said that there is no timing on when the shock hits, It just dump after it fully charges. He said what I need to know about this is that there a something called the "window of vulnerability". This is the ascending part of the T wave. If the shock happens to land on this few millisecond of time then it will PUT YOU INTO V FIB! Then the ICD runs all these tests again and shocks you the second time to restore natural rhythm. this is why some people fall out after getting an accidental shock like an electrician or a baseball player getting hit in the chest and dying. It now makes sense why they tell you if you have a problem stiking an arc, just wait 10 seconds or so and start again. This interupts the testing algorithm of the ICD.
What I got out of all this is the ability to tell my neighbor I can't weld on his POS lawnmower for the fifth time but I can still do my own projects.
I talked to some others and they tell me about the twisted leads, use dry gloves, don't stand in water, stretch out the cables to keep the welder at a distance etc. I have done welding since then and have had no problems.
My advice would be to push the factory rep to come out and test you doing your stuff. It was a BIG peace of mind to me. Don't take my word for it. YMMV.
