a lot of info is available if you google "arc weld" + pacemaker.
here's a sample:

PACEMAKER PRECAUTIONS

# Do not arc-weld. Electromagnetic fields may interfere with your
pacemaker function.
# Do not do mechanical work on a running car or engine. Small
electromagnetic fields are present.
# If you are to undergo magnetic resonance imaging (MRI), inform the
doctor or medical staff that you have a pacemaker, because this
procedure can pose problems for your pacemaker.
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Sounds like arc welding is a process you'd best avoid.

Good luck,

Red