I discuss this matter in my book parasite Zapping and the Zapper.

Basically, some Stainless steel alloys contain either or both Nickel / Chromium which are classified as tissue irritants and may possibly cause local tissue irritation / cardiac irritibility or other problems.

However, this aside, my dad is 85 and has used the zapper for several years while having stainless cardiac stents without any noticible problems.

My suggestion is to be aware of the possible difficulties and choose wisely.

Did you by ant chance get an answer. I also have stents and would really try zapping.
Thank You