My husband is near the end of battery life on his second pacemaker/defibrillator. He carries his manufacturer's card but has never been asked for it. He just tells TSA he has a pacemaker and they hand search him. His can be clearly seen/felt under his skin, even with a shirt on.
They can wand below the waist if they want but never do.

I was worried when we flew internationally but "pacemaker" seems to be universally understood and they know how to deal with it. I had obtained manufacturer's booklets in French and Italian but never needed to use them.