What the TSO did was, technically, an assault -- you were placed in fear of an imminent, unpermitted offensive contact. Should you sue? No -- aside from a few moments of fear, you have no damages.

However, next time something like that happens, call for a LEO immediately. The moron TSO could have sent you to the hospital or even killed you. Assault is assault and, once told that you had a pacemaker, he had absolutely no business approaching you with the wand -- waving that wand at you was no different than waving a knife or pointing a loaded gun. If it was me, I'd have pressed charges. At minimum, that idiot should be fired. I think he should have been arrested.