I gots me one of those (pacemaker)...and ifin yours is goin off, y'all best call the cardiologist and get them to figger out why for ya.........( all said "tongue in cheek"..except the pacemaker part LOL)
Maybe look at page 35 and 36 of the manual. In the front when it talks about turning the scanner on it has a note. See setting alert tone. Might be all together. A call to the Doctor might not be a bad idea. Just to make sure what is causing it to set off the pacemaker.