In addition to recording heart activity, pacemakers can also help document inactivity, such as confirming time of death. “After a patient has died, we interrogate the pacemaker to help determine the time of death or what may have happened. Sometimes we’re even called to the morgue to do this,” says Chu.

Nancy Guthrie’s pacemaker reportedly stopped syncing with her Apple devices predawn Sunday morning – as the Arizona sheriff leading the missing person case called a surprise press conference for late Tuesday morning.