As the search for Savannah Guthrie's mother, Nancy, continues, a cardiologist explains how pacemakers work and if they can be used to track a missing person's location.

Unconfirmed media reports say Nancy Guthrie's pacemaker stopped syncing with her Apple devices. Here's what that means.

Information about Nancy Guthrie's pacemaker helped authorities piece together a new timeline in her kidnapping. Can the devices track you?

Dr. Srihari S. Naidu speaks with Parade to answer all our questions about pacemakers.

Nancy Guthrie’s 2 a.m. pacemaker spike on the day she vanished could mean that the elderly woman was involved in a heart rate-surging struggle with her possible captors, a lead cardiologist speculated Thursday.

A pacemaker is a small, battery-powered device that controls the heartbeat. Our heartbeats are controlled by a highly efficient, biological electrical system that ensures our heart steadily pumps blood to the rest of the body. But sometimes — due to age ...