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

One part of the investigation into the disappearance of "Today" show host Savannah Guthrie's mother focuses on the missing woman's implanted medical device.

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.

December 8, 2011 (Rennes, France) — Remote monitoring of patients with dual-chamber pacemakers "was a safe substitute for conventional follow-ups, decreased the number of [clinic] visits, and enabled the early detection of important clinical and device ...

Two types of implantable cardioverter defibrillators can reduce the risk of sudden cardiac death with HCM. Pacemakers and implantable loop recorders also may be options.