New paper from Northeastern team shows how pacemaker signals could aid missing-person searches

Research inspired by the search for Nancy Guthrie finds that Bluetooth-enabled pacemakers can be identified from nearly a football field away, but they are not GPS trackers

When Nancy Guthrie disappeared from her Arizona home in February, one detail attracted unusual attention: The 84-year-old mother of “Today” co-host Savannah Guthrie reportedly had a pacemaker. Could signals from the implanted device help investigators find her?

A new paper co-authored by Northeastern University researchers offers a carefully qualified answer: potentially, but only under the right conditions.

Published online September 16,  2026, in JAMA Cardiology, the study found that a common model of Bluetooth-enabled pacemaker could be reliably detected from 90 meters away, approximately the length of a football field. Researchers occasionally received its signal from 100 and 120 meters. The results establish that pacemakers can be detected at much greater distances than the approximately 10-foot range associated with routine patient monitoring.

That does not make a pacemaker a GPS tracker. It does, however, suggest that specialized equipment could help searchers determine whether a particular device, and potentially the person carrying it, is within a defined area.

“We observed Bluetooth-enabled pacemakers to broadcast identifiers that can be detected and associated with a specific device at distances substantially greater than those used clinically,” the researchers conclude.

The Northeastern members of the research team are Hui Zhuang and Kevin Fu, whose affiliations span the university’s Department of Electrical and Computer Engineering, Department of Bioengineering, Khoury College of Computer Sciences and Archimedes Center for Healthcare and Medical Device Cybersecurity. They collaborated with researchers from Beth Israel Deaconess Medical Center, Harvard Medical School, MIT and Harvard Law School.

Listening for a brief Bluetooth signal

Many modern pacemakers communicate wirelessly with a bedside monitor or a manufacturer’s smartphone application. That connection allows information about the patient’s heart and the performance of the device to be sent to clinicians.

Even when a pacemaker is not actively connected to such a system, the researchers found that it periodically announces its presence using Bluetooth Low Energy.

The team tested three Medtronic Azure XT DR MRI SureScan pacemakers, the model selected based on public assumptions about the device involved in the Guthrie case. The devices were tested outside the body and placed at increasing distances from a high-gain directional antenna.

Approximately once every three minutes, each pacemaker opened a short “advertising window” lasting just 400 to 500 milliseconds. During that fraction of a second, the device transmitted Bluetooth packets containing a fixed identifier known as a media access control, or MAC, address.

That identifier allows a receiving system to distinguish one device from another. In practical terms, searchers equipped with the appropriate antenna and receiver might be able to sweep an area for the identifier belonging to a missing person’s pacemaker.

The experiment did not require the manufacturer’s bedside monitor, a paired smartphone or the clinical programmer normally used to communicate with a pacemaker.

What this could and could not mean for the Guthrie search

The researchers began their work after the Guthrie case generated widespread interest in whether a pacemaker could be used to locate a missing person.

Guthrie was last seen at her Tucson-area home on Jan. 31 and was reported missing the following day. Authorities have treated her disappearance as a kidnapping, and the investigation remains active. No public announcement has confirmed that she has been located. Recent reporting says investigators remain committed to the case.

The new study provides scientific support for one possible search tool, but it does not show that researchers or investigators have detected Guthrie’s pacemaker. Nor does it establish that the technique can produce a location on a map.

Unlike a GPS device, a pacemaker does not continuously transmit its coordinates. A receiving system must be close enough to catch the device’s brief Bluetooth advertisement. Searchers would also need to know, or have an authorized way to determine, which unique identifier belongs to the missing person.

The method would therefore be most useful when investigators have already narrowed the search to a particular building, vehicle, neighborhood or section of terrain. A directional antenna could help indicate where a signal is coming from, while repeated measurements might further reduce the search area.

Important limits outside the laboratory

The study examined only one pacemaker model under controlled, outdoor conditions. The devices were not implanted in people, and human tissue would weaken their signals.

Walls, vehicles, terrain, competing wireless traffic, the position of a person’s body and the orientation of the antenna could also affect detection. A person or vehicle in motion would introduce further challenges.

The researchers detected a signal from an explanted device at 250 meters during one experiment without a tissue model, but they caution that this likely overstates the distance achievable with an implanted pacemaker. They did not determine the technology’s maximum range.

The work concerns detection and identification, not control. The researchers found no evidence through these experiments that the pacemakers could be reprogrammed, disrupted or otherwise altered from a distance.

A potential rescue tool and a privacy warning

The same characteristic that might make a pacemaker useful in a search also raises a difficult privacy question.

Because each device broadcasts a stable identifier, someone who connected that identifier to an individual could potentially recognize the person’s presence or track repeated appearances at different locations. The signal comes directly from the implanted device rather than passing through a hospital’s information systems.

That distinction could leave the data outside some familiar health privacy protections, the researchers warn. Medical-device manufacturers, regulators and policymakers may need to consider safeguards such as changing identifiers, limiting unnecessary broadcasts or designing ways for authorized searchers to identify a device without making patients vulnerable to unwanted surveillance.

The paper captures a tension increasingly common in connected medicine. A wireless signal designed to make health care more convenient could, in an emergency, become an unexpected way to search for someone. The same signal could also expose private information about where a patient goes.

For the search for Nancy Guthrie, the research offers neither a simple answer nor a promise. It provides something more measured: evidence that remote pacemaker detection is technically plausible, along with a clearer picture of what investigators would need to turn that possibility into a practical tool.

The study, “Remote Detection of Cardiac Implantable Electrical Devices,” was published in JAMA Cardiology.