How smartwatches and fitness trackers can interfere with pacemakers

Researchers examined the operation of CRT devices from three major manufacturers while applying the electrical current used in bioimpedance sensing.

Bioimpedance sensing is a technology that emits a small, imperceptible electrical current (measured in microamps) into the body.

Electric current flows through the body, with sensors measuring the response to determine the person’s body composition (i.e. skeletal muscle mass or fat mass), stress level or vital signs, such than the respiratory rate.

Bioimpedance sensing generated electrical interference that exceeded accepted Food and Drug Administration guidelines and interfered with the proper functioning of CIED, said Benjamin Sanchez Terrones, assistant professor in the Department of Electrical and Computer Engineering at the University of Utah and principal investigator of the study. , in a report.

Sanchez Terrones stressed that the results, determined by careful simulations and bench tests, do not pose an immediate or clear risk to people who wear the trackers.

However, he said the different levels emitted could lead to unnecessary pacing interruptions or shocks to the heart.

Our findings call for future clinical studies examining patients with CIED and wearables, Sanchez Terrones said.

The interaction between home appliances and, more recently, smartphones, with CIEDs has been studied in recent years.

Almost all implantable heart devices already warn wearers about potential interference from various electronic devices due to magnetic fields, for example, carrying a cell phone in the breast pocket near a pacemaker.

The researchers said the rise of wearable health technologies has grown rapidly in recent years, blurring the line between medical devices and consumer devices. Until this study, researchers said objective evaluation to ensure safety has not kept pace with new gadgets.

Our research is the first to investigate devices that use bioimpedance sensing technology and uncover potential interference issues with CIEDs such as CRT devices, said Sanchez Terrones. We need to test on a larger cohort of devices and in patients fitted with these devices. A collaborative investigation between researchers and industry would be helpful to ensure patient safety.

Dr. John Higgins, professor of cardiovascular medicine at McGovern Medical School at UTHealth Houston, said Healthline experts had wondered about possible conflicts between indoor and outdoor devices. since 2007.

Smartwatches, smart scales, smart rings and other smart/wearable devices are known to often have small magnets inside, for example Neodymium-Iron-Boron (NdFeB) magnets, which are small size but produce strong magnetic fields, Higgins said. Which can interfere with the operation of permanent pacemakers (PPM) and implantable cardioverter defibrillators (AICDS) due to electrical interference. Usually the laptop needs to be close enough (less than) two to three inches to create major issues.

Higgins said possible complications include the activation (triggering) or deactivation of the implanted heart defibrillator and the permanent pacemaker changing modes (so the pacemaker may not function normally).

I haven’t had any cases myself, but [Ive] heard of some AICD/PPM malfunction issues, Higgins noted. Physicians electrophysiologists (those who insert AICDs and PPMs) usually warn patients.

Dr. Jim Liu, a cardiologist at Wexner Medical Center at Ohio State University, told Healthline he hasn’t come across any cases of smartwatches or other wearable technology interfering with internal medical devices.

He also hasn’t heard of doctors discussing a potential problem.

I don’t believe physicians are currently warning patients about wearable devices and interference with CIEDs, Liu said. As the study mentions, previous studies have shown no problems with bioimpedance devices and CIEDs.

Liu said it’s important to remember that the study is based on a simulated model and an electrical circuit.

It’s unclear whether these findings translate to an actual human body, Liu said. Further research would be needed before knowing if this is really a real problem.

Nancy Mitchell is a registered nurse and medical writer and has managed care units for people with cardiovascular disease.

She told Healthline that with people becoming more involved in their own healthcare and wearable devices becoming more powerful, she could see a time when there could be issues.

According to the findings, pacemakers and smart devices work by emitting electrical charges, Mitchell said. Smartwatches could potentially exceed the FDA-approved threshold for these voltages, which, in turn, could adversely affect the performance of pacemaker implants. In some cases, the increased tension can manifest as shocks for patients. This alone could increase their anxieties, especially if they are unaware of the real cause of those occasional zaps.

Mitchell said the risk would likely vary depending on the user.

It’s hard to single out a particular brand or device, Mitchell said. The charges emitted strongly depend on the biometrics of the individuals. Thus, a device may cause complications for some patients and nothing significant for others.

Higgins said he doesn’t recommend people with internal devices use external health monitors.

We advise against the use of these devices with bioimpedance technology in this population (PPM or AICD) due to potential electrical interference, she said. Patients should be informed of this risk and advised to keep wristbands/other wearables/other devices at least 6 inches from their heart devices, and should not wear them to sleep.

Higgins said the issue will likely need to be resolved at some point.

Alternative technology to a magnet/magnetic field in these wearable devices may need to be developed, or a stronger barrier/force field in the AICD/PPM shield to block this interference may need to be developed, he said.