Radio Interference? FDA Studies Potential RFID Impact On Implantables
Radiofrequency fields are becoming more prevalent in hospitals and other public spaces as a tracking identification tool, but government scientists worry the energy waves could impact the performance of implantable devices such as pacemakers and defibrillators.
Little is know about how radiofrequency identification (RFID) systems may interfere with pacemaker and implantable cardioverter defibrillator (ICD) performance, so FDA researchers, implantable cardiac device makers and RFID system manufacturers have begun to investigate the issue.
Engineers at CDRH's electromagnetic and wireless technology lab at the new White Oak facility in Silver Spring, Md., are testing pacemakers and ICDs from five major cardiac implant manufacturers using seven different RFID readers.
Seth Seidman, an electrical engineer at the agency's Office of Science and Engineering Laboratories (OSEL) who is leading the project, says FDA receives numerous incident reports related to electromagnetic interference from cell phones, anti-theft systems and metal detectors, but the RFID issue is "pretty new."
RFID systems consist of a radiofrequency tag applied to a product or packaging, a reader and data management software. Such systems are increasingly used in hospitals and manufacturing facilities to track supplies and shipments. RFID is also one favored method of tracking individual devices under a unique device identification system that FDA is developing (see chart: "1Will UDI Require RFID?").
"It's going to affect us, it's just not clear exactly how," said Charles Warr, associate director for laboratories at OSEL. "We just wanted to be sure we're up on the technology. ... We'd like to head this off before it becomes a problem."
While FDA has recommendations for pacemaker patients regarding metal detectors and anti-theft systems, "the concern for patients being exposed to RFID systems is potentially greater because these systems can be hidden behind walls and ceilings," Seidman wrote in a 2007 study that detailed the lab team's preliminary findings.
Testing was performed on 18 pacemakers and 19 ICDs from May to September 2006.
FDA, in collaboration with the Advancement of Medical Instrumentation (AAMI) PC69 EMC task force, created an electromagnetic compatibility test method that AAMI refined. The new AAMI/American National Standard was released last November.
"We're trying to figure out the electromagnetic characteristics that are interfering with the pacemakers and ICDs," Seidman said. "They will in turn be used to harden the current EMC standards for pacemakers and ICDs."
Lab Tests ID Effect, Clinical Significance Unclear
The implanted device and lead were immersed in a saline solution that simulated the human body and RFID readers at three common frequencies were lowered toward the device starting from a distance of one meter away.
As the reader approached the device, it interfered with its pacing, sometimes inhibiting pacing or causing inappropriate tachyarrhythmia detection and delivery of therapy and other less significant events, the researchers found.
Seidman said the engineers are now conducting a more rigorous round of testing. With the help of clinicians, they hope to learn more about the clinical significance of the findings.
"Some of it's simple," Seidman said in an interview. "If the pacemaker stops pacing, the clinical significance of that is pretty obvious," but the impact of other reactions is unclear.
According to the published data, at least one reaction was observed in 17 of the 18 pacemakers tested and in 18 of the 19 ICDs tested. FDA says it is also studying the effects of RFID fields on drugs and biologics, in collaboration with the centers for drugs and for biologics.
"It's a potential problem," said AdvaMed VP-Technology and Regulatory Affairs Jeffrey Secunda. "I don't know if there have been situations encountered other than simulations in a laboratory."
"I don't believe the problem itself has been completely characterized at this point."
Lead investigator Seidman says the test method could help pacemaker and ICD manufacturers design products that are less susceptible to RFID interference, and help RFID makers design safer products, too.
"On the medical device side, we're hoping that if [companies] see any problems they'll tell us about them," OSEL's Warr added. "We can do something on the medical device side or the RFID side, or a combination of both."
In addition, by gathering extensive data on the readers, FDA can create simulators to test the impact of RFID fields on other types of devices, Seidman said.
"Neurostimulators [are] on the top of the list of things to do. We'll certainly be looking at other things, especially because of the fact that they'll be going into the hospitals even more."
RFID Is Not The Only Alternative For Tracking
Brad Sokol of Fast Track Technologies, a research consulting firm specializing in RFID and other emerging technologies, agrees that the issue can be resolved through improved product designs, but also suggests that new, upcoming technologies may better resolve the interference problem.
"It depends on the frequency that you're using. It depends on the strength of the signal you're sending out to interrogate the tag," he explained. "There are ways for pacemakers not to be interrupted. However, companies aren't really looking at this yet."
RFID is not the "cure all" for tracking devices in hospitals and patients, Sokol says. Instead, he highlights pipeline products that use MEMS (Micro-Electro-Mechanical Systems), a technology that creates "machines" with dimensions on the micrometer scale.
RFID system makers include Texas Instruments, Philips, Siemens and Germany-based Feig Electronic. A 2005 study forecast that the U.S. market for RFID and related technologies in the hospital and health care sector would grow to $8.8 billion by 2010.
- Jessica Bylander
