The latest Guidant pacemaker, the CONTAK RENEWAL 3 RF cardiac resynchronization therapy defibrillator (CRT-D) and ZOOM LATITUDE Programmer use the 914 MHz frequency to communicate. (Previous post here, Guidant press release here.) This spectrum is also used by at least two different products that may be used in hospitals, the Spectralink wireless phone PTB450 and the Plantronics 915 MHz wireless headset. Both of these products use a frequency hopping scheme that could interfere with communications between the Guidant pacemaker and programmer. Rick Hampton, Wireless Communications Manager, Partners HealthCare System, Boston, MA, provided the following information on the Biomed Listserv earlier today:

The FH SpectraLink systems need to be reprogrammed to operate on Frequency Hopping Sequence #3. This particular sequence skips the frequencies utilized by Guidant's devices and is the procedure recommended by SpectraLink in their “Technical Bulletin CS-05-03” which is available here.

Facilities using wireless headsets, such as Plantronics 915 MHz FH units, will need to replace them as there is no mechanism to reprogram their hopping sequence. I'm looking at the Plantronics CS55 and CS55 Micro Headsets, which are both 1.9 GHz DECT systems. More info here.

Some of you may have already been contacted by Guidant to address these issues. Some are likely still on the list to be contacted.

Anyway, if you haven't already heard about this, you should check with your cardiologists and OR staff to see if they are going to be using the new Guidant devices soon and contact your local Guidant reps if they are. Remember to add these devices to your frequency lists maintained for sorting out issues such as this. (You do keep frequency lists, don't you?)

Please note that this potential interference is not a result of errors or omissions by any of the vendors mentioned. Nor should this be interpreted as a risk or weakness inherent in the use of “unlicensed” spectrum, i.e., the Industry Scientific and Medical (ISM) frequency bands. This situation is actually a good example of the kind of testing, collaboration and communications that the FDA and FCC like to see between manufacturers to ensure the proper operation and safety of their products. This is also a good example of why hospitals have created positions like Rick's where RF is actively managed within hospitals.

UPDATE: Rick sent me the following that clarified the interference issues above:

The interference issue isn't really a weakness, just a precautionary measure. I spent a couple of days with their engineering team last summer, touring our facilities with a spec analyzer and seeing what the various other communications systems did to their link. It slowed things down some, but the communications still got through. Guidant's major concern was the physicians complaining about the system responding slowly. All the “old” programming methods are still available, but it turns out that not having the programming wand in the sterile field is one heck of an incentive to use this system.

UPDATE: Another reader asks how great a slow-down the wireless connection will experience in the presence of other devices using the same frequency. The answer depends on the degree of data loss resulting from interference, so resulting speed reductions will vary greatly – from barely noticeable to delays rendering the wireless data link impractical. The traditional programming wand is not impacted – it uses induction to establish the communications link rather than a wireless data link.

[Hat tip: Biomed Listserv]