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Edition No. 7/E April 1998
Interference of pacemakers by mobile phones

Prof. Dr.-Ing. W. Irnich, Dr. rer. nat. L. Batz, T.A. R. Müller, Dipl.-Ing. R. Tobisch Institut für Medizinische Technik der Justus-Liebig-Universität Gießen

The topic “interference of pacemakers by mobile phones” has found a surprisingly strong interest not only in pacemaker patients but also in the public opinion and in field producers responsible for mobile phones. Though there have been already three reports on this topic, further investigation are carried out to get additional data. This is the more surprising as the problem of interference in the past has scarcely found the attention which it deserves in the interest of the patient.

The quality of interference detection in today’s pacemakers has not really been improved since the seventeeth, however the quality of interference suppression has largely increased due to encapsulation of pacemakers by metallic housings. However, interference immunity against highest frequencies, as they are produced by mobile phones of the C-, D-, and E-net, is surely not taken into design considerations.

It was the intention of our investigation to test as many pacemaker models as possible with the aid of an invitro measuring setup, whether incompatibility with phones of the C-, D-, and E-net may happen. We had resources to 231 different models of 20 manufacturers. During the measurements a pulse generator together with a suited lead was situated in a 0.9g/l saline solution and the antenna of a mobile phone was positioned as close as possible. If the pulse generator was interfered, the antenna was elevated until interference ceased. As “maximum interference distance” the gap was defined up to which interference hapened. All three nets were tested one after the other.

Out of 231 pulse generator models 106 pieces correspending to 45.9% were interfered either by C- or D-net, if both are summed up. However, this view is too pessimistic as no patient will simultaneously use C- and D-net phones. Separated into C- or D-net interference the result is 30.7% or 34.2% respectively of all models tested. The susceptible models on their part represent 18.6% or 27% respectively of today’s living patients. All models were resistant against the E-net.

With respect to D-net-phones, all pacemakers of six manufacturers proved to be unaffected. Eleven other manufacturers possesed affected and unaffected models as well.

The following advices for patients and physicians can be derived from our investigations: Though 27 % of all patients may have serious problems with D-net phones (not C- or E-net), the usage should not be questionned generally . On the contrary, patients with susceptible devices should be adviced that a distance of 25 cm is sufficient to guarantee integrity of the pacemaker with respect to handies. Portables, on the other hand should have a distance of about half a meter. It would be desirable for the future if implanting physicians would only use pacemakers whose immunity against mobile phones would be testified by the manufacturers.

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