The project contractor, 7 layers AG, has carried out comprehensive measurements and analyses of the resistance to interference of currently available standard implanted cardiac pacemakers and implantable cardioverter defibrillators (ICD) on behalf of the German Federal Institute for Occupational Safety and Health (BAuA). The results of measurements taken on more than 75 pacemakers and over 10 ICD types were integrated in a database entitled "Interference Resistance". This database is used by the BAuA as an elementary basis for assessing the risk to persons with such implants who are exposed to electric and magnetic fields in the low-frequency range at work.

Following an introduction into the basics of pacemaker and ICD technology, as well as the possible malfunctions caused by the guided input of interference signals, the current situation with regard to the standardisation of pacemakers and ICDs was examined. The loopholes in the test processes prescribed by the outdated pacemaker and ICD standards were closed by proposals which were integrated in computer-assisted assessment and measuring procedures. These are also suitable for pacemakers and ICDs. The results of the analyses are listed in the form of type-related statistics. The aim was to determine the frequency-related interference threshold of the individual pacemaker and ICD types, below which the implants are not adversely affected. Besides this, the extent to which the interference threshold is affected by other parameters, such as the detection threshold set on the implant, the configuration of the electrodes and special forms of interference signals such as beatings (frequency fluctuations) and pulse-modulated signals with different switching-in and switching-off phases was also examined.