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Biomedical subjects

H J Bisping

Publications and source records attributed to H J Bisping.

6 recordsLinked to original sources

Electromagnetic interference in implantable pacemakers.

The inhibited pacemaker (VVI or AAI) has become the most popular in recent years because of its ability to combine a physiological advantage with economical current consumption in cases with spontaneous activity. One of its disadvantages is its sensitivity to external electromagnetic interference. Though today's pacemakers possess effective protection against most interference signals there may be instances in which patients are subjected to uncomfortable or even life-threatening situations. This is the case of "amplitude modulated" or "pulsed" fields with modulation frequencies in the physiological range. Fields of that sort have been found in the vicinity of a welder, an electric steel plant, and in medical practice where therapeutic currents were applied. Even touch-actuated switches may influence a demand pacemaker. However, these situations may be overcome by a device within the pacemaker for simple time analysis which can be carried out with few components. If electromagnetic fields of diathermy equipment are applied, today's pacemakers may react with intolerably high or low rates. They should, therefore, be avoided.

Electromagnetic Phenomena

[Radiation therapy in patients with electronic cardiac pacemakers: interferences with the pacemaker's function by ionizing radiation and other sources of disturbances (author's transl)].

In the course of radiation therapy and connected diagnostical measures ionizing radiation and other sources of disturbance may interfere with the function of permanent pacemakers. The conditions of such hazards are investigated in theory and practice making allowance for the different susceptibility to trouble of various models of permanent pacemakers. It appears that no extension of long-term follow-up of the cardiac pacemaker's function is needed with regard to possible late effects of ionizing radiation, but that the follow-up of pacemaker-patients during their first period of treatment should not be neglected, since other sources of electronic interference may be present. Routine checks as radiotherapy installations should also include possible sources of disturbance to electronic pacemakers.

Aged

[First clinical experiences with a new transvenous endocardial screw-in lead (author's transl)].

From November 1976 to January 1977 a total of 10 patients were served with a new transvenous endocardial screw-in lead. In every 5 cases the lead was anchored in the right atrium respectively in the right ventricle. The lead presented itself by good biomechanical (flexibility, tension resistance) and bioelectrical properties. Because of its constructural features it was to insert easily and without any complication. Moreover, it could be placed anatomically stable by choice either in the right atrium or ventricle.

Aged

[Influence of radio and television sets on implanted cardiac pacemakers (author's transl)].

Investigations done on implanted pacemakers with a low threshold against extraneous signals and in-vitro tests under suitable conditions both showed that pacemaker wearers may go near television and accessories such as ultrsound distant control or flexless infrared ear phones without any danger. Radio and television sets are fitted to an increasing degree with electronic sensor switches which initiate various functions after a slight touch. This satisfies present regulations of German Electrical Engineers concerning permitted contact currents. However, pacemaker patients can cause impulse defects by use of sensor switches provided the contact current is less than 25 muA. Sensor technique will in the future be introduced for everyday use on a large scale. Therefore, pacemaker patients should be alerted to the possibilities of an influence, and industry should be made to reduce contact currents in sensors to values below 20 muA.

Infrared Rays