[The programming of the pulse amplitude: the effect on the longevity of cardiac pacemakers with high and low inhibition currents].
Recently developed rate-responsive cardiac pacemakers are smaller than conventional ones because of their smaller battery capacity. The influence of programming pulse amplitude on battery current was investigated in 13 patients (six women, seven men; mean age 66 +/- 11 years), seven with a small pacemaker (1.2 Ah battery capacity) and six with a conventional model (1.65 Ah battery capacity), 3-12 months after pacemaker implantation. The telemetrically measured battery current of the conventional pacemaker was significantly greater than that of the smaller one. While stimulation currents were the same, the conventional model had a higher inhibition current (22 +/- 0 microA) than the rate-responsive one (7.1 +/- 0.1 microA). At 5 V impulse amplitude the calculated period of functioning was 5.8 years for the conventional pacemaker and 8.2 years for the rate-responsive one. Programming for 2.5 V increased the calculated period of functioning by 1.5 for the conventional and by 5.1 years for the rate-responsive pacemaker. The smaller, rate-responsive pacemaker thus has a longer period of functioning, at least 7 years, because of its superior circuitry. By programming the impulse amplitude at 2.5 V the period is increased to more than 10 years.
Schuchert
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A
Abteilung für Kardiologie, Universitäts-Krankenhaus Eppendorf, Hamburg.
Kuck
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KH
D000368:Aged; D011211:Electric Power Supplies; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000706:statistics & numerical data; D013686:Telemetry; D013997:Time Factors