[Body movement as pacemaker induction value: comparison of 2 activity-triggered pacemakers].

This article compares the rate behavior of the activity-triggered pacemakers, the Activitrax (A) and the Sensolog (S), during bench tests as well as in patients under defined ergometric conditions and during every day life with special reference to the susceptibility of both systems to external noise. In the bench tests both pacemakers were mounted on a swingbord and subjected to controlled vibrational force. In the first experiment the frequency, in the second experiment the energy was varied. In two groups, one with S, one with A implanted, each consisting of 10 patients, the discriminating power of workload changes was examined under defined treadmill exercise. Furthermore in 5 patients of each group the rate behavior of S and A under daily life conditions and during common environmental noise was registered using Holter-ECG. In the bench tests S and A displayed a frequency-selective mode of operation between 2 Hz and 70 Hz with the highest sensitivity (resonance frequency) at 10 Hz. In patients, S showed a significantly higher discriminating power to changes of workload under treadmill exercise. According to y = 0.27x + 85.8 (r = 0.92) the relationship between the pacing rate of S and the power was linear whereas with y = 0.04x + 89.8 (r = 0.2) the pacing rate of A was almost independent of the given power. The susceptibility to external noise occurring during riding a car, streetcar or train with rate increases between 7 ppm and 12 ppm did not significantly differ in both systems.(ABSTRACT TRUNCATED AT 250 WORDS)