BIOTRONIK Evia DR, Technical Manual

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Evia Technical Manual 143
12.7.2 Adjusting the Sensor Gain
The sensor gain controls the change in stimulation rate for a
certain change in workload detected by the sensor. An exercise
test is recommended in order to achieve a rate response
proportional to work load by optimizing the sensor gain. If the
pacing rate tends to be too high for the specific amount of work
load or if the selected maximum sensor rate is achieved at too
low of an exercise level, the sensor gain should be reduced by
selecting a lower gain setting. If, on the other hand, rate
adaptation is insufficient for a specific amount of workload,
selection of a higher gain setting may be indicated. The memory
functions can be used to record the pacing rate during exercise.
The sensor rate forecast function facilitates optimization of the
rate-adaptive parameters.
12.7.3 Adjusting the Sensor Threshold
The sensor threshold controls the (motion) signal level that has
to be exceeded to cause a rate increase. This parameter is
meant to assure a stable pacing rate at rest and to prevent rate
increases at signal levels not consistent with physical exertion.
The sensor gain should be optimized prior to adjusting the
sensor threshold. Otherwise, changing of the gain setting will
cause changes in the effective threshold.
If rate increase is caused by low level activities, when no
rate-adaption is desired, the sensor threshold setting should be
increased by selecting the next higher setting (e.g., low to
mean). If, on the other hand, the pulse generator tends to
respond only at higher levels of work, a reduction of the sensor
threshold may be indicated (e.g., high reduced to mean). It may
be useful to record a sensor test trend for evaluation of sensor
response. The sensor rate forecast may also be used to tailor
the sensor threshold to the patient.