User Manual

Lumax Technical Manual 117
2.9.11.1 Sensor Gain and Threshold
The Sensor Gain defines how much the sensor signal is amplified
before it is transformed to a rate change. When the Sensor Gain
is low (e.g., 2), a great deal of exertion is needed to cause a
significant change in sensor output (and an equal change in the
pacing rate). When the Sensor Gain is high (e.g., 18), little
exertion is needed to increase the sensor output. Ideally, the gain
is programmed so the maximum desired pacing rate during
exercise occurs at a maximum exertion level. The Lumax 600/640
& 700/740 models use AUTO, VERY LOW, LOW, MEDIUM,
HIGH, and VERY HIGH values to program the Sensor Gain.
The device ignores all activity that occurs below the Sensor
Threshold because the Sensor Threshold defines the lowest
sensor output that initiates a change in the pacing rate. Five
different threshold settings are available including; VERY LOW,
LOW, MEAN, HIGH, and VERY HIGH. When the threshold is
programmed optimally, the basic rate is the effective rate while
the patient is not moving (at rest).
2.9.11.2 Rate Increase/Decrease
The Rate Increase and Decrease parameters work with
the
Sensor Gain to determine how quickly the pacing rate will
increase or decrease during changes in the sensor output.
2.9.11.3 Maximum Sensor Rate
Regardless of the sensor output, the sensor-driven
pacing rate
never exceeds the programmable Max. Sensor Rate. The
maximum sensor rate only limits the pacing rate during sensor-
driven pacing.
2.9.11.4 Auto Sensor Gain
The
Lumax ICDs/CRT-Ds offer Automatic Sensor Gain Auto
Gain settings, which allows the Auto Gain parameter to be
adjusted automatically.
When the Automatic Sensor Gain is activated, the pulse
generator samples the sensor-indicated rate.
 If 90% of the maximum sensor rate is not reached for the
duration of 1 hour within a week (7 days), gain is
incremented by one step.