BIOTRONIK Evia HF - Automatic Sensor Gain

Chapter 5 Programmable Parameters
Evia HF / HF-T Technical Manual
PAGE 41
exertion is reached during maximum exercise levels. The rate increase, rate decrease and maximum
sensor rate settings must be checked for their suitability with respect to the individual patient before
adjusting the sensor gain.
If the sensor-driven rate is not sufcient at high levels of exertion the sensor gain setting should
be increased. The sensor gain should be reduced if high pacing rates are obtained at low levels
of exertion. Refer to the sensor statistics or perform a sensor optimization if the rate response is
suspected in being inadequate for the patient.
Figure 25: Inuence of Sensor Gain on the Rate Response
5.7.2 Automatic Sensor Gain
Evia CRT-Ps offer an Automatic Sensor Gain setting, which allows the physician to have the Sensor
Gain parameter adjusted automatically.
Figure 26: Automatic Gain Programming
When the Automatic Sensor Gain is activated, the pulse generator samples the sensor-indicated rate.
The sensor gain will be increased by 10%, if the activity rate does not reach or exceed the programmed
activity rate (xed to 90% of maximum sensor rate) for 30 minutes each day over 7 consecutive days.
An increase in gain cannot occur more often than every 7 days. If, during the 24 hour period beginning
at midnight, the activity rate reaches or exceeds the programmed activity rate (90% of maximum sensor
rate) for one hour, the sensor gain setting is reduced by 10%. A change in the sensor gain only occurs
at midnight.
NOTE:
If the reed switch is closed, the accumulated time at maximum sensor rate is reset to zero, and the
sensor indicated rate measurement resumes for the period that remains in that day.
The Automatic Sensor Gain function is primarily inuenced by the Maximum Sensor Rate setting.
Therefore the Maximum Sensor Rate must be appropriately selected.