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Chapter 5 Programmable Parameters
Evia HF / HF-T Technical Manual
PAGE 40
the stimulation rate. Sensing and inhibition remains in effect during sensor controlled operation. In
the case of high pacing rates, however, the refractory periods may cover a majority of the lower rate
interval, resulting in asynchronous operation.
When in CLS mode, the pulse generator monitors and processes the intracardiac impedance signal
associated with myocardial contraction dynamics. Changes in the waveform of this impedance signal
are associated with changes in the contraction dynamics of the patient’s heart due to the heart’s
inotropic response to exercise. By monitoring these changes, the pulse generator can provide a pacing
rate that is appropriate and specific to the patient’s physiologic demands.
For a complete list of rate-adaptive pacing modes available in the Evia CRT-P, see Section 13.1.
The following functions are available for tailoring the motion based rate adaptation to the individual
patient except for the maximum closed loop rate, which is relevant to CLS.
Table 10 shows a summary of the parameters associated with rate adaptive pacing.
Parameter Name Range
Standard
Values
Unit
Maximum Activity
(Sensor) Rate
80...(5)...180 120 bpm
Sensor Gain
1.0, 1.1, 1.3, 1.4, 1.6, 1.8,
2, 2.3, 2.6, 3.0, 3.3, 3.7,
4, 4.5, 5, 6, 7, 8, 8.5, 10,
11, 13, 14, 16, 18, 20, 23
4 none
Automatic Gain OFF, ON OFF none
Sensor Threshold
very low, low, medium,
high, very high
medium none
Rate Fading OFF, ON OFF none
Rate Increase 1...(1)...10 4 bpm/cycle
Rate Decrease 0.1, 0.2, 0.5, 1.0 0.5 bpm/cycle
Table 10: Rate Adaptive Pacing Parameters
5.7.1 Sensor Gain
Figure 24: Gain Setting Choices
The sensor gain defines the slope of the linear function between exertion and pacing rate. It designates
a factor by which the electric signal of the sensor is amplified prior to the signal processing stages.
The programmable amplification permits adaptation of the individually programmed sensor gain to the
desired rate response. The optimum setting is achieved when the desired maximum pacing rate during