BIOTRONIK Evia DR, Technical Manual

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58 Evia Technical Manual
7.2.2 Rate Hysteresis
Hysteresis can be programmed OFF or to values as low as
-5 bpm and as high as -90 bpm. The Hysteresis rate is based on
the lower rate and the value of the programmable parameter.
Hysteresis is initiated by a sensed event. The resulting
Hysteresis rate is always less than the lower rate. A conflict
symbol will appear and transmission will be prohibited for
Hysteresis rates which are less than 30 bpm. The ability to
decrease the effective lower rate through Hysteresis is intended
to preserve a spontaneous rhythm. The pulse generator
operates by waiting for a sensed event throughout the effective
lower rate interval (Hysteresis interval). If no sensed event
occurs, a pacing pulse is emitted following the Hysteresis
interval.
N
OTE
:
If rate adaptation is active, the Hysteresis rate is based on
the current sensor-indicated rate and the value of the
programmable parameter.
Hysteresis is not available in CLS or DVI, and DVIR modes.
If Hysteresis is used in the DDI mode, the AV delay must be
programmed shorter than the spontaneous AV conduction
time. Otherwise, stimulation in the absence of spontaneous
activity occurs at the hysteresis rate instead of the lower
rate.
During night mode the rate will not fall below the
programmed night rate even if Hysteresis can take it to a
lower rate. Programming conflicts arise when the total
decrease in rate is below 30 ppm. Care should be exercised
to avoid programming a Night Mode rate and hysteresis that
is below what is appropriate and may be tolerated by the
individual patient.