BIOTRONIK Lumax DR ICD Series, Technical Manual, Page: 70 / 176

62 Lumax Technical Manual
2.2.8 Additional Sensing Parameters
The parameters of the Additional Sensing Parameters menu are
to provide additional flexibility for physicians to non-invasively
correct over/undersensing situations. The ranges and nominal
values are located in table titled Additional Sensing Parameters in
Section 6 .
Upper Threshold (A, RV & LV) - This feature allows the user to
change the upper sensing threshold level (UT in Figure 4 ) from
the nominal value of 50% of the sensed R-wave / P-wave
amplitude to either 75% or 87.5% of the R-wave / P-wave value.
This feature is used in the ventricle for example to eliminate
oversensing of large T-waves.
Hold of Upper Threshold (RV & LV) - This parameter
determines when the sensing decrement begins after an event
(small step-down on the 50% threshold before LT in the figure
above). This parameter “holds” the threshold at a constant value
(UT in
Figure 4 ) for the programmed time. Maximum Hold Time
is programmable from 10 to 600 ms (T-Wave discrimination
period).
Lower Threshold (A, RV & LV) - This feature allows the user to
change the lower sensing threshold (labeled LT in Figure 4 ) from
the default value of 25% of the sensed R-wave / P-wave
amplitude to either 12.5 or 50% of the measured R-wave/ P-wave
value. This feature is also used in the ventricles to alleviate
T-wave oversensing and/or undersensing of small amplitude
events (e.g., fine VF).
Blank after atrial pacing (RV) - This feature is used to eliminate
sensing of artifacts after atrial paced events. Blank Post atrial
Pace in the RV is programmable from 50 to 100 ms. For the left
ventricle, this parameter is equal to the safety window time
(100 ms).
VES Discrimination after As - This feature is used to correctly
identify and classify ventricular extrasystoles (VES). With each
atrial sensed event (also with Ars falling into PVARP) a special
timing interval is started for the ventricle, if the subsequent
ventricular event does not fall within the AV delay or the
programmed VES discrimination interval, it is classified as a VES.