BIOTRONIK Cardiac Airbag, Technical Manual, Page: 30 / 92

24 Cardiac Airbag Technical Manual
ic Sensitivity Control with Standard Figure 1. Automat
Setting
Figure 1 provides a trol
with the sensitivity programmed to Standard. The tracked R –
ave is measured to be 6.0 mV following the sensed refractory
Y
- The Enhanced VF Sensitivity
nts ensure that the threshold reaches the lower
values more quickly in order to ensure that all VF signals are
sensed appropriately.
n illustration of Automatic Sensitivity Con
w
period the UT is set to 3.0 mV. After the T-wave discrimination
period, the threshold is further reduced to 1.5 mV. Both the
Upper and Lower Thresholds decay over time, but the Minimum
Threshold is never violated. Nominally, the minimum threshold
is set to 0.8 mV, but it can be adjusted by the user.
E
N H AN C E D
VF S
E N S I T I V I T
setting is specifically designed to improve VF detection when the
VF signal is very small. Two adjustments are made to ASC with
this setting:
•
The T-wave discrimination period is decreased to
100 ms, thus eliminating the UT
•
The decay rate of the LT is increased to 0.125 mV every
250 ms.
These adjustme