BIOTRONIK Lumax DR ICD Series, Technical Manual, Page: 73 / 176

Lumax Technical Manual 65
2.3.1.2.1 Loss of Capture Detection
In order to ensure against ATM loss of capture detection due to
an isolated non-capture event (i.e. as a result of VES), loss of
capture is only declared if two out of three consecutive cycles
show loss of capture.
2.3.1.2.2 ATM in Lumax HF-T Models
If the device is programmed to biventricular pacing (BiV), the RV
ATM functions in the RV mode as described above. The LV ATM,
if active, is initiated after the RV ATM is complete. For the LV
ATM, the left ventricle is stimulated first with a VV delay of 50 ms
and then completed in a similar manner.
2.4 Intra-Thoracic Impedance
Measurement
Lumax 500/540 Models only
2.4.1 Functional Description
The intra-thoracic impedance measurement of Lumax 500/540 is
based on the painless shock impedance feature of the
Lumax ICD/CRT-D Family. It utilizes 24 measurement windows
evenly distributed over the course of 24 hours to trend the data.
With a total of 1,024 impedance measurements per hour, there is
a significant amount of data being stored in the ICD/CRT-D.
The impedance is measured between RV tip and the distal shock
coil with a programmable excitation current. The device calculates
and stores the mean hourly impedance values and the
corresponding time points. All hourly values obtained within one
Home Monitoring interval are transmitted to the Home Monitoring
service center along with the daily message.
Upon interrogation, the programmer calculates and displays an
intra-thoracic impedance trend of the mean daily impedance
values. This feature is only available after inserting a special code
into the programmer.