User Manual

Table Of Contents
Lumax Technical Manual 121
2.10.2 Pacing Impedance Measurements
The Lumax ICDs/CRT-Ds have the ability to perform automatic
and manual pacing impedance measurements. The devices can
measure the pace impedance in all leads; RA, RV and LV. In
Lumax 300/340 and 500/540 models, the measurement can be
performed in any the of the pacing configurations; RA, RV, LV or
BiV. In Lumax 600/640 and 700/740 models, it uses a sub-
threshold measurement in all channels connected to leads
automatically. In all Lumax devices, the LV pacing polarity is also
programmable for impedance measurements additionally. (See
Section
2.1).
The impedance in Lumax 300/340 and 500/540 models is
measured using a triggered mode with paces of 2.4 Volts and
0.5 ms, or programmed value (whichever is higher). During
automatic measurements both atrial (only with an atrial pacing
mode) and ventricular (RV, LV or BiV) impedances are
measured. However, they will not be measured if the normal
pacing output is programmed to a value greater than the
impedance test output (2.8 V).
2.10.3 Shock Impedance Measurements
The Lumax ICDs/CRT-Ds have the ability to perform automatic
and manual painless shock impedance measurements. The
devices can measure the shock impedance by delivering an
undetectable 3 nJ shock by applying 1 mA of current. The device
then measures the resulting voltage drop and calculates the
resulting shock impedance. This impedance measurement is tied
to the pacing impedance measurement, meaning that the pacing
impedance measurement is done daily, and shock impedance is
done (concurrently with pacing impedance measurement) every
fourth day. The results of these impedance measurements are
available through the device’s statistics function.