User Manual

168 Lumax Technical Manual
5.2 Longevity
The service time of an ICD/CRT-D can vary based on several
factors, including the number of charge sequences, programmed
parameters, number of tachyarrhythmias detected, relative
amount of bradycardia pacing required, pacing lead impedance,
storage time, battery properties, and circuit operating
characteristics. Service time is the time from beginning of service
(BOS) to the elective replacement indication (ERI). To assist the
physician in determining the optimum time for ICD/CRT-D
replacement, a replacement indicator is provided that notifies the
user that replacement within a certain period of time is required.
Upon reaching ERI, the battery has at least enough energy left to
continue monitoring for three months along with the ability to
deliver six high-energy shocks. After this period, all
tachyarrhythmia detection and tachyarrhythmia therapy is
disabled.
CAUTION
Charge Time - When preparing a high energy shock the
charge circuit stops charging the capacitors after 20 seconds,
and delivers the stored energy as shock therapy. After the
device reaches ERI the stored energy may be less than the
maximum programmable energy for each shock.
The projected service times from beginning of service (BOS) to
elective replacement indication (ERI) are listed in the following
tables. All estimates were calculated assuming a pacing rate of
60 ppm with a pulse width of 0.4 ms and pulse amplitude of 2.8
volts and 500 ohm pacing impedance with all shocks at maximum
programmable energy at 37C. It is assumed that the shocks are
equally spaced throughout the life of the ICD/CRT-D. The
estimates associated with 0% pacing support assume the
ICD/CRT-D is sensing an intrinsic sinus rhythm at a rate of
70 bpm. The tables represent the mean longevity estimates for
the specified devices. If there are multiple available batteries for a
particular device, the worst case longevity option is presented.