BIOTRONIK Evia HF, Technical Manual, Page: 119 / 138

Chapter 11 Elective Replacement Indication (ERI)
Evia HF / HF-T Technical Manual
PAGE 111
11. Elective Replacement Indication (ERI)
The service time of Evia CRT-Ps vary based on several factors, including battery properties, storage
time, lead system impedance, programmed parameters, amount of pacing and sensing required,
and circuit operating characteristics. Service time is the time from beginning of service (BOS) to the
end of service (EOS). To assist the physician in determining the optimum time for pulse generator
replacement, an elective replacement indicator is provided that is activated when the battery cell
capacity drops to a predetermined level. The following table defines the different service cycles (at
standard settings, 37°C, and with a lead impedance of 500 ohms). The beginning of the replacement
cycle is displayed on the programmer after pulse generator interrogation and appears on the printout.
Table 21 shows the service cycle definitions.
Abbreviation Service Cycle Definition
BOS Beginning of Service Normal service cycle; battery in good condition
ERI
Elective
Replacement
Indication
Identifies the time of elective replacement indication.
The rate occurring at ERI depends upon the
programmed mode and magnet application.
EOS End of Service
Identifies the end of the elective replacement
indication period.
Table 21: Service Cycle Definitions
The pulse generator indicates the need for replacement by a defined decrease in the programmed rate
without a magnet applied. The rate change is dependent on the programmed pacing mode.
The pacing rate decreases by 11% when programmed to DDD(R), DDT(R), D00(R), VDD(R), VDI(R),
VDT(R), VVI(R), VVT(R), AAI(R), AAT(R), or A00(R).
In DDI(R) and DVI(R) modes, only the V-A delay is extended by 11%. This reduces the pacing rate by
4.5-11%, depending on the programmed AV delay.
The pulse generator indicates the need for replacement by a defined decrease of its rate after magnet
application and the programmer displays it upon interrogation of the pulse generator programmed
parameters. The magnet rate in all modes decreases as shown in Table 22 .
Magnet Mode
Cycles 1-10 after
magnet application
After Cycle 10
Automatic
Asynchronous, basic
rate at 80 ppm
Synchronized with basic
rate reduced by 4.5-11%
Asynchronous
Asynchronous, basic
rate at 80 ppm
Asynchronous with basic
rate at 80
Synchronous
Synchronized with basic
rate reduced by 4.5-11%
Synchronized with basic
rate reduced by 4.5-11%
Table 22: Pulse Generator Behavior after Reaching ERI
If the pulse generator is programmed to dual chamber pacing, it will switch to single chamber
pacing when it reaches the elective replacement indication. The “ERI mode” varies according to the
programmed pacing mode and is indicated by the pulse generator.