Cardiac stimulator 4427 Easypace - Instructions for use
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be observed to verify normal operation. If abnormal performance is observed, additional measures may
be necessary, such as re-orienting or relocating the 4427 device.
(e) Over the frequency range 150 kHz to 80 MHz, field strength should be less than 10 V/m.
(1) WARNING!
An electro-magnetic interference shielding system is embedded in the device in order to detect noise
signals with frequencies above 300 ppm: during VVI stimulation and with such interferences, the unit will
be set to V00 mode while the User is notified by means of an “EMI” warning on the display; the devices
switches to the VVI mode again once the interference is over (see § 11.4).
Besides that an electro-magnetic field, with frequency within the range (80 - 1000 MHz) and rate below
300 ppm, with an high sensitivity set on the device, could override the protection system: in that case the
device won’t switch to V00 mode causing random loss of the pacing pulse, for no longer than 2 pacing
periods; the complete functionality is regained when the interference is over. The afore mentioned event
can be considered extremely rare. In case of a VVI mode use it’s recommended to check that in the
environment where the device will be used there are no interferences like the one just described,
especially if the Patient is not constantly monitored. If not it’s advisable to find and possibly remove the
source of the interference before proceeding. If the removal of the source is not feasible it’s
recommended to pace in V00 mode.
A method of spotting the presence of the interferences is based on a pre-procedure check: before the
procedure set the device to sensing mode, preferably connecting it to a 500 Ω load. If such
electromagnetic fields are present in the environment, the ECG will detect an activity similar to the
spontaneous one and will show the correspondent ppm.
Recommended separation distances between 4427 device and portable and mobile
RF communication equipment
The 4427 Easypace is intended for use in an electromagnetic environment in which
radiated RF disturbances are controlled. The User of the 4427 device can help prevent
electromagnetic interference by maintaining a minimum distance between portable and
mobile RF communication equipment (transmitters) and the 4427 device, as
recommended below, according to the maximum output power of the communications
equipment.
Separation distance according to frequency of transmitter (m)
Rated maximum output power
of transmitter (W)
80 MHz to 800 MHz
Pd 2,1=
800 MHz to 2.5 GHz
Pd 3,2=
0,01 0,12 0,23
0,1 0,38 0,73
1 1,2 2,3
10 3,79 7,27
100 12 23
NOTE:
• At 80 MHz and 800 MHz the separation distance for the higher frequency range applies.
• These guidelines may not apply in all situations. Electromagnetic propagation is affected by absorption
and reflection from structures, objects and people.
Data reported in this chapter are valid for the device used in the manner and with
accessories stated in this instructions for use. The use of accessories other than those
specified may result in increased emissions or decreased immunity.
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