Specifications

7 x 9 inches (178 mm x 229 mm)
Medtronic Confidential
Refer to the “Reference man.” category in doc#163256 for Printing
Instructions.
196407001 Rev A
[MANUAL THRESHOLD
]
— Select this test to manually select and test specific
values for amplitude and pulse width. Automatic value reduction is not used
in this test. Only the selected values are tested while you press and hold the
[
PROGRAM
] button.
[
INHIBIT PACING
]
—
This button is available on the Threshold Test Start
screen as a convenience option. You can use it to temporarily inhibit output
of the pacemaker to view the patient’s underlying rhythm or determine the
intrinsic rate. Use of this feature is described on page 5-9.
Before You Begin the Test Procedure
Precautions
At any point during a threshold test, lifting the programming head from
over the pacemaker for at least 2 seconds will return the pacemaker to its
permanently programmed state. This action should be taken in the event of
a programmer malfunction, loss of power, or absence of an appropriate
command confirmation.
Be aware that movement of the programming head during an automatic
threshold test may interrupt communication between the programmer and
pacemaker, which will terminate the test.
A Note About Hysteresis
If Hysteresis has been programmed to ON during previous use of the AAI,
AAT, VVI, or VVT pacing mode, it will be in effect when ever you return
to one of these modes — even temporarily such as during a threshold test.
If a message indicates that Hysteresis is in effect, you can program it to
OFF by returning to the Pacing Parameters screen. To access Hysteresis,
you must select one of the single chamber modes mentioned above.
Waveform Display
During setup and execution of a threshold test, the screen continuously
displays the patient’s ECG and the telemetered waveforms being received
from the pacemaker. Adjust the ECG trace so that you easily can see pacing
artifacts and the resulting depolarization wave. During a threshold test, you
must be able to determine whether or not capture is maintained or lost as
pacemaker output is reduced, either manually or automatically.
Refer to Chapter 5, pages 5-6 to 5-8 for information about using and
adjusting the waveform display and about Marker telemetry.
Selecting Pulses Per Decrement
During a threshold test (except “Manual Threshold”), the programmer
controls the number of pacing cycles it allows to occur at each threshold
7-4 Using the Programmer