METRON QA-45, User & Service Manual, Page: 39 / 74

b. The following menu will be displayed:
c. Select the desired waveform by pressing UP (F2) or
DOWN (F3) and then Select (F4) . Press CANCEL (F5) to
cancel the selection. After selection the main menu will
reappear.
d. Select SENS. TEST (F2) . The following display will ap-
pear:
e. Upon completion of testing the results will be displayed un-
der RESULT. Press SENS. TEST. CANCEL (F5) to can-
cel the test.
5.4 Refractory Period Test
1. General. This test is used to test the time interval in millisec-
onds (ms) during which the pacemaker is insensitive to any ex-
ternal inputs. QA-45 does this by measuring the maximum time
interval after the generation of a pacer pulse, and maximum
time interval after a QRS wave.
a. Refractory Period . A time interval in milliseconds, during
which a pacemaker is insensitive to any external inputs. If a
QRS is detected during this period, the pacemaker ignores
it. On the other hand, if a QRS is detected outside the re-
fractory interval, then the pacemaker resets its internal
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