21
Figure 8.
PSA clips attached to Connector Tool
2.
Perform the measurements as indicated in the table.
Table 3.
Recommended threshold and sensing measurements
Signal Type
Amplitude
Duration
Pacing
Threshold
Impedance
Pacing/
Sensing
≥ 5 mV
< 100 ms
≤ 1.5 V
300–1200 Ω
Defibrillation
≥ 1 mV
< 150 ms
NA
20–125 Ω
a.
Pulse width setting 0.5 ms.
•
Pulse generator measurements may not exactly correlate to the PSA
measurements due to signal filtering. Baseline measurements should
fall within the recommended values indicated in the table.
•
Lower intrinsic potentials, longer durations, and higher pacing
threshold may indicate lead placement in ischemic or scarred tissue.
Because signal quality may deteriorate, reposition the lead if
necessary to obtain a signal with the largest possible amplitude,
shortest duration, and lowest pacing threshold.
•
Changes in the defibrillation electrode surface area, such as changing
from a TRIAD configuration to a single coil configuration, can affect
the impedance measurements. Baseline defibrillation impedance
measurements should fall within the recommended values indicated
in the table.
CAUTION:
R-wave amplitudes of less than the recommended value
can cause inaccurate rate counting in the chronic state, possibly
resulting in failure to sense a tachyarrhythmia or misdiagnosis of a
normal rhythm as abnormal. Signal durations that exceed the
programmed refractory period of the pulse generator can cause
inaccurate rate sensing which may cause inappropriate behavior.
3.
If measurements do not conform to the values in the table, perform the
following steps:
•
Remove the PSA alligator clips from the Connector Tool.
