User's Manual

Table Of Contents
Table 8. Lead measurements (continued)
Pace/ sense lead
(acute)
Pace/ sense lead
(chronic)
Shocking lead (acute
and chronic)
Lead impedance (at
5.0 V and 0.5 ms left
ventricle)
> programmed Low
Impedance Limit
(200–500 )
< programmed High
Impedance Limit
(2000–3000 )
> programmed Low
Impedance Limit
(200–500 )
< programmed High
Impedance Limit
(2000–3000 )
a. Amplitudes less than 2 mV cause inaccurate rate counting in the chronic state, and result in inability to sense a
tachyarrhythmia or the misinterpretation of a normal rhythm as abnormal.
b. Lower R-wave amplitudes and longer duration may be associated with placement in ischemic or scarred tissues. Since signal
quality may deteriorate chronically, efforts should be made to meet the above criteria by repositioning the leads to obtain
signals with the largest possible amplitude and shortest duration.
c. Durations longer than 135 ms (the pulse generator’s refractory period) may result in inaccurate cardiac rate determination,
inability to sense a tachyarrhythmia, or in the misinterpretation of a normal rhythm as abnormal.
d. This measurement is not inclusive of current of injury.
e. Changes in the debrillation electrode surface area, such as changing from a triad conguration to a single coil conguration,
can affect the impedance measurements. Baseline debrillation impedance measurements should fall within the
recommended values indicated in the table.
Step E: Form the Implantation Pocket
Using standard operating procedures to prepare an implantation pocket, choose the position of the pocket
based on the implanted lead conguration and the patient’s body habitus. Giving consideration t o patient
anatomy and pulse generator size and motion, gently coil any excess lead and place adjacent to the pulse
generator. It is important to place the lead into the pocket in a manner that minimizes lead tension, twisting,
sharp angles, and/or pressure. Pulse generators are typically implanted subcutaneously in order to minimize
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