Biomedical Engineering Reference
In-Depth Information
the manufacturer and type of device, serial number, and
configuration of lead connections are stated on the device
case. In addition, the wand that serves as the connection for
the implantable leads coming from the heart is positioned
here. Conductors from the input and output elements and
leads are led to the header, where they are fixed by setscrews.
Every pacing or shock electrode has a contact to which it is
fixed by a setscrew or spring. To ensure the device is water-
proof, the setscrews are covered by a seal plug. To tighten the
setscrews, a bidirectional torque wrench (screwdriver) is
used. A correct pressing force of the setscrew on the electrode
and protection against damaging by overtightening is ensured
by the torque wrench calibration. If a certain torque was
exceeded, a handle starts audible skipping and higher torque
is no longer generated. Nowadays, a torque wrench no. 2
with a hexagonal tip of about 0.9 mm (0.035 in.) is used. In
spite of that, it is recommended that the torque wrench sup-
plied by the manufacturer be used for every device because
compatibility of the torque cannot be ensured. In exceptional
cases of exchanging a device with a discharged battery, it is
also possible to use a fixed, nontorque spanner of the given
size for disconnection instead of the torque wrench.
