5388 Technical manual
Chapter 2
Precautions
20
Place the wires on the right atrial free wall, oriented along the
direction of the myocardial fibers, approximately 1 cm apart. It is
important to achieve a sensing threshold of at least 1.0 mV. The
atrial sensitivity should be set to a minimum of one-half the
measured threshold. This ensures a minimum safety margin of 2x
the sensing threshold. Failure to follow this procedure can lead to
delivery of asynchronous pulses.
Sensitivity Settings
Since the sensitivity setting determines the smallest signal that
can be sensed by the pacemaker, set the sensitivity dial to
one-half the mV value of the patient’s sensitivity threshold (see
“Sensing Threshold” on page 84). This setting will provide a 2x
safety margin to ensure proper sensing.
A more sensitive setting may be chosen to provide a greater safety
margin. However, be aware that setting the sensitivity value too
low (too sensitive) could result in inappropriate sensing of far field
signals (e.g., sensing of R- or T-waves on the atrial channel or
P-waves on the ventricular channel), leading to inappropriate
inhibition of pacing pulses.
High Output and Maximum Sensitivity
Although the pacemaker contains a safety pacing feature that
prevents inappropriate inhibition of ventricular pacing due to
far-field sensing, the simultaneous use of high output and
maximum sensitivity (i.e., the lowest mV value) should be avoided.
Electrostatic Discharge (ESD)
The pacing lead(s) provides a low-impedance pathway to the
heart. Therefore, it is recommended that attending health care
professionals discharge any static electricity by touching a large
metal or conductive, grounded surface prior to touching the
patient, the cable, the leads or the pacemaker. Also, neutralize any
static electricity from the patient by touching the patient away from
(i.e., distal to) the leads.