Page 590 - Handbook of Biomechatronics

Pacemakers 581

Fig. 10 Block diagram of a modern pacemaker.

model details. Some models also include radio opaque symbols of a charac-
teristic shape so that the device can easily be identified from an X-ray image.

5.1 Pulse Generators
The pulse generator contains a power source, output electronics, and sensing
and timing electronics, with rate-responsive pulse generators including
movement or breathing sensors and the relevant processing electronics.

5.2 Sensing Electronics

Sensing refers to the identification of heart-generated signals. The specific
signal of interest is the intrinsic cardiac depolarization from the chamber,
or chambers, in which the leads are placed (the R- and P-waves). It is critical
that the electronics can discriminate between these events and those caused
by electrical interference such as diastolic potentials, skeletal muscle contrac-
tion, and, of course, pacing stimuli.