Biomedical Engineering Reference
In-Depth Information
compression device that can be implanted external to the patient's heart and partly
sutured to the heart without contacting or interfering with the internal blood
circulation. Thus, the potential IPMNC device can avoid thrombosis and similar
complications common to current artificial heart or heart-assist devices, which
may arise when the blood flow makes repeated contacts with nonbiological or
nonself-surfaces.
In compressing a heart ventricle, the device must be soft and electronically robust
in order not to damage the ventricle. This means that the device should contain
control means such as bradycardic (pacing) and tachyarrhythmic (cardiovert-
ing/defibrillating) to facilitate device operation in synchronism with the left ventric-
ular contraction and should be capable of transcutaneous recharging of the implanted
batteries. The general idea is presented in figure 9.10. Note that the device is
implanted essentially in the ribcage of the patient but is supported on a slender
flexible stem that extends to the abdomen. The stem allows the systolic and diastolic
cycles of the heart to continue and yet allows the body of the heart to make swinging
motions to one side or the other without unnecessary restriction. It is also possible
to place the supporting structure of the heart compression device on the diaphragm
muscle. These details can be worked out during the clinical testing and operation of
such devices.
Note in figure 9.38 that
42
is the patient body,
44
is the abdomen area,
46
is the
ribcage,
5
is the heart,
3
is the polymeric compression finger made with IPMNCs,
30
is the base of the compression device,
10
is a slender conduit carrying the
electronic wires to the muscle and acting as a flexible support column, and
12
is the
power/microprocessor housing placed in the abdomen.
Figure 9.39 depicts a more detailed drawing of the compression device. Again
3
denotes the compression fingers made with IPMNCs,
5
is the heart,
4
depicts an
42
5
3
30
46
10
12
44
FIGURE 9.38
General configuration for the proposed heart compression device.
