1. P10021 – Miniaturization Team
The Miniaturized System
System Architecture
LVAD Concepts
Case Research
Circuitry Research
Microcontroller Research
10/2/2009
Evan Sax
Lowell Smoger
Christine Stone
Mike Calve

2. The Miniaturized System
Overall electronics package size with currently used components can be reduced to approximately
8 x 6.5 x 2.5 inches (130 ci)
Using miniaturized components and removing unnecessary shows an estimated package size of
6.5 x 5 x 2 inches (65 ci)
Device can be distributed into multiple cases
Potential for certain cases to be implanted

3. Estimations on Allowable Implant Dimensions
Abdominal x-ray provides components sizes estimates (referenced to pelvic dimensions):
Electronics package dimensions:
4 x 4 inches
Heart pump dimensions:
3.5 x 4.5 inches
Coronal (front) plane dimension immeasurable
Studies provide empirical date for allowable intrathoracic dimensions[1]:
Model size seemed to be constrained to:
17.5 x 10.5 x 3.8 cm
42.61 cubic inches
Current pump volume:
2 x 2 x 4 inches
16 cubic inches
Figure from Book: Heart Replacement: Artificial Heart 7

4. Concept 1: Centralized Electronics Package w/ External & Separate Battery
Example Single Case Size: 6.5 x 5 x 2 inches (65 ci)
Pros
Minimal outer body components
Increased Maneuverability and QOL
Decreased risk of device damage due to impact & particle ingress
Cons
Serviceability: Components not easily replaced/updated
Data acquisition and programmability
Depending on requirements for microcontroller interaction
Size constraints in body
Limitations on feasible size
Space consumed by LVAD decreases usable space
May be overcome with proper distribution (concept 2)
Heat generation
Cost
Biocompatible materials
Cost of size reduction
Conclusion:
Not within scope of project
May be too big to implant in one particular place
New lines out for user Interface

5. Concept 2: Multi-case Electronics Package with Partial Implant; Battery External & Separate
Case 1 (External): Micro-controller, USB port, Converter(s), Relay(s)
Approximate Size: 5.5 x 5 x 3 inches (82.5 ci) Marginal
Case 2 (Internal): PWM Amps, Motor Controller, Differential Amps
Approximate Size: 5.5 x 2.5 x 1.5 inches (20.6 ci) Ideal
Pros
Increased maneuverability compared to completely external (concept 3)
Potential for fewer wires through body (wireless transmission)
Battery can be included in external case
Serviceable/Updateable external components
No limit on external case size means easier to design and increased likelihood of success
Cons
Items outside are easier to damage
Items in body more difficult to service
Limited Space in Body
Discomfort with internal components
Conclusion
Research shows within acceptable implant limits
Benefits patient
Within scope of project
Concerns with part life inside body
Potential need for larger than expected components could make infeasible

6. Concept 3: Centralized External Electronics Package; Battery External & Separate
Example Single Case Size: 6.5 x 5 x 2 inches (65 ci)
Pros
Reduces case size
No internal component issues (i.e. part failures)
Ease of design
Easier component changeability/upgrade/maintenance
No bio-compatibility issues
No internal health issues (i.e. case leaks)
Cons
Slightly more Impedance
More wires through the body; greater risk of infection
Greater risk for component damage
Perceived weight is greater
Wire connecting battery to controller
Conclusion
This option can be a backup for concept 2

7. Concept 4: Centralized External Electronics Package; Battery Included
Example Single Case Size: 6.5 x 5 x 2 inches (65 ci)
Pros (compared to Concept 3)
None/shorter connecting wire
Protected Battery
Cons (compared to Concept 3)
Larger case size
Weight not as balanced on body
Overall Size
Conclusion
If it is found that all components need to be in the same case, then this option will become more appropriate.

8. System Architecture – Diagram
Signal
Power
System Architecture – Diagram
Current
Subsystem
MICROCONTROLLER
USER INTERFACE
A/D Converters
PWM Signal Gen
Speed/Power Control
Battery
Meter
FUNCTIONAL OR PHYSICAL ELEMENTS
INTERMEDIATE ELECTRONICS
POWER SUPPLY
PWM Amps
Diff Amps
Converters
Motor Controller
Relays
Battery
OUT TO PUMP
IN FROM PUMP

9. Bibliography
[1] T. Mussivand, et al., "Critical Anatomic Dimensions for Intrathoracic Circulatory Assist Devices %J Artificial Organs," vol. 16, pp , 1992.
[2] P. J. Hendry, et al., "The HeartSaver left ventricular assist device: an update," The Annals of Thoracic Surgery, vol. 71, pp. S166-S170, 2001.
[3] L. K. Fujimoto, et al., "Anatomical Considerations in the Design of a Long-Term Implantable Human Left Ventricle Assist System. J Artificial Organs," vol. 9, pp , 1985.
[4] T. V. Mussivand, R. G. Masters, P. J. Hendry, and W. J. Keon, "Totally implantable intrathoracic ventricular assist device," The Annals of Thoracic Surgery, vol. 61, pp , 1996.
[5] T. Mussivand, P. J. Hendry, R. G. Masters, M. King, K. S. Holmes, and W. J. Keon, "Progress with the HeartSaver ventricular assist device," The Annals of Thoracic Surgery, vol. 68, pp , 1999.
[6] R. D. Dowling, A. S. Ghaly, and L. A. Gray, "Creation of a diaphragm patch to facilitate placement of the AbioCor implantable replacement heart," The Annals of Thoracic Surgery, vol. 77, pp , 2004.