The HeartBeat(tm)

TEAM 4 (Hufflepuff) - Section 501

Members:
- Jackie Boone
- Karl Hahn
- Parth Khade
- Timothy Snowden
- Krista Volberding
- Chris Weyand
- Katherine Wood
- Jeremy Wurbs
- Shane Young

MAIN PRINCIPLE: Mimic the heart's natural function.
- The design was optimized for laminar flow to avoid hemolysis and thrombogenesis.
- Creates pulsatile flow to maintain healthy vasculature.

LAYOUT:
- Divided into two main sides, similar to the right and left heart.
- Each side has an 'atrium' and a 'ventricle'.
- The flow of blood and contraction system is nearly identical to that of the heart, with blood entering the atria, then the ventricles, from which it is ejected during systole. Below is an animation of the ventricle pumping:

CONTRACTILE MATERIAL:
- Dielectric electroactive polymer (d-EAP): a 'compliant capacitor' - a thin layer of elastomer sandwiched between two compliant electrodes.
- Expands when a voltage is applied to it, corresponding to muscular relaxation (diastole).
- Removal of voltage causes the d-EAP to return to its original shape, providing a contractile force corresponding to muscular contraction (systole)
- Embedded in the ventricle (see image -- red layer is the contractile material)

- Both atria and right ventricle use a 'low' compliance elastomer in the d-EAP. This provides a low force of contraction, yielding a low pressure.
-Time lag from differing forces avoided by using atria to collect blood while ventricles are contracting and relaxing ... like normal heart.
- Left ventricle uses a 'high' compliance elastomer, providing a high contraction force, yielding a high pressure.
- High d-EAP strain range (10-215%) allows for wide range of stroke volumes with one device
- Natural muscle range falls within force & strain range of d-EAP

BODY-DEVICE INTERFACE
- Elast-Eon(tm) is used for all body contact -- blood and organs.
- Completely biocompatible and non-calcific
- High durability & long life (25 years)

CONTROL & ENERGY SYSTEM
- TET System is used for power supply
- Voltage amplifier increases voltage to level necessary for d-EAP
- Pacemaker used for control -- powered by TET system
- Allows for modification by doctor -- can change stroke volume, heart rate, etc.
- Pacemaker also adjusts heart rate based on physical activity using a piezoelectric crystal sensitive to mechanical stress