1. Thermal Analysis Assumptions: Body Temperature (Environment) is 37˚C Heat distribution on outside of device will be modeled via FEA Heat transfer method inside body is conduction All energy inefficiencies result in heat generation Device is surrounded my muscle tissue which is at equilibrium between perfusion and heat generation

2. Additional 1-D Assumptions 1 dimension normal to the skin Uniform heat generation Constant Properties Body is at equilibrium (neglect heat generation effects) Steady State

3. Data Reference Temperatures[C]: Body Temp= 37 C Ambient Air Temp= 25 C Conduction Coefficients : Internal Organs and Muscle = 0.500 W/m*K Skin and Fat=0.300 W/m*K Titanium=19.000 W/m*K (P13022 only) Clothing=0.029 W/m*K Convection Coefficients [W/m*K]: Air=10.000

4. Critical Values The purpose of our thermal model is to ensure this device will not harm the patient. With a factor of safety of 2, our maximum heat flux through the tissue is 40mW/cm 2

5. 1-D Analysis Model

6. Results

7. Conduction Internal Environment (Abdomen Muscle) Engineering Model Device Boundary Temp: 37˚C The Device will be implanted in abdomen muscle Assuming a worst case scenario, the device will be surrounded by muscle tissue in all directions for an “infinite” thickness. An ANSYS model which includes the boundary temperature of 37˚C and all muscle properties will show worst case temperature and flux conditions

8. Summary For the given area of 64cm 2, 0.3 W (4.67mW/cm 2 ) of heat generation will be dissipated before exceeding 40 o C. For a surface area of 340cm 2 we should be allowed to generate up to 13.6 W of heat energy within the device. Expected worst case heat generation = 2 W.

9. Conclusion The Internal Battery Storage Device is not likely to harm the body through heat generation based upon the of energy flux through the total surface area. Further analysis will be conducted (in ANSYS) to confirm the results. Due to the extreme difficulty of finding a relatively accurate model for the body in relation to the LVAD system, the 1-D analysis is only useful for worst case results and only provide limited useful data. Further analysis in ANSYS should provide more reliable results. Development of the P13022 device should continue with minimal design change.