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Functional Modeling of Normal and CHF Heart and Control of Total Artificial Heart- An Optimizing Approach

Ravanshadi, Samin | 2013

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 44399 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Jahed, Mehran
  7. Abstract:
  8. World-wide, Congestive Heart Failure (CHF) takes hundreds of thousands of lives each year. This chronic heart disease causes poor performance of the heart and insufficient blood pumping to the organs. A significant percentage of patients with CHF require heart transplants for their survival. The high cost of heart transplant, shortage of donor hearts and possibility of its rejection by recipients are serious problems of this type of treatment. Therefore a large number of heart patients are potential beneficiaries of artificial blood pumps such as Ventricular Assist Device (VAD) and Total Artificial Heart (TAH). Performance of these systems must be compliant and complementary to the existing vasculature system. To study the operation of these devices, one needs to include their model within the existing blood circulation system, and adequately identify and distinguish their subsystems. In this study characteristics of normal physiological function of the heart was compared to the CHF one and the modified model inclusive of the proposed artificial pump was introduced. In all such evaluations, the pressure-volume (PV) modeling of the system was simulated to evaluate physiological functionalities of the proposed systems. One of the problems with the usage of artificial pumps is its tendency to produce blood clots as a result of pumping pulsations. In this work, mathematical model of blood clot was introduced and simulated in particular to study the effect of pulsating flow. To evaluate the full functionality of the proposed artificial pumps, a complete model of the blood circulation systems inclusive of VAD and TAH was analyzed. This analysis included a DC rotary machine model for a LVAD and a linear electric machine for TAH. Controller design for LVAD and TAH were performed with respect to the changing physiological states and system variables. To adequately control the LVAD and TAH, a robust adaptive controller was introduced. The proposed controller proved to be superior as it was able to address the parameter uncertainties and external load disturbances with acceptable tracking performance, dynamic response and stability. In this regard, simulation results of the mean Ejection Fraction (EF) for the normal circulation state were 73, 65 and 69 percent for normal heart, LVAD and TAH, respectively, while the EF for normal CV system in clinic settings was reported at 71 percent. These results demonstrate that application of robust adaptive control for the proposed LVAD and TAH, under dictated parameter variations and external disturbances of human physiological system, was quite successful
  9. Keywords:
  10. Total Artificial Heart ; Congestive Heart Failure (CHF) ; Robust Adaptive Controller ; Ejection Fraction

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