ARTIFICIAL HEART

[seminar class]

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The Artificial Heart: A Design Example
The Human Heart
 Heart has four chambers
 Right chambers pump blood to lungs to receive oxygen
 Left chambers pump oxygenated blood from lungs to rest of the body
 Right and left atria receive blood
 Right and left ventricles pump blood
 Valves produce one-way blood flow from atria ® ventricles ® arteries
 Energy to pump blood comes from nutrients and oxygen in blood
 The blood supply to the heart is provided by coronary arteries
Heart Disease
 Heart attack: blockage of coronary artery damages portion of heart muscle
 Congestive heart failure: gradual weakening of heart
 Millions suffer from heart disease
– Many cases are treatable with lifestyle changes, drugs and/or surgery
– Surviving patients suffering from most severe cases need new hearts!
The Need for a Heart Substitute
 100,000 Americans/year suffering from severe heart disease need new hearts
 Only 2,000 patients receive heart transplants
 Conclusion: many patients die waiting for a new heart!
 A suitable alternative to donor hearts could prolong thousands of lives
History of Heart Substitutes
 WWII: first open heart surgeries
 1953: heart-lung machine successfully used during heart surgery
 1958: Drs. Willem Kolff and Tetsuzo Akutsu sustain a dog for 90 minutes with a PVC artificial heart
 1967: Dr. Christian Barnard transplants a donor heart into a 59 year old man (he survived 18 days)
 1969: Dr. Denton Cooley uses an artificial heart to sustain a patient waiting for a donor (survived 3 days)
 1972: Cyclosporine introduced to suppress immune responses of transplant recipients
 1982: Dr. William DeVries implants the Jarvik-7 artificial heart into Dr. Barney Clark (he survived 112 days)
Why Heart Substitutes Fail
 Immune response “rejects” transplant or side effects due to immune suppression
 Infection due to tubes and wires passing through skin
 Formation of clots
 Damage to red blood cells
 Lack of pulsatile blood flow?
Design Process
 Identify the problem or need to address
 Specify details/criteria of an adequate solution to your problem
 Implement various solutions that meet the criteria you specified
 Test to determine which solution is most viable
 Further testing to refine the solution you chose
Design Refinement
 Process is iterative
– You need to repeat various steps after testing
– Make design changes based on test results
 Failed designs
– Design didn’t meet criteria
– Could be due to inappropriate criteria