Hierarchical control of heart-assist devices

Cardiovascular disease is a major health problem and heart transplantation has become an accepted method to treat severe cases of the disease. However, the demand for transplantable heart exceeds the supply. When pharmacological treatment fails to maintain adequate blood circulation, mechanical assistance of one or both ventricles is the only available therapy other than transplantation. Improvements in the design and reliability of mechanical assist devices have made long-term implantation feasible. Obtaining information regarding the status of the patient's cardiovascular system is critical in implementing such devices.