Noninvasive control of cardiac output for alternately ejecting dual-pusherplate pumps

An artificial heart should be controlled in a noninvasive fashion; the presence of the control system should pose no risk to the patient. Ideally, much of the control function would be attained passively, by designing the pumps and energy converter so that they naturally respond in an appropriate manner to changes in the circulation. We present methods of controlling both left-right output balance and providing response to changing demands for blood flow for a class of total artificial hearts with implanted energy converters. Our balance control actively maintains left-right balance, but does so in concert with the natural response of the pumps to changes in filling pressures. Cardiac output (CO) can be made to be sensitive to right atrial pressure, but peripheral resistance is our usual cue. Alternative means of determining the correct cardiac output are discussed.