Use of the anaerobic threshold for evaluating various total artificial heart control algorithms in calves.

In the total artificial heart (TAH) project, choosing the best control mode is an important factor in the design of a completely implantable TAH. Four different control modes for the TAH were evaluated in the same calf using the anaerobic threshold (AT) as an assessment of aerobic capacity, where AT was defined as the oxygen consumption (VO2) at which the relationship between blood lactate measurements and VO2 became nonlinear during progressive treadmill exercise. This new approach tests the integrated response of the central, peripheral, and metabolic regulatory mechanisms to physiological workloads. Preliminary data showed AT in the left master alternatively ejecting mode to be slightly higher than in the other three modes.