On the Minimum Work Criterion in Optimal Control Models of Left-Ventricular Ejection

This paper deals with models of left-ventricular ejection which are based on the hypothesis of optimal performance. The assumptions made in the models published so far are analyzed, and some major modeling difficulties are discussed. In most of the models, the term describing the external work done by the left ventricle during ejection is included in the optimality criterion. In this paper, the minimum external work criterion is analyzed by comparing the values of external work for different theoretical ejection patterns. The ejection patterns used in the comparisons must satisfy certain feasibility and normalization conditions. The results show that an ejection pattern with the peak flow in the first half of ejection, which resembles the experimental observations, is optimal with respect to minimizing the external work. An ejection pattern with the peak flow in the second half of ejection is the least efficient of the patterns studied.