Definition: Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
Input: Abstract: A new optimization model for explaining the observed left ventricular ejection patterns is presented. In the system model, arterial load is described by a modified windkessel load. The ejection pattern for a given cardiac output with fixed stroke volume and duration of ejection is predicted by minimizing a criterion that describes the total ventricular O2 consumption. The ejection patterns of the model closely resemble the observed ejection patterns. Also, the model predictions for changes in the values of the system parameters are qualitatively correct. The results strongly suggest that the control of ejection pattern satisfies the principle of energy cost minimization.

Energy cost minimization in left ventricular ejection: an optimal control model.