(a) Effect of varying LVAD support on LV Stroke Work Index (SWI) for four heart failure simulation cases.

<p>The red dots signify Optimal unloading, denoted with corresponding LVAD speed (kRPM). (b) Unimodal (ascending-descending) preload response resembles clinically observed severe LV dysfunction reported by Ross and Braunwald <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0085234#pone.0085234-Ross1" target="_blank">[12]</a>. The shaded region indicates envelope of marked heart dysfunction defined by Ross and Braunwald, and based on the response of LV SWI to volume unloading in five of their patients (JW, MD, CC, IG, RS).