Figure 6.

Hemodynamics (pressure and flow) and pressure-volume (PV) loop responses to a step-change in pulmonary vascular resistance in the closed-loop simulation. When pulmonary vascular resistance is increased from 1 to 2 Wood units, the continuous flow overpumps the circulation resulting in low ventricular volumes and ventricular suction events. TORVAD counterpulse support preserves aortic valve flow that physiologically responds to the change in preload, which reduces cardiac output and prevents overpumping.