Fig. 2

Schematic of the in vitro LV flow circuit. The LV physical model is enclosed within an acrylic box filled with water-glycerin solution. Expansion and contraction of the flexible-walled LV model is accomplished via periodic pressure fluctuations of the enclosing fluid using a programmable piston pump (PPP). Flow probes F1 and F2 are used to measure mitral and aortic flow rates, respectively. Measurement locations of two transducers for measurement of LV (P1) and aortic pressures (P2) are indicated. St. Jude Regent BMHVs were used in the mitral and aortic valve positions. The flow direction through the LV model is indicated using a dashed arrow.