A PHYSICAL ANALOG OF THE FAILING LEFT-VENTRICLE FOR IN-VITRO STUDIES OF MECHANICAL WALL ACTUATION

Mechanical repowering of a failing heart with devices or skeletal musc le could circumvent blood-pump lining problems. Requirements are compl ex: indefinite support with preservation of valve competence and coron ary flow, avoidance of wall coaptation, and allowance of both rapid lo w impedance refilling and independent left and right pressures. An acc urate in vitro physical failing-heart analog could facilitate the choi ce and screening of surgical and engineering approaches in mock circul ation experiments. Prosthetic models, transplant recipient hearts, nor mal animal hearts, existing in vivo animal failure models, and failing cadaver hearts all have serious limitations. One hundred and four exc ised porcine hearts were dilated and fixed by three iterative protocol s. Geometric and passive mechanical parameters were assessed and compa red with targets expected for an end-stage failing heart. For Protocol 3, Subgroup 2 (reinforcing valve support, dilatation by compliant ven tricular balloon, and ethyl alcohol fixation), the left ventricular sh ape and capacity (ellipsoid, 201-377 ml/500 g of heart weight), passiv e valve function, wall flexural rigidity (Et(3) range 0.101-0.331 Nm), and refilling mechanics (99 +/- 17.46 ml during 200-400 ms at less th an or equal to 10 mm Hg transmural gradient) were all within goal crit eria.