title: A physical analog of the failing left ventricle for in vitro studies of mechanical wall actuation.
abstract: Mechanical repowering of a failing heart with devices or skeletal muscle could circumvent blood-pump lining problems. Requirements are complex: indefinite support with preservation of valve competence and coronary flow, avoidance of wall coaptation, and allowance of both rapid low impedance refilling and independent left and right pressures. An accurate in vitro physical failing-heart analog could facilitate the choice and screening of surgical and engineering approaches in mock circulation experiments. Prosthetic models, transplant recipient hearts, normal animal hearts, existing in vivo animal failure models, and failing cadaver hearts all have serious limitations. One hundred and four excised porcine hearts were dilated and fixed by three iterative protocols. Geometric and passive mechanical parameters were assessed and compared with targets expected for an end-stage failing heart. For Protocol 3, Subgroup 2 (reinforcing valve support, dilatation by compliant ventricular balloon, and ethyl alcohol fixation), the left ventricular shape and capacity (ellipsoid, 201-377 ml/500 g of heart weight), passive valve function, wall flexural rigidity (Et3 range 0.101-0.331 Nm), and refilling mechanics (99 +/- 17.46 ml during 200-400 ms at < or = 10 mm Hg transmural gradient) were all within goal criteria.
authors.affiliation: Mechanical Circulatory Support Laboratory, University of Cincinnati, Ohio, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Melvin
authors.forename: H
authors.initials: H
authors.lastname: Schima
authors.forename: U M
authors.initials: UM
authors.lastname: Losert
authors.forename: H
authors.initials: H
authors.lastname: Stöhr
authors.forename: H
authors.initials: H
authors.lastname: Siegl
authors.forename: L
authors.initials: L
authors.lastname: Huber
authors.forename: D L
authors.initials: DL
authors.lastname: Glos
authors.forename: E
authors.initials: E
authors.lastname: Wolner
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002314:Cardioplegic Solutions; D002404:Catheterization; D003326:Coronary Circulation / Q000502:physiology; D006321:Heart / Q000033:anatomy & histology / Q000502:physiology; D006333:Heart Failure / Q000503:physiopathology*; D006354:Heart, Artificial / Q000592:standards; D066298:In Vitro Techniques; D008943:Mitral Valve / Q000502:physiology; D013552:Swine; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D002314:Cardioplegic Solutions