An innovative work-loop calorimeter for in vitro measurement of the mechanics and energetics of working cardiac trabeculae

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dc.contributor.author Taberner, Andrew en
dc.contributor.author Han, June en
dc.contributor.author Loiselle, Denis en
dc.contributor.author Nielsen, Poul en
dc.date.accessioned 2011-12-04T22:41:28Z en
dc.date.accessioned 2011-12-08T18:22:23Z en
dc.date.issued 2011 en
dc.identifier.citation Journal of Applied Physiology 11(6) pp. 1798-1803 Dec 2011 en
dc.identifier.issn 8750-7587 en
dc.identifier.uri http://hdl.handle.net/2292/9903 en
dc.description.abstract We describe a unique work-loop calorimeter with which we can measure, simultaneously, the rate of heat production and force-length work output of isolated cardiac trabeculae. The mechanics of the force-length work-loop contraction mimic those of the pressure-volume work-loops experienced by the heart. Within the measurement chamber of a flow-through microcalorimeter, a trabecula is electrically stimulated to respond, under software control, in one of three modes: fixed-end, isometric, or isotonic. In each mode, software controls the position of a linear motor, with feedback from muscle force, to adjust muscle length in the desired temporal sequence. In the case of a work-loop contraction, the software achieves seamless transitions between phases of length control (isometric contraction, isometric relaxation, and restoration of resting muscle length) and force control (isotonic shortening). The area enclosed by the resulting force-length loop represents the work done by the trabecula. The change of enthalpy expended by the muscle is given by the sum of the work term and the associated amount of evolved heat. With these simultaneous measurements, we provide the first estimation of suprabasal, net mechanical efficiency (ratio of work to change of enthalpy) of mammalian cardiac trabeculae. The maximum efficiency is at the vicinity of 12%. en
dc.format.medium 6 en
dc.relation.ispartofseries Journal of Applied Physiology en
dc.relation.replaces http://hdl.handle.net/2292/9762 en
dc.relation.replaces 2292/9762 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from http://www.sherpa.ac.uk/romeo/issn/0021-8987/ en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.subject work heat enthalpy efficiency microcalorimeter en
dc.title An innovative work-loop calorimeter for in vitro measurement of the mechanics and energetics of working cardiac trabeculae en
dc.type Journal Article en
dc.identifier.doi 10.1152/japplphysiol.00752.2011 en
pubs.begin-page 1798 en
pubs.volume 111 en
dc.rights.holder Copyright: American Physiological Society en
dc.identifier.pmid 21903883 en
pubs.end-page 1803 en
dc.rights.accessrights http://purl.org/eprint/accessRights/RestrictedAccess en
pubs.subtype JOUR en
pubs.elements-id 225013 en
pubs.org-id Bioengineering Institute en
pubs.org-id ABI Associates en
pubs.org-id Engineering en
pubs.org-id Engineering Science en
pubs.org-id Science en
pubs.org-id Science Research en
pubs.org-id Maurice Wilkins Centre (2010-2014) en
pubs.record-created-at-source-date 2011-12-04 en
pubs.dimensions-id 21903883 en


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