title: A high-resolution thermoelectric module-based calorimeter for measuring the energetics of isolated ventricular trabeculae at body temperature.
abstract: Isolated ventricular trabeculae are the most common experimental preparations used in the study of cardiac energetics. However, the experiments have been conducted at subphysiological temperatures. We have overcome this limitation by designing and constructing a novel calorimeter with sufficiently high thermal resolution for simultaneously measuring the heat output and force production of isolated, contracting, ventricular trabeculae at body temperature. This development was largely motivated by the need to better understand cardiac energetics by performing such measurements at body temperature to relate tissue performance to whole heart behavior in vivo. Our approach uses solid-state thermoelectric modules, tailored for both temperature sensing and temperature control. The thermoelectric modules have high sensitivity and low noise, which, when coupled with a multilevel temperature control system, enable an exceptionally high temperature resolution with a noise-equivalent power an order of magnitude greater than those of other existing muscle calorimeters. Our system allows us to rapidly and easily change the experimental temperature without disturbing the state of the muscle. Our calorimeter is useful in many experiments that explore the energetics of normal physiology as well as pathophysiology of cardiac muscle.
authors.affiliation: Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; and c.johnston@imperial.ac.uk.
authors.forename: Callum M
authors.identifier: http://orcid.org/0000-0002-6773-9884
authors.initials: CM
authors.lastname: Johnston
authors.affiliation: Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; and.
authors.forename: June-Chiew
authors.initials: JC
authors.lastname: Han
authors.affiliation: Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; and Department of Engineering Science, The University of Auckland, Auckland, New Zealand.
authors.forename: Bryan P
authors.initials: BP
authors.lastname: Ruddy
authors.affiliation: Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; and Department of Engineering Science, The University of Auckland, Auckland, New Zealand.
authors.forename: Poul M F
authors.initials: PM
authors.lastname: Nielsen
authors.affiliation: Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; and Department of Engineering Science, The University of Auckland, Auckland, New Zealand.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Taberner
mesh_terms: D000818:Animals; D001831:Body Temperature; D002151:Calorimetry / Q000295:instrumentation*; D004734:Energy Metabolism; D004867:Equipment Design; D006352:Heart Ventricles / Q000378:metabolism*; D066298:In Vitro Techniques; D008422:Materials Testing; D009119:Muscle Contraction; D051381:Rats; D015203:Reproducibility of Results; D016278:Ventricular Function, Right
keywords: heat production; microcalorimetry; muscle energetics