title: Measuring the mechanical efficiency of a working cardiac muscle sample at body temperature using a flow-through calorimeter.
abstract: We have developed a new `work-loop calorimeter' that is capable of measuring, simultaneously, the work-done and heat production of isolated cardiac muscle samples at body temperature. Through the innovative use of thermoelectric modules as temperature sensors, the development of a low-noise fluid-flow system, and implementation of precise temperature control, the heat resolution of this device is 10 nW, an improvement by a factor of ten over previous designs. These advances have allowed us to conduct the first flow-through measurements of work output and heat dissipation from cardiac tissue at body temperature. The mechanical efficiency is found to vary with peak stress, and reaches a peak value of approximately 15 %, a figure similar to that observed in cardiac muscle at lower temperatures.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Taberner
authors.forename: Callum M
authors.initials: CM
authors.lastname: Johnston
authors.forename: Toan
authors.initials: T
authors.lastname: Pham
authors.lastname: June-Chiew Han
authors.forename: Bryan P
authors.initials: BP
authors.lastname: Ruddy
authors.forename: Denis S
authors.initials: DS
authors.lastname: Loiselle
authors.forename: Poul M F
authors.initials: PM
authors.lastname: Nielsen
mesh_terms: D001831:Body Temperature; D001833:Body Temperature Regulation; D002151:Calorimetry; D006358:Hot Temperature; D009206:Myocardium; D013696:Temperature