Direct compression of the failing heart reestablishes maximal mechanical efficiency.

Carrington, RAJ; Huang, Y; Kawaguchi, O; Yuasa, T; Shirota, K; Martin, D; Hunyor, SN

Direct compression of the failing heart reestablishes maximal mechanical efficiency.

Carrington, RAJ Huang, Y Kawaguchi, O Yuasa, T Shirota, K Martin, D Hunyor, SN

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Publication Type:: Journal Article
Citation:: Ann Thorac Surg, 2003, 75 (1), pp. 190 - 196
Issue Date:: 2003-01

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Field	Value	Language
dc.contributor.author	Carrington, RAJ	en_US
dc.contributor.author	Huang, Y	en_US
dc.contributor.author	Kawaguchi, O	en_US
dc.contributor.author	Yuasa, T	en_US
dc.contributor.author	Shirota, K	en_US
dc.contributor.author	Martin, D	en_US
dc.contributor.author	Hunyor, SN	en_US
dc.date.issued	2003-01	en_US
dc.identifier.citation	Ann Thorac Surg, 2003, 75 (1), pp. 190 - 196	en_US
dc.identifier.issn	0003-4975	en_US
dc.identifier.uri	http://hdl.handle.net/10453/4748
dc.description.abstract	BACKGROUND: In failing hearts, homeostatic mechanisms contrive to maximize stroke work and maintain normal arterial blood pressure at the expense of energetic efficiency. In contrast dobutamine reestablishes maximal mechanical efficiency by promoting energetically optimal loading conditions. However, dobutamine also wastefully increases nonmechanical oxygen consumption. We investigated whether direct mechanical cardiac compression would reestablish maximal mechanical efficiency without the oxygen-wasting effect. METHODS: The pressure-volume relationship and myocardial oxygen consumption were derived in sheep using left ventricular pressure and volume from manometer-tipped and conductance catheters, and coronary flow from Transonics flow probe. RESULTS: Propranolol hydrochloride and atropine sulfate were administered to reduce ejection fraction to 21% when ventricular elastance fell to 1.35 mm Hg/mL and mechanical efficiency to 79% of maximal. Low-pressure direct mechanical compression of the failing heart restored mechanical efficiency to 94% of maximal and realigned optimal left ventricular end-systolic pressure with operating left ventricular end-systolic pressure without altering nonmechanical oxygen consumption. CONCLUSIONS: We conclude that direct cardiac compression restores mechanical efficiency to normal maximum without wasting energy on additional nonmechanical activity.	en_US
dc.language	eng	en_US
dc.relation.ispartof	Ann Thorac Surg	en_US
dc.relation.isbasedon	10.1016/s0003-4975(02)04166-8	en_US
dc.subject.classification	Respiratory System	en_US
dc.subject.mesh	Heart	en_US
dc.subject.mesh	Animals	en_US
dc.subject.mesh	Sheep	en_US
dc.subject.mesh	Heart-Assist Devices	en_US
dc.subject.mesh	Suction	en_US
dc.subject.mesh	Oxygen Consumption	en_US
dc.subject.mesh	Blood Pressure	en_US
dc.subject.mesh	Pressure	en_US
dc.subject.mesh	Models, Theoretical	en_US
dc.subject.mesh	Models, Cardiovascular	en_US
dc.title	Direct compression of the failing heart reestablishes maximal mechanical efficiency.	en_US
dc.type	Journal Article
utslib.citation.volume	1	en_US
utslib.citation.volume	75	en_US
utslib.location.activity	Netherlands	en_US
utslib.for	1103 Clinical Sciences	en_US
utslib.for	1102 Cardiorespiratory Medicine and Haematology	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Medical and Molecular Sciences
utslib.copyright.status	closed_access
pubs.issue	1	en_US
pubs.publication-status	Published	en_US
pubs.volume	75	en_US

Abstract:

BACKGROUND: In failing hearts, homeostatic mechanisms contrive to maximize stroke work and maintain normal arterial blood pressure at the expense of energetic efficiency. In contrast dobutamine reestablishes maximal mechanical efficiency by promoting energetically optimal loading conditions. However, dobutamine also wastefully increases nonmechanical oxygen consumption. We investigated whether direct mechanical cardiac compression would reestablish maximal mechanical efficiency without the oxygen-wasting effect. METHODS: The pressure-volume relationship and myocardial oxygen consumption were derived in sheep using left ventricular pressure and volume from manometer-tipped and conductance catheters, and coronary flow from Transonics flow probe. RESULTS: Propranolol hydrochloride and atropine sulfate were administered to reduce ejection fraction to 21% when ventricular elastance fell to 1.35 mm Hg/mL and mechanical efficiency to 79% of maximal. Low-pressure direct mechanical compression of the failing heart restored mechanical efficiency to 94% of maximal and realigned optimal left ventricular end-systolic pressure with operating left ventricular end-systolic pressure without altering nonmechanical oxygen consumption. CONCLUSIONS: We conclude that direct cardiac compression restores mechanical efficiency to normal maximum without wasting energy on additional nonmechanical activity.

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http://hdl.handle.net/10453/4748