AJP - Heart AJP: Heart and Circulatory Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Heart Circ Physiol 277: H65-H73, 1999;
0363-6135/99 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mikane, T.
Right arrow Articles by Suga, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mikane, T.
Right arrow Articles by Suga, H.
Vol. 277, Issue 1, H65-H73, July 1999

O2 cost of contractility but not of mechanical energy increases with temperature in canine left ventricle

Takeshi Mikane1,2, Junichi Araki1, Shunsuke Suzuki1,2, Ju Mizuno1,2, Juichiro Shimizu1, Satoshi Mohri1,3, Hiromi Matsubara1,3, Masahisa Hirakawa2, Tohru Ohe3, and Hiroyuki Suga1

Departments of 1 Physiology II, 2 Anesthesiology and Resuscitology, and 3 Cardiovascular Medicine, Okayama University Medical School, Okayama 700-8558, Japan

We investigated the effects of myocardial temperature on left ventricular (LV) mechanoenergetics in the excised, cross-circulated canine heart. We used the framework of the LV contractility (Emax)-pressure-volume area (PVA; a measure of total mechanical energy)-myocardial oxygen consumption (VO2) relationship. We have shown this framework to be useful to integrative analysis of the mechanoenergetics of a beating heart. In isovolumic contractions at a constant pacing rate, increasing myocardial temperature from 30 to 40°C depressed Emax and increased the oxygen cost of Emax, which was enhanced by dobutamine, in a linear manner. However, the slope of the VO2-PVA relation (reciprocal of contractile efficiency) and its VO2 intercept remained constant. Q10 values of Emax, the oxygen cost of Emax, and the oxygen cost of PVA were 0.4, 2.1 and 1.0, respectively, around normothermia. We conclude that the temperature-dependent processes of cross-bridge cycling and Ca2+ handling integratively depress Emax and augment its oxygen cost without affecting the oxygen cost of PVA as myocardial temperature increases by 10°C around normothermia.

end-systolic pressure-volume relation; pressure-volume area; myocardial oxygen consumption; contractile efficiency


This article has been cited by other articles:


Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
J. Mizuno, J. Araki, S. Suzuki, S. Mohri, T. Mikane, J. Shimizu, H. Matsubara, M. Hirakawa, T. Ohe, and H. Suga
Temperature-dependent postextrasystolic potentiation and Ca2+ recirculation fraction in canine hearts
Am J Physiol Heart Circ Physiol, February 1, 2002; 282(2): H403 - H413.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
A. Saeki, Y. Goto, K. Hata, T. Takasago, T. Nishioka, and H. Suga
Negative inotropism of hyperthermia increases oxygen cost of contractility in canine hearts
Am J Physiol Heart Circ Physiol, December 1, 2000; 279(6): H2855 - H2864.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online