HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Francis V. DiPierro Joseph E. Bavaria David J. Polidori Michael A. Acker Timothy J. Gardner Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by DiPierro, F. V. Articles by Gardner, T. J. Search for Related Content PubMed PubMed Citation Articles by DiPierro, F. V. Articles by Gardner, T. J.

Ann Thorac Surg 1996;62:662-669
© 1996 The Society of Thoracic Surgeons

---

Original Articles: Cardiovascular

Triiodothyronine Optimizes Sheep Ventriculoarterial Coupling for Work Efficiency

Division of Cardiothoracic Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania

Background. Triiodothyronine (T₃) administration after cardiopulmonary bypass has been shown to significantly improve cardiac performance. The present study was undertaken to elucidate the effects of T₃, when administered as an intravenous bolus, on both cardiac energetics and stroke work-oxygen utilization (EW/LVVO₂) efficiency.

Methods. In both unstressed and stressed hearts, energetics were evaluated at baseline and 2 hours after intervention in an in vivo sheep preparation. In the first group (n = 5) sheep received saline vehicle. In the second group (n = 9) sheep received an intravenous bolus of 1.2 µg/kg of T₃. In the third group (n = 7) sheep received a 2-hour intravenous infusion of dobutamine at a rate of 5 µg/kg/min.

Results. In the unstressed heart, T₃ improved cardiac function at no cost in oxygen consumption by decreasing afterload and hence improved EW/LVVO₂ efficiency. In contrast, dobutamine improved unstressed cardiac function by increasing contractility at the cost of increased oxygen consumption and thus decreased EW/LVVO₂ efficiency. Triiodothyronine optimized ventriculoarterial coupling for efficiency, but dobutamine optimized coupling for maximal work. In the stressed heart, T₃ again improved EW/LVVO₂ efficiency, but dobutamine had the opposite effect.

Conclusions. The bolus administration of T₃ improves unstressed cardiac performance through optimization of ventriculoarterial coupling for EW/LVVO₂ efficiency, primarily through vasodilation. Triiodothyronine also increases efficiency in the stressed heart. This study supports the use of T₃ in cardiac operations to improve cardiac performance with no cost in oxygen consumption characteristic of inotropic agents.

This article has been cited by other articles:

				F. Vargas, J. M. Moreno, I. Rodriguez-Gomez, R. Wangensteen, A. Osuna, M. Alvarez-Guerra, and J. Garcia-Estan Vascular and renal function in experimental thyroid disorders Eur. J. Endocrinol., February 1, 2006; 154(2): 197 - 212. [Abstract] [Full Text] [PDF]

				M. A. Portman, K. Qian, J. Krueger, and X.-H. Ning Direct action of T3 on phosphorylation potential in the sheep heart in vivo Am J Physiol Heart Circ Physiol, May 1, 2005; 288(5): H2484 - H2490. [Abstract] [Full Text] [PDF]

				A. Ripoli, A. Pingitore, B. Favilli, A. Bottoni, S. Turchi, N. F. Osman, D. De Marchi, M. Lombardi, A. L'Abbate, and G. Iervasi Does subclinical hypothyroidism affect cardiac pump performance?: Evidence from a magnetic resonance imaging study J. Am. Coll. Cardiol., February 1, 2005; 45(3): 439 - 445. [Abstract] [Full Text] [PDF]

				B. Biondi, E. A. Palmieri, G. Lombardi, and S. Fazio Effects of Thyroid Hormone on Cardiac Function - The Relative Importance of Heart Rate, Loading Conditions, and Myocardial Contractility in the Regulation of Cardiac Performance in Human Hyperthyroidism J. Clin. Endocrinol. Metab., March 1, 2002; 87(3): 968 - 974. [Abstract] [Full Text] [PDF]

				B. Stobierska-Dzierzek, H. Awad, and R. E. Michler The evolving management of acute right-sided heart failure in cardiac transplant recipients J. Am. Coll. Cardiol., October 1, 2001; 38(4): 923 - 931. [Abstract] [Full Text] [PDF]

				I. Klein and K. Ojamaa Thyroid Hormone : Targeting the Vascular Smooth Muscle Cell Circ. Res., February 16, 2001; 88(3): 260 - 261. [Full Text] [PDF]

				M. A. Portman, C. Fearneyhough, X.-H. Ning, B. W. Duncan, G. L. Rosenthal, and F. M. Lupinetti Triiodothyronine repletion in infants during cardiopulmonary bypass for congenital heart disease J. Thorac. Cardiovasc. Surg., September 1, 2000; 120(3): 604 - 608. [Abstract] [Full Text] [PDF]

				R. D. Mainwaring, E. Capparelli, K. Schell, M. Acosta, and J. C. Nelson Pharmacokinetic Evaluation of Triiodothyronine Supplementation in Children After Modified Fontan Procedure Circulation, March 28, 2000; 101(12): 1423 - 1429. [Abstract] [Full Text] [PDF]

				N. Murai, Y. Katayama, T. Yamada, T. Imazeki, Y. Irie, H. Kiyama, Y. Sato, I. Hata, H. Yoshida, and M. Mukouyama Thyroid Hormone and Myocardial Metabolism After Heart Surgery in Dogs Asian Cardiovasc Thorac Ann, March 1, 1999; 7(1): 13 - 17. [Abstract] [Full Text] [PDF]

				G. E. Cimochowski, M. D. Harostock, and P. J. Foldes MINIMAL OPERATIVE MORTALITY IN PATIENTS UNDERGOING CORONARY ARTERY BYPASS WITH SIGNIFICANT LEFT VENTRICULAR DYSFUNCTION BY MAXIMIZATION OF METABOLIC AND MECHANICAL SUPPORT J. Thorac. Cardiovasc. Surg., April 1, 1997; 113(4): 655 - 666. [Abstract] [Full Text]