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

This Article Full Text Full Text (PDF) 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): David J. Chambers Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bessho, R. Articles by Chambers, D. J. Search for Related Content PubMed PubMed Citation Articles by Bessho, R. Articles by Chambers, D. J. Related Collections Myocardial protection Related Article

J Thorac Cardiovasc Surg 2002;124:340-351
© 2002 The American Association for Thoracic Surgery

Cardiopulmonary Support and Physiology (CSP)

Myocardial protection with oxygenated esmolol cardioplegia during prolonged normothermic ischemia in the rat

From the Cardiac Surgical Research/Cardiothoracic Surgery, The Rayne Institute, Guy's and St Thomas' NHS Trust, St Thomas' Hospital, London, United Kingdom.

Received for publication June 5, 2001. Revisions requested Sept 19, 2001; revisions received Nov 13, 2001. Accepted for publication Nov 20, 2001. Address for reprints: David J. Chambers, PhD, Cardiac Surgical Research/Cardiothoracic Surgery, The Rayne Institute, Guy's and St Thomas' NHS Trust, St Thomas' Hospital, London SE1 7EH, United Kingdom (E-mail: david.chambers{at}kcl.ac.uk).

Objective: We previously showed that arrest with multidose infusions of high-dose (1 mmol/L) esmolol (an ultra-short-acting ß-blocker) in oxygenated Krebs-Henseleit buffer (esmolol cardioplegia) provided complete myocardial protection after 40 minutes of normothermic (37°C) global ischemia in isolated rat hearts. In this study we investigated the importance of oxygenation for protection with esmolol cardioplegia, compared it with that of St Thomas' Hospital cardioplegia, and determined the protective efficacy of multidose esmolol cardioplegia for extended ischemic durations.
Methods: Isolated rat hearts (n = 6/group) were perfused in the Langendorff mode at constant pressure (75 mm Hg) with oxygenated Krebs-Henseleit bicarbonate buffer at 37°C. The first part of the first study had four groups: (i) multidose (every 15 minutes) oxygenated (95% oxygen/5% carbon dioxide) Krebs-Henseleit buffer during 60 minutes of global ischemia, (ii) multidose deoxygenated (95% nitrogen/5% carbon dioxide) Krebs-Henseleit buffer during 60 minutes of global ischemia, (iii) multidose oxygenated esmolol cardioplegia during 60 minutes of global ischemia, and (iv) multidose deoxygenated esmolol cardioplegia during 60 minutes of global ischemia. The second part of the first study had three groups: (v) multidose St Thomas' Hospital solution during 60 minutes of global ischemia, (vi) multidose oxygenated St Thomas' Hospital solution during 60 minutes of global ischemia, and (vii) multidose oxygenated esmolol cardioplegia during 60 minutes of global ischemia. In the second study, hearts were randomly assigned to 60, 75, 90, or 120 minutes of global ischemia and at each ischemic duration were subjected to multidose oxygenated constant flow or constant pressure infusion of (i) Krebs-Henseleit buffer (constant flow), (ii) Krebs-Henseleit buffer (constant pressure), (iii) esmolol cardioplegia (constant flow), or (iv) esmolol cardioplegia (constant pressure). All hearts were reperfused for 60 minutes, and recovery of function was measured.
Results: Multidose infusion of oxygenated esmolol cardioplegia completely protected the hearts (97% ± 5%) after 60 minutes of 37°C global ischemia. Deoxygenated esmolol cardioplegia was significantly less protective (45% ± 8%). Oxygenation of St Thomas' Hospital solution did not alter its protective efficacy in this study (70% ± 4% vs 69% ± 7%). Infusion of esmolol cardioplegia at constant pressure provided complete protection for 60, 75, and 90 minutes (104% ± 5%, 95% ± 5%, and 95% ± 3%, respectively), whereas protection with constant-flow esmolol cardioplegic infusion was significantly decreased at ischemic durations longer than 60 minutes. This decrease in efficacy of constant-flow esmolol cardioplegia was associated with increasing coronary perfusion pressure leading to myocardial injury.
Conclusions: Oxygenation of esmolol cardioplegia (Krebs-Henseleit buffer plus 1.0 mmol/L esmolol) was essential for optimal myocardial protection. Multidose infusion of oxygenated esmolol cardioplegia provided good myocardial protection during extended periods of normothermic ischemia. Esmolol cardioplegia may provide an efficacious alternative to hyperkalemia.

Related Article

Oxygenated multidose delivery of crystalloid esmolol cardioplegia as an alternative to high potassium cardioplegia

James D. McCully
J. Thorac. Cardiovasc. Surg. 2002 124: 219-220. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

				F. Nicolini, C. Beghi, C. Muscari, A. Agostinelli, A. M. Budillon, I. Spaggiari, and T. Gherli Myocardial protection in adult cardiac surgery: current options and future challenges Eur. J. Cardiothorac. Surg., December 1, 2003; 24(6): 986 - 993. [Abstract] [Full Text] [PDF]

				D. J. Chambers Mechanisms and alternative methods of achieving cardiac arrest Ann. Thorac. Surg., February 1, 2003; 75(2): S661 - 666. [Abstract] [Full Text] [PDF]

				J. D. McCully Oxygenated multidose delivery of crystalloid esmolol cardioplegia as an alternative to high potassium cardioplegia J. Thorac. Cardiovasc. Surg., August 1, 2002; 124(2): 219 - 220. [Full Text] [PDF]