ATS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

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 Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Michael D. Diodato
Richard B. Schuessler
Ralph J. Damiano, Jr
Jennifer S. Lawton
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mizutani, S.
Right arrow Articles by Lawton, J. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mizutani, S.
Right arrow Articles by Lawton, J. S.
Related Collections
Right arrow Myocardial protection

Ann Thorac Surg 2006;81:154-159
© 2006 The Society of Thoracic Surgeons

Original article: Cardiovascular

Hyperkalemic Cardioplegia-Induced Myocyte Swelling and Contractile Dysfunction: Prevention by Diazoxide

Shinichi Mizutani, MD, Ashraf S. Al-Dadah, MD, Jeffrey B. Bloch, BA, Sandip M. Prasad, MPhil, MD, Michael D. Diodato, MD, Richard B. Schuessler, PhD, Ralph J. Damiano, Jr, MD, Jennifer S. Lawton, MD *

Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri

Accepted for publication June 20, 2005.

* Address correspondence to Dr Lawton, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8234, St. Louis, MO 63110-1013 (Email: lawtonj{at}msnotes.wustl.edu).

BACKGROUND: Hyperkalemic cardioplegia (9°C) results in significant myocyte swelling and reduced contractility, representing a possible mechanism of myocardial stunning. Adenosine triphosphate–sensitive potassium channel (KATP) openers have been shown to ameliorate stunning. This study evaluated the hypothesis that a KATP opener would prevent hyperkalemic cardioplegia-induced myocyte swelling and reduced contractility.

METHODS: Isolated rabbit myocytes were perfused with 37°C Tyrode's solution for 20 minutes, followed by test solution (9°C or 37°C) including control Tyrode's, Tyrode's + 100 µmol/L diazoxide (KATP opener), St. Thomas's solution; or 9°C St. Thomas's + 100 µmol/L diazoxide or St. Thomas's + 100 µmol/L diazoxide + 20 µmol/L HMR1098 or 50 µmol/L 5-hydroxydeconoate (KATP blockers) for 20 minutes (n = 8 per group). Myocytes were then reexposed to 37°C Tyrode's solution for 20 minutes. Volume and contractility were measured by videomicroscopy and video-based edge detection, respectively.

RESULTS: St. Thomas's solution (9°C) caused significant myocyte swelling and associated reduced contractility (p < 0.05). The addition of diazoxide abolished myocyte swelling (p < 0.0001), and eliminated the associated reduced contractility (p < 0.05). Findings were unchanged by the addition of HMR 1098 and 5-hydroxydeconoate.

CONCLUSIONS: Diazoxide prevented myocyte swelling and reduced contractility secondary to hyperkalemic cardioplegia, and this was unchanged by the addition of either KATP channel blocker. Prevention of myocyte swelling was associated with improved contractility, consistent with the hypothesis that myocyte swelling may be a mechanism of myocardial stunning. Diazoxide may play a role in myocyte volume homeostasis by means of a mechanism separate from opening the KATP channel.




This article has been cited by other articles:


Home page
 J. Thorac. Cardiovasc. Surg.Home page
T. L. Butler, J. R. Egan, F. G. Graf, C. G. Au, A. C. McMahon, K. N. North, and D. S. Winlaw
Dysfunction induced by ischemia versus edema: Does edema matter?
J. Thorac. Cardiovasc. Surg., July 1, 2009; 138(1): 141 - 147.
[Abstract] [Full Text] [PDF]

Home page
 HeartHome page
T Bragadeesh, A R Jayaweera, M Pascotto, A Micari, D E Le, C M Kramer, F H Epstein, and S Kaul
Post-ischaemic myocardial dysfunction (stunning) results from myofibrillar oedema
Heart, February 1, 2008; 94(2): 166 - 171.
[Abstract] [Full Text] [PDF]

Home page
 Ann. Thorac. Surg.Home page
A. S. Al-Dadah, R. K. Voeller, R. B. Schuessler, R. J. Damiano Jr, and J. S. Lawton
Maintenance of Myocyte Volume Homeostasis During Stress by Diazoxide is Cardioprotective
Ann. Thorac. Surg., September 1, 2007; 84(3): 857 - 862.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ANN THORAC SURG ASIAN CARDIOVASC THORAC ANN EUR J CARDIOTHORAC SURG
J THORAC CARDIOVASC SURG ICVTS ALL CTSNet JOURNALS
Copyright © 2006 by The Society of Thoracic Surgeons.