Effect of repetitive ischemia on myocardial oxygen tension in isolated perfused and hypoperfiised rat hearts

✍ Scribed by Bruce J. Friedman; Oleg Y. Grinberg; Kimberly A. Isaacs; Enno K. Ruuge; Harold M. Swartz

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 644 KB
• Volume: 35
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910350213

✦ Synopsis

Abstract

The objective of this study was to determine the effects of repetitive ischemia on myocardial oxygen tension (pO~2~), consumption, and delivery in crystalloid normoperfused (perfu‐sion pressure > 70 mmHg) and hypoperfused (perfusion pressure ˜50 mmHg) constant flow isolated rat hearts. EPR oximetry with lithium phthalocyanine was used to measure myocardial pO~2~. Baseline myocardial pO~2~ (means ± SE) was 185 ± 13 mmHg (normoperfused) and 162 ± 14 mmHg (hypoperfused). Myocardial pO~2~ fell to <1 mmHg during no‐flow ischemia. After recovery from repetitive ischemia, myocardial pO~2~ and coronary resistance increased significantly in all hearts; oxygen consumption and left ventricle work decreased in normoperfused hearts, although not significantly compared with controls, and did not change significantly in hypoperfused hearts. Increased myocardial pO~2~ in the normoperfused group may be due to decreased oxygen consumption and/or increased local delivery, while increased myocardial pO~2~ in the hypoperfused hearts is due to increased local oxygen delivery.