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Effect of repetitive ischemia on myocardial oxygen tension in isolated perfused and hypoperfiised rat hearts
Author(s) -
Friedman Bruce J.,
Grinberg Oleg Y.,
Isaacs Kimberly A.,
Ruuge Enno K.,
Swartz Harold M.
Publication year - 1996
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910350213
Subject(s) - ischemia , oxygen tension , cardiology , oxygen , myocardial ischemia , medicine , tension (geology) , chemistry , materials science , organic chemistry , metallurgy , ultimate tensile strength
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.