The relationship between global myocardial ischemia, left ventricular function, myocardial redox state, and high energy phosphate profile. A phosphorous-31 nuclear magnetic resonance study.
The onset of global myocardial ischemia was related to mechanical function (intraventricular pressure), cellular redox state (NADH fluorophotography), and high energy profile (phosphorous-31 nuclear magnetic resonance). Ten rabbit hearts were excised and perfused on a modified Langendorff apparatus (37 degrees C; pO2 480 Torr). Developed pressure and positive and negative dp/dt were determined at control, 1-10, 15, 30, 45, and 60 sec of acute global ischemia. NADH fluorophotographs were taken at control, 1-10, 15, 20, 30, 60 sec, and 5, 10, and 30 min. P-31 NMR spectra in 14 guinea pig hearts under identical conditions were obtained at control, 1, 5, 10, 20, 40, and 60 min of acute global ischemia. LV contractility diminished within 1 sec (P less than 0.01) of ischemia and dropped to less than 35% of control by 1 min. Reduction of mitochondria was detected by epicardial NADH fluorophotography at 2 sec of ischemia. Cellular pH diminished 0.3 pH units by 5 min. Adenosine triphosphate (ATP) concentration remained at control levels while phosphocreatine (PCr) dropped to 63 +/- 8.5% of control by 1 min of ischemia.


CONCLUSIONS
After the onset of global ischemia (1) mitochondrial electron transport ceases by 2 sec; (2) acidosis develops immediately; (3) LV contractility diminishes by 1 sec; (4) ATP concentration appears to be buffered by PCr, and is dissociated from myocardial function.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003327:Coronary Disease / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology*; D009682:Magnetic Resonance Spectroscopy; D009200:Myocardial Contraction; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010710:Phosphates / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D011817:Rabbits
D010710:Phosphates; D010725:Phosphocreatine; D009243:NAD; D000255:Adenosine Triphosphate