Effect of temperature on myocardial infarction in swine.
Body core temperature in the normothermic range alters infarct size in rabbits. Moreover, temperature may modulate the protection by adenosine during a coronary artery occlusion. We investigated the effect of core temperature within the normothermic range (35-39 degrees C) on myocardial infarct size produced by a 45-min coronary occlusion in open-chest swine (n = 10), and we determined whether adenosine blockade with 8-phenyltheophylline and adenosine deaminase increased infarct size in the normothermic range (n = 9). After 4 h of reperfusion the area at risk and infarct size were determined with Evans blue dye and triphenyltetrazolium chloride. Infarct size strongly correlated with temperature (r2 = 0.71, P = 0.0001) so that at 35 degrees C no infarction occurred and with each 1 degree C increase in temperature 20% of the area at risk became infarcted. In contrast, neither the low levels of collateral flow (0.03 +/- 0.01 ml.min-1.g-1) nor the rate-pressure product correlated with infarct size. In the normothermic range, adenosine blockade had no effect on infarct size. The data demonstrate that temperature can exert a profound effect on infarct size but fail to demonstrate a protective effect on endogenous adenosine at normothermic temperatures. Our findings emphasize the need for stringent control of core temperature during investigation of interventions aimed at reducing infarct size.
Duncker
D J
DJ
Department of Medicine, University of Minnesota Medical School, Minneapolis 55455, USA.
Klassen
C L
CL
Ishibashi
Y
Y
Herrlinger
S H
SH
Pavek
T J
TJ
Bache
R J
RJ
D000241:Adenosine / Q000037:antagonists & inhibitors; D000243:Adenosine Deaminase / Q000494:pharmacology; D000818:Animals; D001831:Body Temperature; D003326:Coronary Circulation; D005260:Female; D006321:Heart / Q000503:physiopathology; D006439:Hemodynamics; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology
D013806:Theophylline; C028322:8-phenyltheophylline; D000243:Adenosine Deaminase; D000241:Adenosine