Elevated body temperature during myocardial ischemia/reperfusion exacerbates necrosis and worsens no-reflow.
OBJECTIVE
The effects of an elevated body temperature on infarct size were tested in a rabbit model of ischemia/reperfusion.


METHODS
Before coronary artery occlusion, body temperature was raised from baseline at 38.6 +/- 0.1 degrees C to 40.3 +/- 0.2 degrees C in nine treated rabbits. Temperature in eight normothermic rabbits was 38.4 +/- 0.2 degrees C. Both groups received 30 min coronary occlusion and 3 h reperfusion.


RESULTS
In normothermic rabbits, 36 +/- 6% of the ischemic risk region became necrotic but in hyperthermic rabbits myocardial necrosis was significantly increased to 57 +/- 3% of the risk region (P < 0.005) despite similar risk regions and an equal degree of regional myocardial blood flow (RMBF) reduction during ischemia in both groups. Infarct size correlated positively with body temperature (r = 0.66, P < 0.004). RMBF was 43% lower during reperfusion in the previously ischemic areas of hyperthermic hearts compared with the control group (P < 0.04), suggesting worsened no-reflow.


CONCLUSIONS
Elevation in body temperature by even a few degrees can aggravate necrosis during acute myocardial infarction and worsens no-reflow.
Heart Institute of Good Samaritan Hospital and Department of Medicine, University of Southern California, Los Angeles, California 90017, USA. sharon.hale@attglobal.net
Sharon L
SL
Hale
Robert A
RA
Kloner
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004195:Disease Models, Animal; D005334:Fever / Q000150:complications* / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006352:Heart Ventricles / Q000473:pathology; D008297:Male; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000150:complications* / Q000503:physiopathology*; D015428:Myocardial Reperfusion Injury / Q000150:complications* / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis; D011817:Rabbits; D012039:Regional Blood Flow / Q000502:physiology*; D013223:Statistics as Topic