Influences of hypothermia, cold, and isolation stress on the severity of coronary artery ligation-induced arrhythmias in rats.
With a view to increasing the severity of the arrhythmias that arise following coronary artery ligation in anesthetized rats, the influences of exposure to lowered environmental temperature (LET) (21 to 13 degrees C) and isolation stress were examined. Housing rats singly for 48 hr, prior to the induction of arrhythmias, caused the most marked changes in the severity of the model; the incidence of ventricular fibrillation and mortality were increase from 43 to 90% and 9 to 60%, respectively. Exposure of multiply housed rats to LET for 48 hr also significantly increased mortality from fibrillation. A combination of LET plus isolation stress, however, did not further increase the severity of the arrhythmias following ligation. Acute hypothermia (body temperature reduced to 30 or 25 degrees C) did not significantly enhance the severity of the model.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D003080:Cold Temperature / Q000009:adverse effects*; D003331:Coronary Vessels; D004195:Disease Models, Animal; D007035:Hypothermia / Q000150:complications*; D008026:Ligation; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012934:Social Isolation