ANALYSIS OF TEMPERATURE CHARACTERISTIC OF SYSTOLE IN HIBERNATOR WITH ULTRASONIC TOMOGRAPHY

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In this study, I examined temperature characteristic of cardiac function with ultrasonic tomograph by B- and M-modes under a course of hypothermia at 8ﾟC caused by acute cold exposure hibernator (Syrian hamster). I compared it with experimental findings of non-hibernator (Wistar rat) as control group.In electrocardiography (ECG), complete atrioventricular block was observed at abdominal temperature (Tab) of 19ﾟC with non-hibernator, but atrio-ventricular block of the first stage that P-Q interval got longer at 10ﾟC was recognized in hibernator. Furthermore, Tab was 18.11 <plus-minus> 0.83ﾟC in non-hibernator, then ECG disappeared. But the phenomenon wasn't observed to depressed Tab of 7.22 <plus-minus> 0.31ﾟC in hibernator. Movement of myocardium of left ventricle became slow when became less than 21.8ﾟC with non-hibernator in ultrasonic tomography of heart stroke. Speed of mitral valve also observed slowly, so degradation of cardiac output was suggested. On the other hand, similar development was found by 9.8ﾟC in hibernator. As examination subject after now, it couldn't measure a clear ultrasonic tomography by shivering of cold exposure early stIn non-hibernation, cardiac function of hibernator was maintained under hypothermia, the significant cold tolerance was provided as well as in hibernation.