Response of the Guinea Pig Heart to Hypothermia

Abstract

Electrocardiograms were obtained from guinea pigs acclimatized to 8°C and 22 °C respectively and then observed at 4°-5°C. No differences were recorded in cardiac responses to cold in guinea pigs from the two acclimatization temperatures. Heart rate decreased linearly with body temperature. Various durations on the ECG record varied non-linearly with temperature: y = a+b/(x-c), where y is duration, e.g. T wave, x is colonic temperature in °C, and a and b are constants, giving respectively the value of y when x is 0°C and the slope of the line relating body temperature to y. The Qi0 value of the heart rate varies with temperature.