The effects of cold acclimation on electrocardiogram parameters in five species of turtles.

The effects of thermal acclimation at 25 or 5 degrees C on electrical activity in the heart were investigated in Pseudemys scripta, Terrapene carolina, Chrysemys picta marginata, Chrysemys picta dorsalis, Chelydra serpentina, and Sternotherus odoratus. The durations of the QRS complex and P-R, R-T and R-R intervals were found to increase with decreasing body temperature in all animals tested. The amplitudes of the P and T waves and QRS complex were dependent upon both acclimation temperature and test temperature. Differences between acclimation groups in the change in QRS amplitudes between 20 and 0 degrees C were statistically significant for all species.