Firstly, check the detection settings for your chosen Heart Rate calculation to make sure each beat is being correctly identified. If these are set correctly, your research animal may be over-anesthetized and/or the body temperature may have dropped below normal physiologic level (37°C).
Check the anesthesia concentration and dosage. Perform the surgeries on a temperature-controlled blanket or heated operating table. If temperature-regulating equipment is being used, check the functionality of the temperature probe and temperature control hardware.
For further technical assistance with this or any other issue, please contact ADInstruments Technical Support by clicking HERE