Groundhogs spend the winter hibernating in a specially dug hibernation burrow, their breathing and heartbeats slowed to a snail's pace, their body temperatures not too far above freezing.
If slow heartbeats (bradycardias) don't have a cause that can be corrected - such as low thyroid hormone levels or a drug side effect - doctors often treat them with a pacemaker.
A treatment for nausea and vomiting caused irregular heartbeats in humans.
This instrument monitors the patient's heartbeats.