The phrase "abnormal rhythm" refers to a situation where the regular or normal pattern of a person's heartbeat is disrupted, and their heart beats too fast, too slow, or in an irregular manner. Full definition
This is because the size of our hearts is large enough to allow such abnormal rhythms to develop (we also see this in horses, which have large hearts). (vin.com)
Oral medications given at home may treat some of the common abnormal rhythms. (texvetpets.org)
Certain abnormal rhythms and heart rates can be dangerous to animals undergoing anesthesia. (abcvet.com)