What you see. The starting point for addressing any equine health related issue is your observation.


Pulse or Heart Beat Irregular, Arrhythmia


You listen to your horse's heart and hear an abnormal rhythm, or you feel an irregular pulse. An irregular heartbeat or pulse in an otherwise normal healthy horse is fairly common. Horses at rest often have an irregular rhythm. Commonly there is a dropped heart sound or a completely missing beat: Lub-Dub, Lub-Dub, Lub-dub, Lub..... pause....Lub-Dub, etc. Taken alone, this usually is not a serious problem.

However, heart disease, blood electrolyte abnormalities and other factors can also cause a variety of different irregular rhythms. Some of these can be an indication of life-threatening disease.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the horse's appetite and attitude are normal and you see nothing else wrong.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.
You also might be observing
Very Common
Less Common
more observations

your role


What To Do

Assess your horse's general health using the Whole Horse Exam (WHE) and pay special attention to your horse's mucous membrane color, pulse strength and regularity, and their general attitude. If you do not notice any other problem or abnormality, exercise your horse lightly and then listen again to their heart. Does the irregular rhythm disappear with the increase in heart rate? If the horse seems normal otherwise, talk to your vet about your findings as soon as it is convenient. On the other hand, if the horse shows any other signs of illness or disease, contact your vet immediately.

your vet's role

Your vet will help you determine whether your horse has a physiologic arrhythmia (within normal range), or something pathologic and potentially serious.
Questions Your Vet Might Ask:
  • Does your horse seem normal otherwise?
  • What, specifically are you noticing? Describe the problem.
  • Does the horse's appetite and attitude seem normal?
  • What are the results of the Whole Horse Exam (WHE)?
  • Does the problem go away with exercise?
  • Have you noticed changes in exercise tolerance, i.e. breathing hard when ridden or taking a longer t
  • Does your horse still perform well and recover quickly when ridden?
  • When did you first notice this problem?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
more diagnoses

Treatments Your Vet May Recommend

A way to resolve the condition or diagnosis. Resolving the underlying cause or treating the signs of disease (symptomatic treatment)

Very Common
more treatments

Author: Doug Thal DVM Dipl. ABVP