How to Identify Horse Heart Murmurs

When a horse develops a heart murmur, the symptoms can be so mild that you may not notice. Usually, the veterinarian is the first person to realize that your horse has a heart murmur. Heart murmurs in horses usually indicate a valve abnormality. Murmurs are caused by either an obstruction of blood flow out of the heart or leakage of blood back into the heart. Heart murmurs are characterized by location, sound and occurrence during diastole, systole, or both. They are graded on a scale of 1 to 5 or 1 to 6 based on loudness. The most common heart murmur, called aortic insufficiency murmur, is caused by a leaky aortic valve. This murmur causes little overall effect on the health of the horse. In fact, research indicates that only 10 percent of horses with heart murmurs have reduced performance. A more serious murmur in horses is a mitral insufficiency murmur. What can you look for in your horse to identify a heart murmur?

Things You'll Need

  • Veterinarian
  • Stethoscope
  • Horse
  • Grooming supplies
  • Time spent with your horse
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Instructions

    • 1

      Schedule a complete physical for your horse each year. Typically, the veterinarian is going to see your horse at least annually to give him immunizations, so this is a good time for a physical as well.

    • 2

      Watch your horse for extreme exercise intolerance, which may include pulling up while working or even collapsing. This could be a sign of acute mitral valve rupture.

    • 3

      Experiencing tremors for no other reason could be a sign of acute mitral valve rupture. Some horses cough when they have a heart murmur. If there is profound cardiac failure, froth may come out of the nostrils as well, which is a manifestation of pulmonary edema.

    • 4

      Notice if your horse's heart is beating extremely fast, if she is breathing more rapidly than usual or if her gums have turned blue. These can be signs of acute mitral valve rupture. You should call your veterinarian for an evaluation.

    • 5

      Has your horse recently suffered from colic? Colic can be a sign of a heart murmur, and represent another reason to have your horse evaluated by the vet.

    • 6

      A decrease in appetite--accompanied by weight loss and lethargy for no other discernible reason--could be signs of a heart murmur caused by regurgitation across the mitral valve, an enlarged atrium and a decrease in myocardial contractility.

    • 7

      Groom your horse frequently and rub your hands over his neck. You may notice a generalized venous distention, as well as edema of the legs, or under the belly. These are signs of a heart murmur.

    • 8

      Have a professional evaluate the extent of the heart problem and the significance of the murmur by using diagnostic ultrasound, electrocardiogram (ECG) and echocardiogram (ECHO).