What is Heart Disease?
Heart disease in horses is a very serious condition. If you suspect that your horse may be having symptoms of heart disease, it is imperative that he is seen by a veterinarian. Early diagnoses and treatment of heart disease can help the prognosis for the horse. Heart disease, if left untreated, will be fatal.
Heart disease in horses happens when there is a malfunction in the heart or its surrounding blood vessels, which then causes the heart not to work normally. The heart is a vital organ that pumps oxygenated blood and nutrient throughout the body, including all of the other organs.
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Symptoms of Heart Disease in Horses
Symptoms of heart disease in horses may include one or more of the following:
- Tires easily
- Decrease in performance
- Exercise intolerance
- Labored breathing
- Dyspnea (shortness of breath)
- Abnormal gait
- Abdominal edema
- Heart murmurs
- Weak pulse
Causes of Heart Disease in Horses
- Septal defect is the most common congenital heart abnormality in horse; this is a hole in the wall which separates the ventricles
- Patent ductus arteriosus is the blood vessel that connects the pulmonary artery to the aorta, in foals inside the placenta; the patent ductus artery should normally close after birth, once the foal begins to use his lungs.
- Tricuspid dysplasia is the abnormal formation of the tricuspid valve in the heart.
Equine Viral Infections
- Infectious anemia
- Influenza virus
- Viral arteritis
- Streptococcus equi
- Rhodococcus equi
- Disruption of electrical signals
- Medication side effect
Diagnosis of Heart Disease in Horses
A history of recent injury, diet, recent vaccinations, and onset of symptoms will be discussed with the veterinarian. The physical examination may point to issues with the heart.
- Heart and lung evaluation with a stethoscope
- Blood pressure
- Rectal exam
- Mucous membrane color
- Palpitation of the limbs, muscles and lymph nodes
Diagnostic tests may include:
- Complete blood count - Checks the count of platelets, red and white blood cells
- Serum chemistry panel - This blood test checks on organ functions (kidneys, liver, blood protein and electrolytes)
- Chest x-rays - Can show heart enlargement or accumulation of fluids
- Echocardiography - Can take two and three dimensional images of the heart and can also monitor how the heart is pumping, evaluate the flow of the blood, and detect tissue damage
- Electrocardiogram (EKG) – Checks electrical activity in the heart
- Electrocardiography – Records the electrical activity of the heart
- Exercise testing – Electrocardiogram or electrocardiograph are performed after the horse has exercised
- The horse may have to be sedated for some of these diagnostic tests
Treatment of Heart Disease in Horses
The treatment of heart disease in horses depend on the diagnosed disease. Some heart disease will need surgery to repair the damage. Heart surgery may include open heart surgery or the use of a catheter.
Common heart medications used are lidocaine, enalapril, magnesium sulfate, digoxin and furosemide. The use of these medications can help slow down the disease and may alleviate some of the symptoms. If the horse has bacterial pericarditis, antibiotics will be prescribed.
If the diagnostics showed fluid around the heart, the veterinarian may suggest a diuretic such as furosemide to reduce the fluid. If the fluid remains, he may recommend aspirating the fluid to help the heart to pump normally. Anti-inflammatory and corticosteroids may be recommended if there is inflammation of the heart muscle.
Thrombophlebitis, inflammation of the jugular vein, is usually treated with anticoagulants (blood thinners) such as heparin. The veterinarian may also recommend, gently applying the topical DMSO ointment to the inflamed jugular vein
Balloon-dilation is a procedure that may be recommended if the valves are narrow, it can help widen heart valves. Patients with heart disease affecting the valves may also benefit from low levels of exercise.
Recovery of Heart Disease in Horses
Follow-up visits will be necessary to monitor the horse. Some heart medications may have side effects such as colic, edema or depression. Call the veterinarian if you see any signs of side effects.
Patients that underwent surgery will be given post-surgery instructions by the equine surgeon. Your horse may be prescribed pain management medications and antibiotics. Sutures will need to be removed by the veterinarian. The horse should have limited exercise.
Diagnostic tests will need to be re-taken, which may include additional blood work, EKG, echocardiography, and x-rays. These tests will determine how the horse is responding to the treatment plan. Prognosis is dependent on the stage of the illness and severity of the disease. Diagnoses and treatment of a heart disease in the early stages leads to a much better prognosis. In some cases horses may need to be on lifelong medication treatments.