MSD Manual

Please confirm that you are a health care professional

honeypot link
Pet Owner Version

Heart Failure in Horses


Mark D. Kittleson

, DVM, PhD, DACVIM-Cardiology, Department of Medicine and Epidemiology, University of California, Davis

Reviewed/Revised Jul 2019 | Modified Oct 2022

Signs of Heart Failure in Horses

Signs associated with heart failure depend on the causes of the heart failure and the heart chamber that is affected. With left- congestive heart failure, signs are associated with a backup of pressure in the vessels delivering blood to the left ventricle. This causes fluid to accumulate within the lungs (called pulmonary edema). The most common signs are difficulty breathing, increased respiratory rate, poor performance, and tiring easily (especially with exercise or work). Horses may also cough.

Right-side congestive heart failure results in increased pressure in the vessels delivering blood to the right atrium and in the body’s veins and capillaries. This may cause fluid to build up under the skin on the underside of the chest and abdomen and in the limbs. Fluid can also accumulate in the abdomen (called ascites). Jugular distension and exaggerated pulses are also common.

Treatment of Heart Failure in Horses

It is important to treat heart failure in order to improve heart muscle performance, control arrhythmias and blood pressure, improve blood flow, and reduce the amount of blood filling the heart before contraction. All of these can further damage the heart and blood vessels if not controlled. It is also necessary to reduce the amount of fluid build-up in the body.

There are many types of drugs available for treating heart failure. The specific drugs, dosage, and frequency used will vary depending on the causes and severity of the heart failure and other factors. Your veterinarian is best able to determine the appropriate medications for your horse. All drugs prescribed by your veterinarian must be given as directed. Otherwise, they may not be effective and may even cause serious complications and harm.

Diuretics are usually prescribed to reduce fluid overload. Digitalis and digoxin, part of a group of drugs known as positive inotropes, may be used to help the heart muscle contract. ACE inhibitors (ACE stands for angiotensin-converting enzyme) and vasodilators can widen blood vessels and thus lower blood pressure.

For More Information

quiz link

Test your knowledge

Take a Quiz!