Congestive heart failure in a horse is a relatively uncommon condition. Technically, heart failure refers to the inability of the heart to circulate enough blood to meet the horse's metabolic nutrient requirements. Signs and symptoms of heart failure often don't appear until the disease is quite advanced. As in other species, older horses are most often affected.
Signs of Congestive Heart Failure
Horses eventually diagnosed with congestive heart failure usually have other cardiac issues. Quick, shallow breathing, coughing, rapid heart rate and fluid accumulation resulting in swelling in the lower legs and the abdomen are typical indications of congestive heart failure. More subtle symptoms include exercise intolerance and general weakness. Some horses may show symptoms only after some exercise, even if it's not strenuous. In the latter stages of the disease, the affected horse shows symptoms even while resting. If your vet conducts an echocardiogram of your horse's heart in a clinical setting, it's likely the organ is enlarged.
Treating Congestive Heart Failure
If you've known a person or had a pet suffering from congestive heart failure, you'll likely recognize some of the medications used in treating the disease in equines -- albeit in larger doses. Diuretics help get rid of the edema, or accumulated fluid. Angiotensin-converting enzyme, or ACE, inhibitors lower blood pressure by widening the horse's blood vessels. Other common medications include digoxin and digitalis, used to aid heart muscle contraction.
Unfortunately, the prognosis for a horse diagnosed with congestive heart failure isn't good. Most horses will succumb within a year of diagnosis or the owner will choose to euthanize the animal.