Congestive heart failure is a term describing a group of clinical signs that develop as a result of other cardiac diseases. As the name implies, equine congestive heart failure is generally an endpoint of disease, and it is considered rare in horses. There is little information available about congestive heart failure, but a study from North Carolina State University re-examined cases of the problem in an effort to define the most common signs, diagnostic findings, and prognosis.

Fourteen horses were diagnosed with congestive heart failure over the seven-year study period, which represented only 10% of all cardiac cases in horses. The most consistent clinical findings included heart murmur and rapid heart rate, which were evident in all 14 horses. Other signs included distension (enlargement) and even visible pulsation of the jugular veins, coughing, rapid breathing, and edema (swelling) along the ventral abdomen and lower extremities. Underlying cardiac diseases varied tremendously, as did the age of affected horses. Mitral valve insufficiency and regurgitation were identified as the most common causes.

During echocardiographic examination, 12 of the 14 horses were found to have enlarged hearts. Regardless of cause, signs of poor cardiac function, including weakness, exercise intolerance, collapse, etc., along with a consistently increased heart rate, were found to be highly suggestive of heart failure. Unfortunately, of the 12 horses for which follow-up information was available, all were either euthanized or died within a year of diagnosis. Therefore, congestive heart failure carries a grave prognosis in horses.

Davis, J.L.; Gardner, S.Y.; Schwabenton, B.; et al. Journal of the American Veterinary Medical Association, 220 (1), 1512-1515, 2002