A veterinarian often diagnoses cardiovascular disease by reviewing the medical history and signs, conducting a physical examination, and interpreting the results of specific tests or imaging procedures. The physical examination includes using a stethoscope to listen to the sounds made by the horse's internal organs, especially the heart, lungs, and abdominal organs, x‑rays, electrocardiography (recording electrical activity of the heart), and echocardiography (a type of ultrasonography).

Most cardiovascular diseases can be diagnosed by physical examination and x‑rays. Electrocardiography is a specific test for diagnosis of arrhythmias. Echocardiography is excellent for confirming tentative diagnoses, for detecting heart tumors, or for detecting pericardial disease. Occasionally, more specialized tests such as cardiac catheterization (-using a thin flexible tube inserted and threaded through an artery into the heart) or nuclear studies (x-ray tests that include injection of radioactive isotopes) are necessary (see Heart and Blood Vessel Disorders of Dogs: Diagnosis of Cardiovascular Disease in Dogs).

General Signs of Cardiovascular Disease

Horses with heart disorders or defects may have a general loss of condition, become fatigued easily (particularly after exercise), have difficulty breathing or shortness of breath, and show signs of weakness (including fainting or collapse). In addition, excess fluid that has accumulated in the chest or abdominal area may indicate heart failure. Signs may show up only after exercise, but over time they may occur even when the horse is at rest.

Last full review/revision July 2011 by Davin Borde, DVM, DACVIM; Benjamin J. Darien, DVM, MS, DACVIM; Ase Risberg, VMD