Diagnosis of Cardiovascular Disease in Dogs
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 dog’s internal organs, especially the heart, lungs, and abdominal organs, and examining parts of the body by feeling with hands and fingers to distinguish between solid and fluid-filled swellings. Imaging techniques include 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 specific 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. Heartworm disease is diagnosed best by performing a blood test to detect the presence of female heartworms.
Many heart disorders are more common in certain breeds. For example, mitral regurgitation is more common in Cavalier King Charles Spaniels and in older, male Cocker Spaniels. Older Miniature Schnauzers may develop specific types of arrhythmias, and tetralogy of Fallot is more common in young Wirehaired Fox Terriers. Knowledge of these and other breed associations with heart disease can often help your veterinarian make a diagnosis.
Dogs showing signs of heart disease may have a history of exercise intolerance, weakness, coughing, difficulty breathing, increased breathing rate, abdominal swelling (caused by fluid pooling in the abdomen), loss of consciousness due to lack of blood flow to the brain (fainting), a bluish tinge to skin and membranes due to a lack of oxygen in the blood, or loss of appetite and weight. More rarely, swelling of the legs, jaundice (yellowing of the eyes, skin, or membranes), or coughing up blood or bloody mucous may be noted.