Heart failure is one of the most serious ailments that a dog can have. The early signs of heart disease often mimic those of other medical disorders. Dogs with an intermittent cough, labored breathing and an elevated heart rate, dogs that tire easily, have a pot-bellied appearance and are losing weight should be evaluated for heart disease. The veterinarian assessing a dog with those symptoms will take a thorough history from its owner about the dog’s vaccination status and onset of its symptoms, and will then perform a thorough physical examination, including carefully listening to the heart and lungs using a stethoscope. The doctor probably will recommend taking blood and urine samples for routine laboratory evaluation of the function of the dog’s vital organs, including a complete blood count, serum chemistry profile and urinalysis.
More advanced diagnostic procedures are necessary to accurately confirm a diagnosis of heart failure. One of the first things that a veterinarian may suggest is to take chest X-rays (thoracic radiographs). Radiographic images are the best way to identify an enlarged heart, such as that associated with dilated cardiomyopathy in larger breeds. Other tools include echocardiography, which lets the veterinarian assess the position and motion of the heart walls, valves and chambers by an echo obtained from beams of ultrasonic waves directed through the chest wall. This basically is an ultrasound of the heart. Electrocardiography can also be used to graphically record the electrical currents generated by the heart, as a means of assessing the strength and health of the entire heart musculature. Use of these techniques, together with through auscultation of the heart and lungs through a stethoscope, should enable the veterinarian to diagnose the dog’s condition. If heartworms are prevalent in the area where the dog lives, a blood test for the presence of heartworm antigen may be advisable.