Heart Disease in Pets

What is heart disease?

Heart disease in pets can have many origins. It can be caused by changes in the heart’s muscular walls, defects of the valves that separate the chambers of the heart, or narrowing of the vessels leaving the heart. As with humans, heart abnormalities can exist at birth or can develop late in life. Particularly for pets, heartworm is a major contributing factor.

The heart is a four-chambered muscular organ that functions to pump blood around the body. Heart failure occurs when the heart fails to pump enough blood to meet the body’s demands. This causes changes in the body as it tries to support a faltering system. These changes include increased blood pressure, increased heart rate, and fluid retention.
When the heart is unable to function correctly, there is a build-up of fluid pressure within the circulatory system. This can cause leakage of fluid into the chest or abdomen and is responsible for many of the clinical signs seen with heart disease.

Clinical signs of heart disease:

  • coughing
  • difficulty breathing
  • engorgement of veins (visible in the jugular vein in the neck)
  • swollen abdomen (fluid in the abdominal cavity)
  • enlarged liver
  • weight loss
  • decreased exercise tolerance – the dog tires easily
  • pale or blueish mucous membranes
  • cool extremities (toes, tips of ears etc)
  • fluid swelling of lower limbs

If you suspect your pet is suffering from heart disease, have them examined by your veterinarian.

Diagnosing heart disease

Diagnosis of heart disease begins with a thorough physical examination. Listening to the patient’s chest with a stethoscope can allow the veterinarian to identify any abnormal heart sounds, rhythms or lung sounds. If an abnormality is suspected, the next step is to X-ray the chest. Chest X-rays show the size and shape of the heart, any blood vessel enlargement within the chest, and any changes in the lungs.

Ultrasound of the heart (also called ‘echocardiography’) is a technique that is used to see the size of the heart chambers and the degree of contraction of the heart. More advanced ultrasound machines can even show the direction of blood flow through the heart.

An ECG (electrocardiogram) is another way to investigate heart disease. This device records the electrical impulses across the heart as nerves fire to stimulate the heart to beat. ECG’s are useful to determine any changes in the heart’s rhythm and can give an indication of changes of heart chamber size.

Other tests such as blood and urine tests can help determine changes caused by this disease, and are often recommended before therapy for heart disease is started.  Many different therapies for heart disease are available depending on the type and severity of the disorder. Most pets with mild heart disease respond well to therapy and can have an extended lifespan with treatment.

Many heart conditions are progressive, which is why early diagnosis is crucial. Therapy for heart disease is lifelong and requires regular check-ups to assess development.