Heart Valve Infection (Infective Endocarditis) in Dogs

By PetMD Editorial on Oct. 20, 2009

Infective Endocarditis in Dogs

Infective endocarditis is a medical condition in which the inner lining of heart has become inflamed in response to an infection in the body. Generalized infections in the body may invade the inner lining of heart, as well as the valves of the heart. This type of infective endocarditis can occur in response to any infection of the body.

Endocarditis is more common in middle-sized to large breed dogs, with most between the ages of four and six. Males are generally at higher risk than females. If the underlying disease if not treated in time, complications can lead to heart failure and death.

Symptoms and Types

A variable set of symptoms may be present in patient depending upon the nature and site of infection, complications and extent of affects on heart. The following symptoms may be present in an affected dog:

  • Fever
  • Cough
  • Bluish discoloration of skin
  • Weakness
  • Lethargy
  • Anorexia
  • Weight loss
  • Reluctance to move
  • Body aches and pains
  • Symptoms related to heart problems
  • Difficult breathing
  • Intermittent lameness
  • Gastrointestinal disturbances


  • Bacterial Infections
  • Previous major surgery


You will need to give your veterinarian a complete background history of your dog’s health, including information about the onset of symptoms, any illnesses or injuries your dog has experienced, any surgical procedures, and the duration and frequency of symptoms that have been apparent.

Your veterinarian will perform a complete physical examination, including basic laboratory testing: a complete blood count (CBC) test, biochemistry profile, and urinalysis. The results of these tests may reveal information related to the underlying infection, and may point to the organs being affected.

Blood cultures will help to determine the causative agent involved in the infection and will also allow your veterinarian to determine the most suitable antibiotics for treatment of the underlying infection. A visual examination of the heart, using radiographic (i.e., X-ray) studies can help your veterinarian to determine the extent of heart involvement, and echocardiography, which uses ultrasound to image the inner organs, is an excellent tool for a detailed evaluation of the heart's functioning ability. Your veterinarian will also need to measure the electrical activity of the heart, which is done using an electrocardiogram (ECG) to record the heart's movement and impulses.


This is serious health problem for animals, and your dog will most likely require hospitalization for intensive care and treatment. Fluid therapy and antibiotic therapy will be given to restore and maintain body fluid levels and to control the infection, respectively.

Patients with valve involvement generally are not given a good prognosis. However, this is often dependent upon the stage of the infection and the functionality of the heart. Treatment is normally given over the course of 12 weeks, during which time your veterinarian will take multiple blood samples at regular intervals to measure how much of the infection, if any, is still present. After antibiotic therapy has stopped, blood samples will be taken to confirm that the infection has been resolved.

Living and Management

If your dog’s heart problem was mild, it will usually respond well to treatment. If the endocarditis was diagnosed in time, and aggressive treatment was employed along with a detailed follow up, the chances of a full recovery are also greatly enhanced.

You may need to take your dog to the veterinarian for weekly follow-up examinations, and to determine overall progress. Your veterinarian may also suggest a special diet for your dog to improve cardiovascular functioning and organ health. Treatment will be directed towards treating the underlying infection as well as the heart problems that have resulted from such infections. In cases where a diagnosis was not made early on, and the disease has had an opportunity to advance, the overall prognosis may be very poor due to further complications that are common in affected dogs. In such a case, your veterinarian will advise you on alternative plans. 

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