Heart Valve Infection (Infective Endocarditis) in Cats

By PetMD Editorial on Oct. 20, 2009

Infective Endocarditis in Cats


Inflammation of the inner lining of the heart is medically referred to as endocarditis. Infective endocarditis can occur in response to any infection of the body. Generalized infections in the body may invade the inner lining of heart, as well as the valves of the heart. If the underlying disease if not treated in time, complications can lead to heart failure and death. This condition is rarely seen in cats.

Symptoms and Types

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 cat:

  • Fever
  • Cough
  • Bluish discoloration of the 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 for your cat, including information about the onset of symptoms, any illnesses or injuries your cat 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 a serious health problem and your cat will most likely require immediate hospitalization for intensive care and treatment. Fluid therapy and antibiotic therapy will be started to maintain body fluid level and to control the infection, respectively.

Patients with valve involvement generally do not have good prognosis. Treatment is usually continued for 12 weeks. During that 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 cat'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 detailed follow up, the chances of a full recovery are greatly enhanced.

You may need to take your cat to the veterinarian for weekly follow-up examinations, and to determine overall progress. Your veterinarian may also suggest a special diet for your cat 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 cats. In such a case, you will need to consult with your veterinarian on alternative plans.

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