Felis ISSN 2398-2950


Synonym(s): Bacterial endocarditis Valvular endocarditis Infective endocarditis Verrucous endocarditis

Contributor(s): Phil Fox, Philip K Nicholls, Simon Swift


  • Rare.
  • Cause: bacterial infection of the valves of the heart, usually mitral or aortic.
  • Results in valvular incompetence with vegetations or more rarely stenosis.
  • Signs: septicemia, infective thromboembolism or acute heart failure.
  • Diagnosis: blood culture (not always positive), ultrasonography and clinical signs.
  • Treatment: combinations of bacteriocidal antibiotics for a prolonged period.
  • Prognosis: generally poor.



  • Possible relationship to congenital disease Congenital heart disease: overview such as subaortic stenosis Heart: aortic stenosis.
  • Such diseases increase risk of trauma to the valves and hence allow adhesion of bacteria.
  • However, in most cases the valves are normal.
  • There is no relationship to mitral valve endocardiosis.

Predisposing factors


  • Immunocompromized cats or those with congenital defects are likely to be at increased risk.


  • Bacteremia is very common following surgery or any procedure involving trauma to mucosal surfaces, but usually involves different bacteria to those involved in endocarditis.
  • Bacteria involved in endocarditis must also adhere to the valves possibly at a site of pre-existing damage such as a platelet thrombus to cause the disease.
  • Bacteremia is common but endocarditis is rare.
  • Under unknown circumstances, bacteria adhere to endocardial surfaces of the mitral or aortic valves.
  • Streptococci  Streptococcus sppStaphylococci  Staphylococcus sppPseudomonas spp   Pseudomonas sppE. coli  Escherichia coli  and E. rhusiopathiae are the bacteria most frequently involved.
  • Serum bacteriocidal activity is also important as resistant isolates have been shown to cause endocarditis.
  • Antibodies seem to be protective as they either stop adhesion or clear the bacteremia.
  • The aortic valve is most commonly affected, followed by the mitral valve.
  • The tricuspid valve is rarely involved and the pulmonic valve almost never.
  • The infection may cause valvular incompetence either by destroying the valve or by the production of vegetations on the valve.
  • Rarely valvular stenosis is produced.
  • Pieces of the vegetations may break off and embolize causing signs attributable to infarction or infection.
  • Signs vary depending on the area affected.
  • As a result of the chronic infection, immune-complex disease may be seen.
  • Severe aortic regurgitation is poorly tolerated and may cause acute left heart failure and death within a short time.
  • Endocarditis is reported as a differential diagnosis of an audible diastolic murmur.
  • In addition, it should be considered if there is pulmonary edema and minimal signs of heart enlargement.
  • Rarely the infection may involve the myocardium with vegetations on the mural endocardium.


  • Usually presented within 7 days.
  • If untreated rapidly progresses.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Malik R, Barrs V R, Church D B et al (1999) Vegetative endocarditis in six cats. J Feline Med Surg (2), 171-80 PubMed.
  • De Jonghe S, Ducatelle R, Devriese L A et al (1998) Verrucous endocarditis due to Escherichia coli in a Persian cat. Vet Rec 143 (11), 305-307 PubMed.
  • Yamaguchi R A, Pipers F S & Gamble D A (1983) Echocardiographic evaluation of a cat with bacterial vegetative endocarditis. JAVMA 183 (1), 118-120 PubMed.

Other sources of information

  • Caney S M A, Wotton P R et al (1997) Valvular endocarditis in four cats. Proceeding of ACVIM Lake Buena Vista, Florida pp 689.
  • Goodwin J K & Miller M W (1997) Infective endocarditis. In:Consultations in Feline Internal Medicine.Ed. J R August, W B Saunders. pp 273-278.
  • Thomas W P (1992) Update: infective endocarditis. In:Kirk's Current Veterinary Therapy XI.Ed R W Kirk & J D Bonagura, W B Saunders. pp 752-755.
  • Calvert C A (1988) Endocarditis and bacteraemia. In:Canine and Feline Cardiology.Ed P R Fox, Churchill Livingstone, pp 419-434.
  • Hawe R S (1980) Bacterial endocarditis, a review. In:Pet Practice. pp 1569-1579.