Equis ISSN 2398-2977

Heart: endocarditis

Synonym(s): Bacterial endocarditis, valvular endocarditis, vegetative endocarditis

Contributor(s): Karen Blissit, Karen Blissitt, Christopher Brown, Lesley Young


  • Inflammatory changes to valvular endocardium.
  • Cause: bacterial.
  • Signs: vary depending upon underlying etiology: lethargy, recurreent pyrexia, malaise, sudden onset cardiac murmurs, congestive heart failure.
  • Diagnosis: hematology - serial positive blood culture in cases of bacterial endocarditis; echocardiography to confirm irregular valve thickening (vegetations) and valvular regurgitation.
  • Treatment: early and agressive treatment necessary. Long-term antibiotics for bacterial endocarditis.
  • Prognosis: poor - in many cases valvular damage is too severe to allow successful return to athletic performance, even if a bacteriological cure can be achieved.
  • There may be involvement of other organs (joints, kidneys) if there is shedding of septic emboli.



Bacterial endocarditis


  • Pre-existing valvular damage may predispose to bacterial endocarditis.


  • Bacteria invade valve surface facing the flow of blood.
  • Bacteria   →   invade normal valves   →   ulceration   →   exposes underlying collagen.
  • Platelets attach to ulceration   →   thrombus formation   →   organization   →   shortening and deformation of the valves   →   valvular regurgitation; more rarely stenosis.


  • Bacteremia   →   invade valves previously damaged.
  • Autoimmune complexes may affect other organ systems.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Froehlich W, Wlaschitz S, Reidelberger K & Reef V B (2006) Tricuspid valve endocarditis in a horse with ventricular septal defect. Equine Vet Educ 18 (4), 172-176 VetMedResource.
  • Verdegaal D J M M et al (2006) A right-sided bacterial endocarditis of dental origin in a horse. Equine Vet Educ 18 (4), 191-195 VetMedResource.
  • Verdegaal E J M M & Sloet van Oldruitenborch-Oosterbaan M M (2006) Endocarditis in the horse. Equine Vet Educ 18 (4), 196-198 VetMedResource.
  • Ramzan P H L (2000) Vegetative bacterial endocarditis associated with septic tenosynovitis of the digital sheath in a Thoroughbred racehorse. Equine Vet Educ 12 (3), 120-123 VetMedResource.
  • Maxson A D & Reef V B (1997) Bacterial endocarditis in horses: ten cases (1984-1995). Equine Vet J 29 (5), 394-399 PubMed.
  • Travers C W & van den Berg J S (1995) Pseudomonas spp. associated vegetative endocarditis in two horses. J S Afr Vet Asoc 66 (3), 172-176 PubMed.
  • Dwart S, Brown C, Derksen F & Kufuor-Mensa E (1992) Serratia marcescens endocarditis in a horse. JAVMA 200 (7), 961-963 PubMed.
  • Nilsfors L, Lombard C W, Weckner D & Kvart C (1991) Diagnosis of pulmonary valve endocarditis in a horse. Equine Vet J 23, 479-482 PubMed.
  • Hillyer M H, Mair T S & Holmes J R (1990) Treatment of bacterial endocarditis in a shire mare. Equine Vet Educ 2, 5-7 VetMedResource.
  • Dedrick P, Reef V B, Sweeney R W & Morris D D (1988) Treatment of bacterial endocarditis in a horse. JAVMA 193 (3), 339-342 PubMed.
  • Buergelt C D, Cooley A J, Hines S A & Pipers F S (1985) Endocarditis in six horses. Vet Pathol 22 (4), 333-337 PubMed.
  • McCormick B S, Peet R L & Downes K (1985) Erysipelothrix rhusiopathiae vegetative endocarditis in a horse. Aust Vet J 62 (11), 392 PubMed.
  • Bonagura J D & Pipers F S (1983) Echocardiographic features of aortic valve endocarditis in a dog, a cow and a horse. JAVMA 182 (6), 595-599 PubMed.