Canine infective endocarditis

Abstract

Canine infective endocarditis is defined as an infection of the endocardium, commonly involving one or more heart valves and leading to proliferative (vegetative) or erosive lesions. Prerequisites for development of infective endocarditis include endocardial damage, formation of a sterile vegetative lesion or coagulum, presence of bacteraemia and microorganism adherence to the coagulum. Predisposing factors include any that may facilitate meeting the prerequisites, including congenital heart disease, extra-oral infections and immunosuppression, amongst others. Large, male, middle-aged and purebred dogs may be overrepresented, in particular Labrador Retrievers, Golden Retrievers, Boxers and German Shepherd Dogs. Typically caused by bacteria, the most common isolates include Streptococcus spp., Staphylococcus spp., Gram-negative rods (particularly Escherichia coli) and Bartonella spp. Blood culture can have low sensitivity, with up to 70% of cultures being negative. Bartonella spp. are increasingly being recognised as a cause of culture-negative aortic infective endocarditis. The preferred method of diagnosis in vivo is echocardiography, with a reported sensitivity of 87.5%. The prognosis is guarded despite appropriate treatment, and some negative prognostic factors have been identified.