What is AV valve endocardiosis?
Chronic mitral valve or tricuspid valve endocardiosis is a disease in dogs characterized by progressive myxomatous degeneration of the atrio-ventricular (AV) valves. It is estimated that this disease accounts for 50% of canine cardiac disease. This disease process is also seen in humans, horses, and pigs. Mitral valve endocardiosis is seen in all breeds, but the prevalence of the disease varies greatly with small-to medium-size breeds most commonly affected. Progression of this disease begins with a small regurgitant fraction from the ventricle into the atrium that the atrium can easily accept and the forward stroke volume is maintained. As the disease progresses over time, the regurgitant fraction of the total left ventricular stroke volume increases. Forward stroke volume is maintained until a certain point when vascular, renal, and neurohormonal compensatory mechanisms are overwhelmed. The left ventricle then compensates by increasing the end diastolic volume (preload) and by increa
