ABSTRACT
Background: Congenital cardiac diseases are a common cause of death in puppies. Tricuspid valve dysplasia is characterized by thickening and displacement of the leaflets of the tricuspid valve, agenesis of the valves, and incomplete separationof valve components. Papillary muscles may fuse and display shortened or absent chordae tendineae that contribute totricuspid regurgitation. Diagnostic features of tricuspid valve dysplasia include cardiomegaly with massive right atriumenlargement on thoracic radiography and tricuspid insufficiency on an ultrasound. We aimed to describe clinicopathological findings in a dog (Canis familiaris) with tricuspid dysplasia.Case: We aimed to describe tricuspid valve dysplasia in a dog referred for necropsy at the Anatomical Pathology Sector ofThe Rural Federal University of Rio de Janeiro, Brazil, with a clinical history of abdominal swelling, dyspnea, cyanosis,ascites, and prostration. Echocardiography and abdominal ultrasound revealed right ventricular enlargement, hepatomegaly,and splenomegaly. Examination of the heart showed prominent enlargement, thickening and dilation of the right chambers,thickening of the tricuspid leaflets, and moderately shortened chordae tendineae. The liver was enlarged, with a nutmegpattern, and foci of clotting and fibrin adhesions in the lateral right lobule.Discussion: Epidemiological, clinical, and pathological findings were consistent with tricuspid valve dysplasia. Althoughstructural abnormalities of the tricuspid and mitral valves are well known in fetuses and neonates, congenital and secondary tricuspid malformations are rare in dogs. The survival rate is associated with the severity of heart lesions. Tricuspidvalve dysplasia is mostly observed in large-breed...