Endocardial fibroelastosis and tricuspid valve insufficiency in a calf.

A 5-month-old Holstein heifer had clinical signs of tricuspid valve insufficiency and histopathologic evidence of endocardial fibroelastosis. The calf had a 3-week history of weight loss, abdominal distention, dyspnea, and decreased appetite. Physical examination revealed signs of right-sided heart failure, and a systolic murmur (II/VI) was heard best over the right heart base. Results of cardiac catheterization and echocardiography indicated tricuspid valve insufficiency and right-sided heart failure. The calf was euthanatized after not responding to treatment with penicillin, furosemide, and removal of fluid from the thorax and abdomen. Necropsy findings included multifocal areas of thickening and opacification of the endocardium of the left and right ventricles. Excessive elastic fibers, consistent with fibroelastosis, were seen by use of special stains applied to sections of endocardium.