EN
The case of a 12-year-old boxer dog, with an infiltrating tumour in cardiac base and dilated cardiomyopathy was described. Morphological and biochemical examinations of the blood, ECG, and USG of the heart were performed. In the resting ECG record, atrial fibrillation was detected with rapid action of ventricles. Echocardiography demonstrated distension of all cardiac cavities and a decreased contractility of the left ventricular myocardium. Despite intense treatment, the condition of the dog deteriorated: anaemia and renal insufficiency appeared and asphyxia intensified. At the owners' request, the dog was subjected to euthanasia. On autopsy, a tumour in the cardiac base was detected, which infiltrated the left atrial wall. Histopathology and immunohistochemistry permitted to diagnose neoplastic hypertrophy of chemodectoma type.