Feline Hypertrophic Cardiomyopathy: Case Report and Challenges in Clinical Diagnosis

Hypertrophic cardiomyopathy (HCM) is the most common cardiac disease in cats, characterized by concentric thickening of the left ventricle, which can lead to arterial thromboembolism and sudden death. This report describes the case of a 17-year-old, 4.5 kg, spayed female Persian cat presented with sudden paralysis of the pelvic limbs. On physical examination, absence of femoral pulse, cold extremities, and systolic murmurs were observed. Initial blood counts were within normal limits but later evolved to a leukogram consistent with chronic stress. Abdominal ultrasonography revealed multiple hepatic and renal cysts, while echocardiography showed concentric hypertrophy, atrial enlargement, and the presence of a “smoke” signal. The diagnosis was thromboembolism secondary to HCM. Treatment included spironolactone, enoxaparin, and methadone, as well as amputation of the right pelvic limb due to necrosis. Despite therapeutic measures, the condition progressed with signs of recurrent thrombosis and a possible pulmonary neoplasm, ultimately leading to euthanasia. This case highlights the importance of early diagnosis and continuous monitoring in predisposed cats, as HCM has a progressive course, presents diagnostic challenges, and carries a guarded prognosis, with thromboembolism being one of the main causes of mortality.