Tetralogia de Fallot em cães: relato de dois casos

Abstract

Tetralogy of Fallot consists of a set of congenital cardiac malformations, including a ventricular septal defect, dextroposition of the aorta, pulmonary stenosis, and concentric right ventricular hypertrophy. The disease follows an autosomal recessive inheritance pattern and shows a predisposition in certain breeds, such as the French Bulldog. Clinical signs include cyanosis, erythrocytosis, exercise intolerance, syncope, and other manifestations that significantly affect the quality of life of affected animals.This study describes two cases of Tetralogy of Fallot in dogs seen at the Veterinary Hospital of the Federal University of Minas Gerais, highlighting variations in clinical presentations. In the first case, a 14-month-old female French Bulldog weighing 7.3 kg presented with complaints of exercise intolerance, syncope, and cyanosis. In the second case, an 11-month-old male French Bulldog weighing 8.25 kg had identical complaints. Both cases showed erythrocytosis in the complete blood count and right bundle branch block on the electrocardiogram, but the echocardiographic examination was crucial for confirming the diagnosis of Tetralogy of Fallot, as it allowed visualization of the malformations. Both dogs received the treatment recommended in the literature; however, the outcomes differed. The first case resulted in death shortly after diagnosis, while the second case showed improvement in clinical signs and quality of life up to the time of writing this report. It was observed that the progression of the disease is directly related to the severity of the cardiac anomalies present. Therapeutic management involves both supportive treatment and pharmacological and surgical interventions, with palliative procedures being the most commonly used.