Clinical case of tetralogy of fallot: a congenital heart defect in a dog

An 8-wk-old, female wire fox terrier weighing 1.5 kg was admitted to the Small Animal Clinic for an echocardiographic examination to rule out a congenital heart defect. Doppler echocardiography revealed tetralogy of Fallot. This heart defect is infrequently reported in animals (dogs, cats, horses). Research in veterinary medicine on congenital heart defects has shown a genetic predeposition to tetralogy of Fallot in Keeshounds and English bulldogs. Tetralogy of Fallot is a combined cardiac malformation which includes a ventricular septal defect, dextroposition of the aorta, pulmonic stenosis and right ventricular hypertrophy, which leads to a right to left cardiac shunt. Non-oxygenated blood is pumped to systemic circulation leading to hypoxia. A final diagnosis can be complete echocardiographic examination.