A five-month-old female pomeranian dog (weighing 0.95 kg) with a history of cyanosis, exercise intolerance, and delayed growth presented to Veterinary Teaching Hospital, Gyeongsang National University. Findings on diagnostic imaging studies showed a dextropositioned and over-riding aorta, pulmonic stenosis, ventricular septal defect, right ventricular hypertrophy, and atrial septal defect. Based on the diagnostic findings, the dog was diagnosed as a case of tetralogy of Fallot with atrial septal defect (pentalogy of Fallot).

Four small breed dogs presented with various clinical signs, including seizures. Dual-phase computed tomography (CT) angiography of the abdominal region showed early enhancement of the venous system during the arterial phase. This finding is considered a classic indication of hepatic arteriovenous fistula in CT angiography. This case report presents the clinical and diagnostic findings of hepatic arteriovenous fistula in four small breed dogs.