Abstract
Background: Portosystemic shunt and atrial septal defect (ASD) are generally congenital diseases in dog. Rarely, dogs with congenital vascular anomalies could be related to other vascular anomalies.
Case Description: A 1-year-old neutered male Maltese dog weighing 1.7 kg was presented for further evaluation of congenital portosystemic shunt (CPSS). CPSS was diagnosed as porto-caval shunt by computed tomography. Surgical attenuation was performed. Although prognosis after CPSS attenuation was good, the dog was presented with exercise intolerance at one year after the operation. Generalized cardiomegaly was observed by thoracic radiographs. Echocardiography revealed pulmonary hypertension and right-to-left shunting ASD.
Conclusion: The present study reports a rare case of CPSS concurrent with ASD in a dog. As dogs with CPSS might have associated with other vascular anomalies; therefore, echocardiography is recommended for early diagnosis of other cardiovascular anomalies.

Key words: Atrial septal defect, Dog, Echocardiography, Portosystemic shunt, Pulmonary hypertension