Use of cardiac gated computed tomography in the diagnosis of a rare congenital cardiovascular anomaly in an adult alpaca.

A 5-year-old female alpaca was presented with respiratory distress and lethargy. Thoracic radiographs revealed a cranioventrally distributed alveolar pattern, caudodorsal bronchial pattern, cardiomegaly, increased soft tissue opaque content in the ventral thorax, and rounded soft tissue opaque structures craniodorsal to the carina. Cardiac gated CT demonstrated a patent ductus arteriosus, ventricular septal defect, complete left atrioventricular valve atresia, partial anomalous venous connections from the cranial pulmonary veins to the azygous and cranial vena cava, severe right-sided cardiomegaly, pleural and peritoneal fluid, and severe hepatic congestion. These findings were confirmed with necropsy.