Case Report: Concurrent ventricular septal defect, pulmonic stenosis, and intrapulmonary arteriovenous anastomoses in a Korean raccoon dog (Nyctereutes procyonoides koreensis)

A 3-month-old intact male Korean raccoon dog ( Nyctereutes procyonoides koreensis ) was rescued and admitted to the Jeonbuk Wildlife Rescue Center with lethargy, dehydration, and dermatologic lesions consistent with Sarcoptes scabiei infestation. Physical examination detected a grade IV/VI systolic murmur, and thoracic radiography revealed generalized cardiomegaly. Transthoracic echocardiography identified a perimembranous ventricular septal defect (VSD) with left-to-right shunting. Although no distinct structural abnormalities of the pulmonic valve were observed, increased pulmonic flow velocity (3.87 m/s), mild pulmonic regurgitation (1.68 m/s), and post-stenotic dilation of the main pulmonary artery supported a diagnosis of pulmonic stenosis (PS). Agitated saline contrast echocardiography demonstrated intrapulmonary arteriovenous anastomoses (IPAVAs), with microbubbles appearing in the left heart after the fourth cardiac cycle; this shunting decreased following oxygen supplementation. Five weeks later, thoracic radiography demonstrated a reduction in cardiac silhouette size, although cardiomegaly persisted. Echocardiography demonstrated progression of the VSD to bidirectional shunting. Systolic doming of the pulmonic valve, together with increased pulmonic flow velocity (4.39 m/s) and pulmonic regurgitation velocity (2.07 m/s), indicated worsening PS. Repeat agitated saline contrast echocardiography revealed microbubbles in the left heart within four cardiac cycles and in the abdominal aorta, indicating a right-to-left shunt component consistent with bidirectional shunting. These findings were attenuated after oxygen supplementation. The Korean raccoon dog subsequently died during anesthetic induction for further diagnostic imaging. Postmortem examination confirmed a perimembranous VSD and type A valvular PS characterized by fused commissures, with concurrent right ventricular hypertrophy, dilation, and interventricular septal thickening. To our knowledge, this case report is the first to describe the concurrence of VSD, PS, and IPAVAs in a Korean raccoon dog. It suggests that progressive PS may contribute to reversal of shunting across a VSD.