[Resolution of ascites after successful balloon dilatation of cortriatriatum dexter in a dog].

A 9-month-old male American Cocker Spaniel was examined for progressive abdominal distension, tachypnoea, and decreased appetite. Physical examination revealed signs of congestion in the caudal body half only (ascites, congested saphenic vein), and abdominocentesis yielded a modified transudate. Echocardiography revealed an abnormal membrane in the right atrium and cor triatriatum dexter was diagnosed; the diagnosis was confirmed by cardiac catheterization. Successful treatment consisted of balloon dilatation of the pinpoint opening in the abnormal membrane. The dog recovered well, with the ascites resolving within a week, and its further development was normal.