Mitral valve reconstruction in a toy-breed dog.

A 9-year-old 3-kg spayed Maltese with congestive heart failure that did not respond to aggressive medical treatment underwent cardiopulmonary bypass and mitral valve repair. Prior to surgery, echocardiography revealed a markedly dilated mitral annulus, left atrium, and left ventricle; prolapse of the parietal mitral valve leaflet; and mitral regurgitation. Hilar pulmonary edema was evident on thoracic radiographs. After surgery, echocardiographic measurements of the heart returned to reference range, all medication was discontinued, and the dog did not have clinical signs of heart disease.