Echocardiographic findings of a valvular aortic cyst in a dog.

A 12-year-old, 19.8-kg, female neutered Nova Scotia Duck Tolling retriever was referred for investigation of a heart murmur. The dog was asymptomatic at the time of examination. On cardiac auscultation, a soft (2/6) diastolic heart murmur, louder at the left cardiac base, was present. Two-dimensional transthoracic echocardiography revealed a cyst-like structure attached to the aortic valve leaflets. Doppler examination showed that the cyst was fluid-filled and connected to the aortic and ventricular lumen. A moderate aortic valve insufficiency was also present. The left heart was mildly dilated. An echocardiography was repeated eight months later, and no relevant progression of the lesion was noted. The dog remained asymptomatic. An aortic cyst is an unusual congenital or acquired condition described in humans, but never reported previously in a dog.