Echocardiographic assessment of congenital aortic stenosis in dogs.

Eleven dogs with congenital aortic stenosis were studied with M-mode echocardiography. In these dogs, the aorta was increased in dimension during diastole (P less than 0.02) and systole (P less than 0.05). The left ventricular outflow tract was decreased in dimension (P less than 0.01). There was premature, early systolic closure of the aortic valve in 45% of the dogs. Concentric hypertrophy of the left ventricle was confirmed via echocardiography, as evidenced by increased dimension of the left ventricular wall (P less than 0.01) and interventricular septum (P less than 0.01).