Left ventricular injection study in a dog with hypoplastic aortic root, subaortic stenosis (SAS) and mitral regurgitation (arrow). Note the small diameter of the aortic sinuses of Valsalva (SV) which normally exceeds the diameter of the descending aorta (DA). The thick mitral valve and reduced diameter of the mitral orifice (M) are consistent with mitral dysplasia and mitral stenosis. The large, non-contractile left atrium (LA) was due to mitral valve disease and atrial fibrillation.