153.35.71.22 Comments Mitral valve disease in older dgos is related to thickening of the valve over time. As the leaflets get thicker, the valve begins to leak - thus the murmur.
Many dogs have low grade murmurs with no evidence of heart disease.
Usually the need for the tests are based on the other findings. A dog with a low grade murmur, no physcial signs and an otherwise normal exam would not generally receive a cardiac workup.