Hi and Welcome to YT!
First, X-ray is not a good way to determine heart size on a Yorkshire terrier. They tend to appear large for the size of their chest. Murmurs are also very common. Best suggestion I can give you is to go directly to a cardiologist and have Monte evaluated there.
My Peek A Boo was diagnosed with an enlarged heart and a murmur at the age of 5yo. He just passed this December at 17yo. |