That is what the cardiologist told me years ago, that Yorkies have a heart shadow & that is probably what Momo has since his heart looked & sounded good. But in the current x-ray, the right side was much bigger (about 30%) than the left. His short of breath & purplish tongue is not a good sign. He also reverse sneezes a lot, but I've recently noticed him coughing when lying down & when playing tug of war, like he's trying to clear his air way. The thing that confuses me is that he has no heart murmur & his heart sounds good, according to vet. Vet didn't even bring up any further tests (I had to ask him) he did mention that Momo could've been in an awkward position when they took the x-ray.
I am leaning on going w/a specialist...