I'm taking care of a sick kitty right now. Butter started breathing heavily Monday night, so I took him to the vets Tuesday morning. It turned out that one of his lungs had collapsed. The vet was able to drain away a lot of fluid from his chest, so that has given his some relief. So far the tests they have done on him are inconclusive, but it's either a tumor or a problem with his heart. He will go back to the vets tomorrow for more tests. Right now he is resting and is able to breathe okay most of the time, but he's definitely not in very good shape.
So please think good thoughts for him.