Heart disease in Rabbits?

Question
I recently lost my pet rabbit of 6+ years.  Over the past year or so he had been getting less active, sleeping more, but was still eating well, hopping around and comfortably relaxing.  About 5 days before his death, I noticed he had not pooped a lot, and was drinking very little water.  We gave him lots of fresh leafy greens to eat, since we had experienced GI stasis w/ him several years before, during one of his shedding periods, and at that time the leafy greens turned him right around, and he was fine.  This time, he ate all of the greens, and some celery, and was pooping a little, but he still seemed off, and his pee had a very bad, strong odor.  I took him to the vet the next day and she said his digestive system was off, she gave him some crtical care solution and hydrated him though his skin.  He seemd better the next day, and I again gave him the critical care food, as per the vet's instructions. He ate the food without issue.  A couple of hours later he started to eat some pellets, then he suddenly started retching, and coughing up drool and some chewed pellets.  His breathing was slowing as well.  I immediately rushed him to the vet, they tried to help him, but he died. When I last held him, right before the vet took him, he was also loosing control of his rear legs, he couldn't sit upright anymore.  The vet had said there was a lot of fluid around his heart and lungs, and I think she said fluid in his lungs as well.  The vet suspected he had heart disease, not GI stasis, and that is why his condition declined.  Have you heard of heart disease, or any of the symptoms involving fluid around heart or lungs?

Answer
I have heard of heart disease in rabbits, a friend's rabbit died of it last year.  There is an article on two other rabbits with it at http://www.rabbitnetwork.org/articles/hearts.shtml

Heart disease in rabbits is very serious, and very expensive to treat.

I am sorry that you lost him, but if he did have heart problems, neither of you would have been happy since it is very difficult to treat.

Kim