Update
Thanks everyone. J.C. had many friends, some he never even met, The vet called yesterday with a preliminary report from the university. J.C. died from a form of heart disease that they have never seen before. They don't know the exact cause and are waiting for more test results. She sent me an e-mail explaining what they know at this point:
"Hi Gary,
Here is what they are technically calling JC's condition: "Idiopathic Eosinophillic Myocarditis" - their other technical description is massive multifocal eosinophillic myocarditis.
Idiopathic - is the term we use when we don't know what the cause is.
Myocarditis - means inflammation of the heart muscles
Massive just means large amounts of lesions.
Multifocal - means multiple distinct areas affected.
Eosinophils are a type of white blood cell - and basically these invaded the heart tissue/muscle, and caused inflammation. At this time they cannot find a cause for this invasion/infiltration - but they are doing additional testing. these cells tend to be stimulated by parasites, allergies and inflammatory processes like these -however they cannot find any evidence towards these problems.
The inflammation in the heart muscle - would have led to the heart not functioning properly, and likely causing the cough (kind of like due to heart failure) and would be the cause of his heart attack.
These lesions could not be found anywhere else in the body or in other tissues.
There was no dilated cardiomyopathy. The right ventricle was maybe somewhat dilated, but not to an extent to ever cause symptoms or death according to the pathologist."
If whatever this was hadn't taken him, he probably would have made it to a respectable old age because he a good healthy heart otherwise. She said J.C. will be kind of famous at the U for a while because they will be talking about his case for a long time to come.