Hi, Gonslo. Welcome.

From what I've read (and I'm no expert by any means), it's more likely a genetic component that predisposes you to both MG and cardiomyopathy.

http://content.onlinejacc.org/cgi/content/full/38/1/184

If you have breathing problems for any extended period of time, your heart can work harder and become "larger," as in dilated cardiomyopathy. My Dad, who had a bad aortic valve for years which lead to a high BP (another cause), had DCM.

MG affects skeletal muscles. I don't know if they've really studied effects of MG on the heart very well. Some of the GI tract is affected by MG and that is smooth muscle so I don't think there is enough info on all this to make any kind of good conclusion.

I'm sorry you are having to deal with this very tough health issue. I hope the procedure goes well.

Has anyone checked your kidney function? Problems with the heart directly affect the kidneys. If they haven't, please make sure someone does! My Dad had kidney failure from his heart problems.

Annie