Sorry, don't have my list handy , but someone asked about ferrets having
surgery with cardiomyopathy.  I can recall two cases where that was done --
but in each case the reason was a very, very serious, immediately life
threatening one.
 
Bruce Williams had a 10 year old who had both insulinoma and cardiomyopathy
and the insulinoma was to the point where it could not be controlled.  The
ferret did not survive the surgery.
 
We had Ruffle, who was a deformed ferret with multiple handicaps who also
had severe insulinoma -- to the point where she also had Phenobarbitol
among her meds to try to avoid her destroying her heart with her grande
mal seizures but then she also developed liver cysts that were immediately
dangerous.  She had the insulinoma and the cysts tackled in surgery to try
to spare her an agonizing and rapid death from the cysts and maybe give her
extra time.  It was NOT an easy thing to do and it took the best ferret
surgeon we've even known, but it worked fine.  She did pass away maybe a
half year after (Can't recall off-hand) but she'd had many other things
go wrong by then, too.  (Like humans who have serious intellectual
handicaps -- one of her many birth problems -- she had all sorts of things
fail at once from separate causes -- all going at the same time.)
 
Anyway, it boils down to surgery during cardiomyopathy not being something
I've heard of or experienced anyone doing lightly.  Things may have changed
in the years between, but you asked for all our experiences...
[Posted in FML issue 2986]