For cardiomyopathy info go to
http://www.smartgroups.com/groups/ferrethealth (Including the Files
where there is compilation)
http://fhl.sonic-weasel.org/ (the easily searched FHL Archives)
http://www.miamiferret.org/fhc
I think one of the vet website links at
http://www.ferretcongress.org
and the FML Archives at
http://listserv.cuny.edu/archives/ferret-search.html
 
Some standard meds used include Enacard, Digoxin, Lasix, and various
others depending on the presentation, particulars, and the amount of
compromise.  With careful care it is not unusual to get 6 months or
more months for a ferret, sometimes even times over a year more.  Of
course, the cases vary widely.
[Posted in FML issue 4047]