5. Cardiomyopathy.
 According to another exemplary embodiment, another feline patient was treated for a generalized inflammatory disorder of unknown etiology and feline cardiomyopathy diagnosed via echocardiography with a single therapeutic dose of dental derived MSCs given intravenously. Prior to treatment, the patient's condition was not stabilized the patient was displaying marked lethargy. After treatment, echocardiography measurements showed noticeable improvement of the cardiomyopathy symptoms. Further, the patient showed dramatic improvement of the general lethargy noted pre-treatment, and showed an activity and appetite associated with a normal individual.
Read more: http://www.faqs.org/patents/app/20120269786
Google stem cells and you'll find mention of its use for other diseases and issues. Here are some links. In those cases it might be useful if the pet can withstand the surgical procedure.
There are two US companies, one being Vet-Stem, that do stem cells for pets. Their name pops up often linked to vet practices because only surgeons do the stem cell administration and are specially trained. The process is pricey at $1500 to $2000 or more depending. But it requires surgery to extract the stem cells from the patient and HCM cats in general cannot tolerate surgery, certainly not Myrna.
Here's a report from 2011 about stem cells being a niche practice in vet med; very pricey; and requires surgery-something the majority of HCM cats cannot tolerate. Certainly, Myrna at this stage, cannot have surgery.
Blog post from 2010 that states unease with Vet-Stem stem cell research.