Feline hypertrophic cardiomyopathy

Feline hypertrophic cardiomyopathy (hcm) is a disease affecting cats in which the walls of the heart become increasingly enlarged.

This is a compilation of information on the disease for veterinarians and pet owners, including a list of other HCM Internet resources. (Standard disclaimer applies: I'm not a vet and this is not medical advice.)

Diagnosis in early stages can be tricky, but here are the symptoms: lethargy, poor appetite, panting/troubled breathing. Often, a feline will develop a heart murmur along with HCM; while the HCM can be treated if detected early, the murmur will probably never go away (but it isn't anything to worry about).

Even after treatment, weakness or paralysis of the back legs should be watched for -- blood clots can be developed and lodged in each leg ("saddle thrombosis"). This is a grave condition and must be treated immediately (within minutes, maybe hours at best) for the feline to survive.

Prognosis is not favorable -- no cure is known at this time. In a fairly recent study, cats with HCM lived for an average of around 736 days, but I've heard of HCM-afflicted cats living for four or more years before heart failure.

If diagnosed early, medication can slow the process down. Late diagnosis is usually postmortem, or when the disease has reached an acute state.

The cause of HCM is believed to be genetic. It has been noted that an alarming increase of cats (and dogs), especially younger ones, afflicted with HCM in recent years.

The best hope for HCM, it seems, is to diagnose animals which carry the HCM gene and don't let them breed.

Who bred your HCM-afflicted cat?

Treatment is through medication to both thin the blood and retard the growth of the heart wall. Several types of vet-prescribed medications can be administered: atenolol (generic for tenorim, a beta blocker, which lowers blood pressure), lasix or other diuretic, and Cardizem. Baby aspirin (normally fatal to cats) can be given twice a week to thin the blood.

It can be a struggle getting the medication down the hatch, and few cats seem to be easily "tricked" into eating food laced with meds. The best technique is to kneel on the ground with your feet crossed, the cat held between your knees. Open the jaw with one hand and insert the medication with the other. It can also help to give meds before they eat their first meal of the day, to reduce the chance of vomiting it up.

It may be appropriate, later down the line, to take the cat off diuretics (which act as an appetite supressant and can also dehydrate the cat).

Other treatment is focused on encouraging strength and optimum health by giving the feline the best living conditions possible; this also happens to be sound advice even for cats who aren't sick -- a diet of name-brand, commercial pet food is probably worse for cats than a human on a diet of fast food:

• Feed high-taurine, quality foods. Commercial cat foods that seem to meet standards include Bench & Field, Nature's Recipe, Wysong, Katz-n-flocken. Other healthy foods reported to be liked by some cats include plain, cooked oatmeal; steamed broccoli; cooked liver. Avoid salt and salty foods. (Proper diet for HCM-afflicted cats is of utmost importance.)
• Exercise should be with caution (feline should not be stressed), but is also important.
• Give several holistic treatments -- these are all from The New Natural Cat by Anitra Frazier, a book I highly recommend; get out your credit card and buy it online at a discount from amazon.com -- it's well worth the cost.

  Treatments for HCM from the Frasier book:

  • vitamin E supplements in wet food
  • make your own Vita-Mineral Mix (recipe given in book) and add to food
  • give weekly or daily "kombu broth" mixtures (recipe in book)
  • daily supplement of "Pet Tinic" (rich in B-complex vitamins)
  • Hawthorne berry supplement, a mild diuretic, to encourage self-confidence
• More herbal supplements and treatments are given on Holisticat's HCM page. One important one is dandelion, a natural diuretic.

Links of interest

• feline-heart, ``A list where members can discuss feline heart conditions and treatments.''
• Huge site on feline hcm.
• A "succinct review" for veterinarians by Chuck Newman, PhD DVM, explains the difference between the less common dilated cardiomyopathy and hypertrophic cardiomyopathy, gives clinical signs and detailed information on medication and treatment.
• Clear, concise page discussing treatments from the UK's Feline Advisory Bureau.
• West Boulevard Veterinary Clinic (Vancouver) has an informative page about HCM, the "silent killer."
• Hypertrophic Cardiomyopathy Association -- for humans, but good general info on the disease.
• MedLine search abstracts on feline HCM.
• HOLISTICAT is a mailing list for discussing holistic feline care; there's quite a bit of HCM discussion on the list, as it has unfortunately become quite a common feline disease. Check the HOLISTICAT site for subscription instructions.
• Do this Google search on feline HCM to list up-to-date sites.

Here's a positive anecdote from Robert Durlak on his barely one-year-old cat, "Y," who'd been diagnosed with HCM in 1995 after going into heart failure:

Fortunately, there's an animal cardiologist in my area, a fellow named Joel Edwards, who is apparently very highly regarded in vet circles as a pioneer researcher. The cat was put on a rigorous dosage schedule of lasix, enacard, diltiazem and Ipropanol as well as thrice daily applications of nitro paste in his ears for six months. At this point, he only gets enacard and diltiazem with an occasional portion of baby aspirin. He was raised on science diet, so there was no real need to alter his food.

In X-rays, his heart walls have decreased in size about 60%, and other than limiting his exercise, he's doing very well. His reversal may be a bit of an anomaly regarding this disease... even Edwards is surprised at how well the cat is doing.

Knusper, pictured above, was diagnosed with HCM in Dec. 97. He's quite well now, after it was determined in 2001 that his ``illness'' was actually a misdiagnosis! The medication took away his appetite and he got thinner and thinner ... until he was completely taken off all medication and then immediately sprung back to his former lively, roly-poly self.