Feline Hypertrophic Cardiomyopathy: HCM Is a Serious Disease in Cats

All cat owners and breeders should be aware of this deadly condition, thought to be genetic. While the long-term prognosis for cats afflicted with this incurable disease is not good, early detection via an echocardiogram and treatment with medication can considerably slow the progression of the disease.

What is HCM?

The Cat Fanciers’ Association states that HCM is a common cardiac condition that most often affects middle-age cats, but has been seen even in very young cats. Tragically, cats with the disease may die suddenly after developing a blood clot in the heart, having displayed no symptoms of ill-health.

A cat’s heart that is affected by HCM will have thickened left ventricle walls. Rather than growing larger outwardly, the walls of the heart grow inward, restricting the amount of blood that can be pumped through the ventricle. As the condition worsens, it becomes increasingly difficult for the heart to perform its job, and the heart eventually fails.

Symptoms of HCM

Many cats with HCM are never diagnosed as having the condition until it is too late – that is, posthumously. The reason for this is that the disease often displays no symptoms at all, or exhibits symptoms that can easily be mistaken for other conditions. However, the following symptoms should be taken very seriously, as they can be indicative of HCM:

Causes of HCM

So far, the cause of Feline Hypertrophic Cardiomyopathy is unknown; however some studies suggest it to be genetic. Certain breeds appear to be more commonly afflicted, including Maine Coons, Bengals, American Shorthairs, and Ocicats. If a veterinarian believes a cat to be at risk for the condition, he or she may recommend that further screening be undertaken.

Screening for HCM

An echocardiogram, an ultrasound of the heart, is the best method of detecting moderate to severe HCM; however it may be unreliable in very mild cases of the disease. An echocardiogram can be an expensive test, often costing upwards of $400 at a veterinarian’s office, but it is vitally important if HCM is suspected.

Boolean’s Story

Boolean, an otherwise healthy, male Ocicat was diagnosed with a heart murmur when he was less than one year old. Suddenly, at five years of age, Boolean began to have trouble walking. His owner noticed that he appeared to be having trouble moving his back legs. He was rushed to the emergency vet, and an x-ray and physical exam determined that Boolean was having trouble walking because he was suffering from constipation.

Unfortunately, an enema failed to resolve Boolean’s problems, and during the night he went into cardiac arrest at the veterinarian’s office. It was only after he suffered this heart failure that an echocardiogram was performed, revealing that he was afflicted with HCM. The problems with his legs were revealed to have been caused by a blood clot that had blocked the terminal aorta, causing paralysis of the back legs. Boolean passed away that night.

Sadly, Boolean’s story is not uncommon. Heart murmurs are not always indicative of HCM, but they should be considered a warning sign. Any cat owners – especially owners of at-risk breeds – whose cats display warning signs of HCM should consider further screening for the disease. If treated promptly, cats with HCM may live years longer than those who do not receive treatment.

Jan 17, 2009 8:58 AM

Guest :

I wish I would've known this information sooner. My family is presently suffering with the devasting news that our beloved Sam has this disease. He had been to the vet office this past September and never showed any signs. Two nights ago he went into congestive heart failure. He is presently hospitalized and in a guarded condition. He has formed a clot in his heart. We are at a loss right now and only wish to be able to take him home soon. His prognosis is six months to a year but we are willing to do anything to give him that much time with us. We just want him to have a good quality of life. Our hearts go out to every family who has had to deal with or lost a member of their family to this awful disease.

Feb 11, 2009 3:24 PM

Guest :

Can this disease come on that quickly? And do vet's know about this disease? Our beloved 6 year old Ocicat died of this sickness. The first vet kept her overnight then sent her home with us the next to continue her suffering. We took her to a second vet, who had no good prognosis and suggested putting her to sleep. She had a check up only months prior. She was a healthy playful kitten, she grew to a good size and weight...then this. RIP dear beautiful Kitten.

Feb 14, 2009 10:27 PM

Guest :

Fric my lovable sweet boy died suddenly on 2/1/2009. He was part coon cat, domestic short hair, long big body since he was a kitten. His routine Vet checked was 11 months ago. Nothing was detected in regards to his heart. He has always big 22-25 lbs. His diet was Science Diet M/d. All I know was that day he had breakfast @ 630am and came to me later and gave me my morning head butt and message. By 10am he was gone. This was the most tragic experience I have gone through. I was driven to the Vet and I had an necropsy, then cremation done. My concern was with his brother Frac. The Vet called me that eve and said that Fric died of HCM. Yesterday, Frac's check up was done and the Vet could hear a heart murmur. My question was, why could this murmur not be detected before. Answer was that it is hard to detect unless you listen very closely. I had complete blood work done to see if he also has a Thyroid problem. You see, Fric was long and big, and his brother Frac is long and thin (15 lbs). So on Tues. I will get the results of the blood work. What I cannot find is the "Cardiac Diet for cats." So if someone could post it and the brand name or web page that would be great. THANKS

Apr 16, 2009 4:01 PM

Guest :

Yes, it can come on that fast. My baby, Colby, an American Shorthair was diagnosed with a heart murmer at less than a year, however, the vet told me most kittens "grow out of it". When we moved 2 1/2 years ago, I mentioned the heart murmer to the new vet, but it had never been an issue, so the note was made, but no one ever said anything about HCM to me, and I was never aware of it. Colby was a normal, healthy cat who was a bit overweight. I came home 2 nights ago and all was normal - he begged for treats and jumped up on the bed for pets as I changed my clothes. 3 hours later, he was having trouble breathing. We rushed him to the vet and oxygen seemed to help. We took him to an overnite facility to have him monitored through the night and be given lasiks and heart meds, but 3 hours after we dropped him off, my angel baby died. It was heart wrenching. I am happy he did not suffer for long, but there was absolutely NO indication of this disease and we were left asking "Why?". We plan on having another kitty in our future (not yet - we are so not ready)and now that I am aware of this disease, I will fork out the money to have an electrocadiogram to be sure we can avoid what happened to Colby. I miss my angel baby desperately!

Apr 17, 2009 5:03 PM

Guest :

our beautiful siamese cat 15 years old was rushed to the emergency vet on the day we left for a cruise which we had booked 12 month's previously.
he was seen by a cardiologist but after a very stressful week for him, where he was in a small cage in the vet's office, we arrived home to an almost skeleton of a cat, who just does not want to eat. We are force-feeding him and are praying he will recover to some good degree. Is this unrealistic?