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The Daily Vet by petMD

The Daily Vet is a blog featuring veterinarians from all walks of life. Every week they will tackle entertaining, interesting, and sometimes difficult topics in the world of animal medicine – all in the hopes that their unique insights and personal experiences will help you to understand your pets.


In honor of the fact that February is American Heart Month, I thought it would be a good idea to talk a little bit about heart disease in cats. So, here’s a little information you may not already know.

In cats, the most common heart disease seen is hypertrophic cardiomyopathy. Commonly called simply HCM, feline hypertrophic cardiomyopathy is a disease of the heart muscle. In affected cats, the heart muscle becomes thickened and eventually the heart is unable to pump blood efficiently and effectively.

Hypertrophic cardiomyopathy is seen in both purebred cats and mixed breeds. We do not understand all of the factors that cause HCM, but in some breeds, we do know that HCM has a genetic base. In some of these breeds, genetic tests are available to determine whether the cat has the mutation that causes hypertrophic cardiomyopathy. However, genetic tests are not available for all affected breeds at this point in time.

Symptoms of hypertrophic cardiomyopathy in cats are usually a result of heart failure; they include:

  • difficulty breathing
  • increased respiratory rate
  • increased respiratory effort
  • increased heart rate
  • weakness
  • lethargy
  • lack of appetite
  • fainting
  • sudden death

In some cases, HCM can also cause a cat to develop blood clots. Most commonly, these blood clots become lodged at the end of the aorta, causing a condition known as aortic thromboembolism. This is sometimes also referred to as saddle thrombus. Cats suffering from aortic thromboembolism will suddenly become paralyzed in their hind legs, or will have a difficult time walking. The hind legs may become cold to the touch because of the lack of circulation and you may not be able to find a pulse in the hind legs. This condition is extremely painful for your cat, as well.

Hypertrophic cardiomyopathy is usually diagnosed through an echocardiogram, which is an ultrasonic examination of the heart.

Treatment of hypertrophic cardiomyopathy is aimed at controlling the symptoms of heart failure. There is currently no cure for the disease. Diuretics, such as furosemide, are commonly used to reduce the fluid accumulation in the lungs that occurs as the heart fails. Other medications that are used include ACE-inhibitors such as enalapril or benazepril, and Pimobendan, which is also known as Vetmedin.

There are other forms of heart disease that may also be seen in cats. Dilated cardiomyopathy is a heart disease that was once commonly seen. However, with the discovery that taurine deficiency was the main cause of dilated cardiomyopathy, most commercial cat foods increased the amount of taurine in their formulations and dilated cardiomyopathy is now seen much less frequently.

In contrast to the thickened heart muscle that causes the heart to be enlarged in hypertrophic cardiomyopathy, cats with dilated cardiomyopathy have enlarged hearts because the chambers of their hearts are dilated, with more blood than normal in each chamber. This means the heart has to work much harder to pump the blood, resulting eventually in heart failure.

Symptoms seen with dilated cardiomyopathy are similar to those seen in cats with hypertrophic cardiomyopathy. This condition is primarily seen in cats that are eating an unbalanced diet.

Have you had a cat that suffered from heart disease? Share your experiences with us.

Dr. Lorie Huston 

Image: Antonín Vodák / via Shutterstock

Comments  3

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  • HOCM
    02/27/2012 06:49am

    As I've mentioned previously, my Owen has hypertrophic obstructive cardiomyopathy (HOCM).

    Our vet sent us to the cardiologist when a heart murmur was heard and a blood pressure couldn't be obtained. (It would be extremely high and then extremely low.) The cardiologist did an echo and made the diagnosis.

    Owen's condition hasn't gotten any worse since he was put in Ace Inhibitors and Beta Blockers.

    I'm so glad my critters get a blood pressure check with each checkup and especially glad our vet suspected a heart problem and Owen got the necessary help. He's doing great and goes for checkups with the vet every 5 months and the cardiologist every 8 to 9 months.

  • Het positive
    02/27/2012 01:26pm

    Great post, Dr. Huston. Thanks.

    My beautiful 5 year old Ragdoll was born right before the time that HCM genetic testing became available. I had him tested at one year old by WSU and he is hetero positive. (For those who may know know what that means -- he has inherited from his parents one copy of the mutated gene. Homozygous positive cats have inherited two copies of the mutated gene, typically thought to be the more serious of the 2 possibilities.)

    I was stricken at first, very worried and upset. He has had 2 echocardiograms and each one shows what "may or may not be" some (very mild) heart wall thickening but otherwise he appears healthy, active, and the vet says no medication is indicated at this time. I am faithful with twice-yearly check-ups and watch him closely.

    There is evidence that het pos cats may develop HCM more often than cats who test negative, but it is definitely not a "given" that they will develop HCM during their lifetime. I try not to worry about the future, just be as proactive as possible and enjoy my beautiful boy.

    BUT, I will tell you that when we adopted his brother 3 years later (another Ragdoll), I carefully chose a breeder who tested her breeder cats for HCM, and both of his parents are negative. This doesn't mean that he will NEVER develop any HCM in his lifetime, but it does mean that he does not carry the mutated gene that we are aware of at this time. (There may well be more found in the future.)

    I am sad and sorry that my first boy is het-positive. To prevent this from happening, I support responsible breeding and genetic testing, when available, for breeder cats.

    But what's the bottom line? Unfortunately, nothing lives forever. So loving any living creature carries risks, and HCM-positive or not, the risks are almost ALWAYS (in my humble opinion) well worth taking for the joy and privilege of loving.

  • Misdiagnosed?
    02/27/2012 01:52pm

    My male 7 year old cat was diagnosed with HCM in January of 2010 by ECHO. I was told then that he probably had a year to live as he could not tolerate any of the medication we tried. He is still here today and the only change I've seen is that he has gotten fatter. He has not developed any of the symptoms and has no impairment other than a murmur. I'm wondering if he really has HCM. He gets outrageously anxious about car trips and/or vet visits. Could stress have affected the ECHO?

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