Hypertrophic Cardiomyopathy

Echocardiograms of feline hearts showing normal heart (left) and heart affected by HCM(right); - note thickened wall of left ventricle (LV - Left Ventricle, RV - Right Ventricle, LA - Left Atrium, RA - Right Atrium)

Bisected heart from a Maine coon cat with severe HCM (heart weight, 35 g). Section has passed through bellies of both severely hypertrophied papillary muscles, which have caused systolic midventricular cavity obstruction and endocardial contact plaques (arrow). LVOT is narrowed. Moderately enlarged left atrium harbors a large thrombus (left half).

"Maine Coon. A severe form of heart muscle disease (hypertrophic cardiomyopathy) is seen in some Maine Coon cats. Affected cats may begin to develop problems as early as three months of age, while less affected cats show signs of heart failure by two to four years of age. A recent study showed that 33% of Maine Coon cats had a genetic abnormality related to hypertrophic cardiomyopathy." This information was taken from https://vcahospitals.com/know-your-pet/heart-disease-cardiomyopathy-in-cats (This is why we test our kittens before they go to their new homes)

Please contact your vet for further testing and the MYBPC3-A31P Mutation can be located using https://optimal-selection.com/ for genetic testing and their turn over time is about a week. If you choose to use UCDAVIS be ready to wait up to 3-8 weeks depending on their facilities https://vgl.ucdavis.edu/test/maine-coon-hcm


Feline Hypertrophic Cardiomyopathy (HCM) is a condition that causes the muscular walls of a cat’s heart to thicken, decreasing the heart’s efficiency and sometimes creating symptoms in other parts of the body, and without care will lead to a slow and painful death. Not all genes that cause HCM have been identified yet.

It's part of our job to make sure we keep up to date with yearly ultrasounds and/or X-rays of our cats hearts to make sure they are not carriers of an unidentified gene or abnormality. This means everyone- even if the kitten goes home with you there will always be a chance of an undiscovered gene. Yearly tests must be done and I request that if any lines of mine pop up in the future to be a carrier of an undiscovered gene to please contact me Kosmos ASAP, so I can locate the lineages and reach out to past/current breeders I got the lines from and we can contact other who have the same lines and make sure everyone is okay and try and spread out the help as much as we can as fast as we can, our hearts and thanks go out to you for all your help and understanding.

Please also note: The Embrace Insurance coverage we provide is SPECIFIC to issues such as this. If in the event your baby has HCM down the line, Embrace insurance if you "read your coverage" They got your back in this time of need.- In the future we will have our own insurance company that will have coverage according to breed and (animal species). - If new studies show there is multiple genes across different breeds it will be covered. We want to help continue education and understanding of this planet and who we share it with. And hopefully someday our facility will provide cures.

"These studies have also identified HCM in cats that do not carry the MYBPC3-A31P. The incidence of HCM in these studies was 5.4% in cats that were negative for the A31P mutation, and 5.4% with the mutation. Therefore, the MYBPC3-A31P mutation is not the sole cause of HCM in Maine Coons. The other causes are not known at this time."

  • Alleles: N = Normal (Not a carrier of a specific discovered genes)

  • HCMmc = hypertrophic cardiomyopathy-associated mutation- if your feline carries 2 copies, your feline will have a life expectancy of up to 4 years. If they are carrying a single allele they have a longer life expectancy, however they can still get HCM sometime down their life, regular tests should be done to avoid suffering.

  • N/HCMmc

  • N/N = These genotype are not predicted to be at increased risk of HCM and cannot transmit this hypertrophic cardiomyopathy-associated mutation to their offspring, but yearly testing must continue to be done due to not all genes that cause HCM are found.

  • Asymptomatic: Some cats with HCM may never show any clinical signs of heart disease and go on to have a normal life expectancy (Please note proper diet can play a big role) and yearly ultrasound scans must be done to insure there is no other signs.

  • Mild clinical signs: Affected cats can show increased efforts with their breathing "heavy breathing" and irregular heart-beat, they may faint (syncope) or they may be less able or willing to exercise and play than they used to.

  • Congestive Heart Failure: Fluid accumulating on or around the lungs can cause cats to struggle to breathe and collapse causing suffocation and death in a slow painful manner.

  • Aortic Thromboembolism: For some severely affected cats, a blood clot produced in the heart can block off the blood supply to the hind legs causing a very painful paralysis.

  • Sudden death: For a small minority of cats, the first sign of the disease is sudden death!

  • Treatments: Although HCM has no known cure there are specialized care plans made available by your vet and other sources to help create a better easier time for their life expectancy. Medication can help such as topical skin medications and injections. - Please note this is not a cure, this can only extend the life of the animal. But please remember to weigh the benefit of quality of life VS quantity. We want the best QUALITY we can get, what use is a long life if it's full of pain and displeasure!