Hypertrophic cardiomyopathy (HCM) testing in cats: a note for owners

Aims
	To identify cats free from hypertrophic cardiomyopathy (HCM) in specific breeds of cat.
	To collate data for investigation of a possible genetic basis to HCM in a given breed by a breed club nominated person, geneticist or veterinary surgeon.
	To advise the owner, breeder and cat's veterinary surgeon when an abnormality has been identified and recommendations about any further investigation, if indicated.

Methods of heart testing
1	Auscultation: examination with a stethoscope This is an essential part of examining the animals' heart and circulation. Any heart murmurs are identified, timed, localised and graded (grade 0 - 6). Careful note of the heart rhythm is made. Abnormal heart rhythms may occur without murmurs in HCM. It may be difficult for the veterinary surgeon to detect a quiet murmur in a noisy room or in a cat which fidgets or purrs. Some murmurs may increase or alter at different heart rates, or due to stress or excitement. If a significant murmur is detected, the veterinary surgeon may advise that the condition should be investigated further. Auscultation does not provide a conclusive diagnosis; further investigations are required. Although all veterinary surgeons will check your cat's heart, the Feline Advisory Bureau-Veterinary Cardiovascular Society HCM scheme will use a veterinary cardiologist who has received training and has passed post-graduate examinations.
2.	Electrocardiogram (ECG) This is always indicated if an abnormal heart rhythm is detected.
3.	Echocardiogram (with Doppler) Two-dimensional echocardiography (ultrasound examination of the heart) allows visualisation of a "slice" through the heart in real-time. M-mode and Doppler (spectral, with or without colour flow mapping) echocardiography allows measurements to be taken and compared with normal values. HCM is usually evident using these techniques. In some cases, it is difficult to be certain whether a cat has mild disease. Veterinary cardiologists normally carry out Doppler examinations as this is a very skilled technique which requires considerable expertise and experience.

Further information
If you have questions about HCM the cardiologist testing your cat will be willing to discuss the results of the tests with you, which are summarised on the certificate of heart testing.

Limitations of heart testing
Echocardiography is not a perfect tool for the diagnosis of HCM; however it is the most sensitive method currently available for detecting early signs of disease. Auscultation (listening with a stethoscope for abnormal heart sounds such as heart murmurs) is a less accurate means of detecting affected cats as a significant percentage of cats with HCM will not have an audible heart murmur.
HCM can occur at any age and therefore a single normal echocardiogram does not guarantee that the cat will remain free of the disease. Cardiologists recommend that breeding cats should have an annual echocardiogram during their breeding years. Examining retired cats periodically is also advantageous as this may allow the identification of affected cats that have offspring in a breeding program.

For further information, and for a list of cardiologists who are involved with screening for feline hypertrophic cardiomyopathy, go to the website of the Feline Advisory Bureau.

If you have any questions or comments about this site's content please contact the VCS Secretary