Re: [FH] Studies on feline murmurs
HCM is more common for several reasons. In most cats HCM doesn't show up
until after four years of age and by then they will have reproduced and
passed it to kittens in pedigree cats. Screening by ultrasound is a fairly new
development. A male champion cat with HCM which showed at age 11/12 could
have had hundreds of kittens, all who could have been bred on. And the
limited gene pool and matings of relatives will make this worse.
I have 18 cats, 17 are pedigrees and 6 have serious heart disease and 4
have minor disorders of the heart they were born with. All except three are
symptomless but were diagnosed on echo. My breeding girl is a totally
different line and HCM screened as negative for her last two echos.
The other reason is cats are living longer due to better diets and vet
care. So more cats who are elderly are surviving to develop HCM. And in the
past without the internet people weren't in contact so much so cases tended to
be isolated. The detection of HCM is impossible without ultrasound. Many
HCM cats would have been treated for asthma or infection in the past.
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