Yes, it is one of the sad things about this breed: heart disease is endemic and only the rare cavalier owner will escape it. Exceptions are few, not general, and there's now an absolutely alarming level of acceptance of this condition in the breed by both pet owners and breeders. We need to always remember dogs suffer with this. I am also sick of breeders who rush to state how it is the most common illness in elderly dogs generally. Yes: ELDERLY dogs. MOST cavaliers never reach an age which would be considered truly elderly for a small breed, because they die of heart disease that on average hits more than 50% when they are only age 6. SIX. And that means the other half have murmurs before age six!!! If a population of humans, say in San Francisco, routinely began to suffer from heart murmurs leading to congestive heart failure by the age of 40 and half the population had them anywhere from age 7-39, there's be a national outcry.
Almost every cavalier owner will eventually have a dog with syringomyelia (as affected rate is about 70% at age 6+), though not all, thankfully will have symptoms or severe symptoms (which does NOT mean this isn;t an urgent and severe situation already!). Almost every cavalier will have a skull malformation causing its skull to be a bit to small for its brain, which will sometimes be forced out into its spinal canal. For some dogs, this alone will cause symptoms. Nauseatingly, some breeders also now argue that maybe the skull malformation is 'normal' for the breed. A bred-in widespread malformation that is known to be connected to severe pain is NOT and can never be considered normal except by people who are truly sick in the head themselves. CM in cavaliers is, sadly, endemic -- a very different thing from 'normal'.
All of this is totally unacceptable. The fact that no national breed club in the UK, Ireland, US, Canada or Australia -- the largest centres of CKCS breeding populations -- even requires a cardiologist test a cavalier for a heart murmur before breeding, much less places any restriction at all on breeding dogs below the MVD protocol or breeding them with murmurs, even after about two decades of serious attention being given by researchers to the problem, goes to show how intent a broad consensus of breeders in the show world are on (NOT!) doing anything remotely significant about a problem they all know they have (much less the puppy farmers or commercial breeders, and the clubs have no moral high ground above the average puppy farmer/miller on this issue because they continue to do just enough == donate to a little research here, mention the issue ion a website there, hold auscultation days to which almost no one brings older cavaliers that might not pass) to be able to claim they are doing something.
Because we here care about giving this breed a real future, and because this breed is now increasingly at risk as almost all international breed clubs stand more or less, idly by (the Scandinavian clubs are miles ahead in actually doing something!!) we campaign strongly here on health and have fundraising projects for Rupert's Fund, Margaret Carter's Cavalier Collection scheme and other projects because we think it is better to contribute directly to researchers, and to directly enable breeders to get scans paid for, through Rupert's Fund.
There are few breeds that do not have their own pedigree issues so if one opts for a pedigree dog rather than a Heinz 57, then increased health problems, statistically, are part of the choice. Unfortunately for cavaliers, the problems they have are in two cases, potentially very serious and costly to diagnose and manage, endemic across the breed internationally, and it is pretty much impossible not to end up dealing at some point, to some degree or another, with one or the other or both MVD/CMSM.
The best thing anyone can do for the breed is work with a breeder who is serious about health, who works with the protocols, properly tests, and isn't giving la la land excuses.
I think at this point, breeders have to question the ethics of breeding cavaliers if they are not doing MRIs and using cavalier studs from breeders who also do MRIs. The statistics are there for the likelihood of offspring MRIing with SM -- very high. Over time, the Estimated Breeding Values project in the UK will reduce the need to actually MRI because likelihood of a dog having SM will be estimatable. But right now and in the absence of a DNA test, breeders need to MRI. Cost is not a morally adequate excuse. Breeders and clubs in places that still do not have nationwide low cost schemes need to unite and work to get them. Neurologists and scanning centres need to see there is actually a wide demand, from breeders and their clubs, for this to be available.
ONE puppy sale will fund two or more (often as many as three to four) MRI scans at existing low cost scanning centres in the US, By the way. Just to give some cost perspective.