QUINCY, MA -- For middle-aged cats, the most common cause of death might be heart disease. Dr. John Rush, veterinary cardiologist at Cummings School of Veterinary Medicine, Tufts University, focused on this troubling issue when he spoke to 130 veterinary professionals and cat breeders at the 34th Winn Feline Foundation Annual Symposium June 28.
Winn Feline Foundation is a non-profit that funds cat health studies. One special interest is funding research on feline hypertrophic cardiomyopathy (HCM), the most common form of heart disease in cats. HCM is so prevalent that in 2002, the foundation created a fund specifically targeted to raise money for HCM studies.
Winn's funding allowed geneticist Dr. Kate Meurs to identify gene defects in two breeds, the Ragdoll and Maine Coon. With a simple cheek swab, an inexpensive test can determine if the defect for HCM exists, and breeders may respond accordingly. Rush noted in his presentation that while the genetic test is imperfect, it really can help to guide breeding programs.
Another recently developed tool is a test to help cat owners concerned about HCM, and to lend a paw to veterinarians seeking a diagnosis. The proBNP test, or Cardiopet test, was developed for cats (and another test for dogs) by IDEXX Laboratories. Cardiopet is an inexpensive blood test.
A heart murmur or rapid heartbeat are two signs of potential HCM, although many cats have heart murmurs but no heart disease. Rapid heartbeats are common among all nervous kitties at a veterinary clinic and not necessarily indicative of HCM. Also, even if there are no signs, cardiologists know some breeds seem more predisposed to HCM, and so are individuals with a known family history of the disease.
Previous to the Cardiopet, the next step for cats with murmurs, rapid heartbeats and a family history of HCM might have been an expensive echocardiogram. Some owners refuse this test due to the cost and concerns that the odds of disease may low and don't justify the cost.
If Cardiopet results show heart disease is possible, an echo remains the "gold standard" and offers a veterinary cardiologist a picture to see just how diseased the cat's heart is. If negative, the results may put the cat owner at ease.
The Cardiopet test is also used to distinguish between respiratory disease and heart disease, since in cats the symptoms may be similar. If a cat turns out to have respiratory disease (perhaps due to heartworm), that expensive echocardiogram is necessary, and treatment is different than for cats with HCM.
At the symposium, Rush explained that HCM is an abnormal thickening of the heart, which makes the heart work harder. Some cats with HCM live perfectly normal lives, and as far as anyone can tell they're not suffering. However, many cats with HCM do become very sick, ultimately suffering heart failure or suffering repeated episodes of painful Arterial Thromboembolism, which typically renders a cat's back legs useless. Once this happens, it will like recur until treatment is no longer effective or owners simply run out of money for treatment.
Sadly, many cats with HCM simply drop dead; HCM is the No. 1 cause of sudden death in cats.
Drugs that have been used for years may slow the progression of HCM, although some experts are skeptical about the effectiveness of any current drug therapy. Winn Feline Foundation has supported funding for studies on the effectiveness of new drugs, but, so far, no pill has turned out to be a magic bullet.
Learn more about heart disease in cats and the Ricky Fund at http://www.winnfelinehealth.org. You can hear the Winn Feline Symposium (free) at http://www.petworldradio.net.
(Steve Dale welcomes questions/comments from readers. Although he can't answer all of them individually, he'll answer those of general interest in his column Send e-mail to PETWORLD(at)STEVE DALE.TV. Include your name, city and state. Steve's website is http://www.stevedalepetworld.com; he also hosts the nationally syndicated "Steve Dale's Pet World" and "The Pet Minute." He's also a contributing editor to USA Weekend.)