- Heart disease in cats, like many other feline diseases, often remains hidden, and research shows that many apparently healthy cats have heart problems.
- A recent study shows that screening ultrasounds performed by trained general practice veterinarians can help diagnose the vast majority of significant heart disease in cats.
- This technique could be invaluable in finding heart disease in asymptomatic cats before it becomes a crisis.
- Hypertrophic cardiomyopathy accounts for 80% of feline heart problems.
- Steps you can take to help prevent heart disease in your cat include feeding a nutritionally optimal, species-appropriate diet and supplementing with CoQ10 in the form of ubiquinol.
About 10% to 15% of cats have some type of heart disease,1 and as with all illnesses in kitties, it often remains hidden until it becomes a crisis.
“Often, cats with heart disease show no signs that something is wrong with their heart, and thus the signs that they’re getting in trouble come on very, very suddenly,” explains veterinary cardiologist John Rush of Tufts University’s Cummings School of Veterinary Medicine. “They’re fine one moment, and they’re in a lot of pain or have marked difficulty breathing the next moment.”2
Hiding health problems comes naturally to cats, because in the wild, showing weakness makes them more attractive to predators.
Diagnosing Heart Disease in Cats Can Be Challenging
A heart murmur isn’t an accurate indicator of the presence of feline heart disease, because sometimes kitties with heart disease have a murmur and sometimes, they don’t. In addition, cats can have a heart murmur but no heart disease.
When presented with a cat with suspected heart problems, many veterinarians refer the owner to a veterinary cardiologist, who uses ultrasound imaging to view the heart and diagnose disease. Sometimes kitties require light sedation to undergo an echocardiogram, and cardiac evaluations can run several hundred dollars.
Fortunately, in recent years ultrasound machines have gotten smaller and less expensive, making them more accessible to general practice veterinarians. In 2016, veterinary researchers from Cummings School of Veterinary Medicine, including Dr. Rush, wondered if an initial brief ultrasound exam of the heart in asymptomatic cats could potentially find heart disease before it reached the crisis stage.
With funding from the Morris Animal Foundation, they launched a study to teach primary care veterinarians to use ultrasound to screen for heart disease in cats. The results, recently published in the Journal of Veterinary Internal Medicine,3 were encouraging.
Researchers Went on the Road to Teach Local Veterinarians How to Perform a ‘Two-Minute Echo’ on Cats With Suspected Heart Disease
The Cummings research team nicknamed their study the “cat cardiology roadshow,” because they traveled around New England teaching veterinarians how to use an ultrasound machine and how to view the left atrium and left ventricle of cats’ hearts. Simultaneously, a team from the University of Pennsylvania School of Veterinary Medicine took a similar roadshow around the Philadelphia area.
“When cats have heart disease, they often get hypertrophic cardiomyopathy — a problem with the heart muscle,” says study co-author Elizabeth Rozanski, a critical care veterinarian at Foster Hospital for Small Animals at Cummings.
“The first thing that happens is the left ventricle, which pumps blood to the body, gets thicker. Over time it doesn’t relax as well, so it can’t fill as effectively with blood, and the holding chamber (the left atrium) starts to get bigger. This happens over a long length of time.”4
The roadshow researchers taught the veterinarians to recognize when either of the walls of the left ventricle were thicker than they should be, and whether the left atrium was enlarged. Rush dubbed the screening ultrasound the “two-minute echo” because it takes just a couple of minutes and is also gentle on the cat.
The ‘Two-Minute Echo’ Helps to Identify the Vast Majority of Asymptomatic Cats With Moderate to Severe Heart Disease
After the training, veterinarians were able to identify the vast majority of asymptomatic kitties with significant heart disease.
“The vast majority of cats with moderate to severe heart disease were found by veterinarians in practice after completing this training,” Rush said. “The cats with moderate to severe heart disease, who are still showing no outward signs of cardiac disease, are clearly the ones we want to find, so they can get a complete cardiac evaluation and start on medications.”5
Unfortunately, the two-minute echo procedure isn’t as successful in helping to identify cats with mild heart disease. However, the veterinarians who were trained in the procedure told the researchers they planned to continue to screen cats for heart disease using the two-minute echo procedure. Rush expects the technology to continue to get smaller and cheaper, making it even more accessible to veterinarians who see its value.
Studies Show Many Apparently Healthy Cats Have Heart Problems
Heart disease has traditionally been considered more common in dogs that cats, but it may actually be more prevalent in kitties than we thought. A prospective study of 103 healthy pet cats conducted in 2004 at Angell Memorial Animal Hospital in Boston concluded:
“… heart murmurs were detectable in a large proportion of overtly healthy cats and that many murmurs appear to be caused by structural heart disease that is in a clinically latent state.”6
Of the 103 cats in the study, 22 (21%) had detectable heart murmurs. Of the 22 cats with heart murmurs, echocardiography was performed on 7, 6 of which turned out to have heart disease. Thirteen kitties were examined more than once for the study, and 3 of them developed heart murmurs during the course of the study.
In 2009, a cross-sectional study of another 103 “overtly” healthy privately-owned cats was conducted at the Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute in Blacksburg. The objective was to determine the prevalence of cardiomyopathy in healthy cats, as well as the relationship between cardiomyopathy and heart murmurs.7
A heart murmur was detected in 16 cats (15.5%), 5 of which had cardiomyopathy (a disease of the heart muscle). Cardiomyopathy was also identified in another 16 cats, 15 of which had hypertrophic cardiomyopathy, the most common form of feline heart disease. The researchers concluded that:
- Cardiomyopathy is common in healthy cats
- In apparently healthy cats, a heart murmur isn’t a reliable indicator of the presence of cardiomyopathy
However, in a 2011 study of a smaller sampling of 32 apparently healthy cats with heart murmurs, heart disease was detected in over half (53%). Those researchers concluded that heart murmurs detected in routine physical exams of healthy cats warrant further investigation.8
If you have a feline companion, it’s important to know what types of heart problems she may encounter. Sometimes the signs are obvious to a trained eye (your veterinarian). But often a serious heart disorder in a cat can remain hidden for years before it suddenly expresses itself, which is why screening ultrasounds like the “two-minute echo” can be invaluable.
Hypertrophic Cardiomyopathy — The Most Common Heart Condition in Cats
The heart condition most commonly seen in felines is hypertrophic cardiomyopathy (HCM), and it accounts for 80% of feline heart problems.9 Maine Coons and Ragdolls are genetically predisposed to HCM, and there’s a genetic test available for these two breeds.
The problem is also seen in the Persian, other oriental breeds, and American shorthairs, but it can occur in any cat. Kitties usually develop the condition when they reach middle age, but it can occur at any age.
Two other types of cardiomyopathy — restrictive cardiomyopathy and dilated cardiomyopathy — are much less common in kitties. However, dilated cardiomyopathy (DCM) was quite common before a link was discovered between taurine deficiency and DCM around 1980.
Now that taurine is routinely added to commercial cat food, the disease is seen far less in kitties, and well-formulated raw food diets rich in organ and muscle meats contain abundant, naturally occurring taurine.
Symptoms of feline HCM vary and depend to some extent on the severity of the disease. Cats with mild disease don't always have symptoms. But a kitty with significant disease will typically show obvious signs of a problem.
The challenge for pet parents is that cats are masters at disguising illness, so until the condition is severe, even a very sick cat may have no symptoms, or very mild symptoms that are nonspecific and don't seem to point to heart disease, such as a tendency to hide more, eat less, or be generally lethargic.
In cats with obvious symptoms, there can be respiratory distress caused by congestive heart failure, or leg paralysis due to a blood clot.
Cats suffering congestive heart failure tend to breathe through an open mouth, and they sometimes pant. You should watch for breathing difficulties during exertion. Some kitties with HCM and congestive heart failure have a hard time walking any distance without stopping to rest.
Steps You Can Take to Help Protect Your Cat's Heart Health
Heart murmurs, arrhythmias, or gallops detected in routine physical exams of healthy cats certainly warrant further investigation. If your veterinarian doesn’t have access to ultrasound as a diagnostic tool, I strongly encourage you to ask him or her to run a proBNP blood test on your kitty. This test can give you peace of mind that your cat has no early signs of heart disease, or it can alert you to a problem so that you can take steps to proactively manage her heart health.
In addition, keep your pet lean and fit by feeding a nutritionally optimal, species-appropriate diet that meets her nutritional requirements for animal protein (amino acids), healthy fats and coenzyme Q10. I believe the unnecessary carbohydrates found in most processed cat foods offset the amount of protein cats need, making carbs a significant nutritional contributing factor to feline heart disease.
Also, the high temperatures the food is processed at inactivates the delicate fatty acids, so even though the label says it contains the correct amount of essential fatty acids to maintain good cardiovascular health, they've been inactivated through the manufacturing process.
The amount of taurine, carnitine and CoQ10 found naturally in unprocessed meat is critically important to your cat’s heart health. These vital nutrients are not found in adequate quantities in most dry foods and processing further diminishes their bioavailability. This is another reason I recommend starch-free foods (no grains or potatoes) for cats.
If you feed dry or canned food, I recommend supplementing your pet's diet with coenzyme Q10 in the form of ubiquinol, as well as additional marine sources of omega-3 fatty acids (krill oil), especially if you have a cat that may be predisposed to cardiovascular disease.
Supplying your pet with extra CoQ10 (the reduced form) can insure she has the quantity her body needs to maintain a healthy heart muscle.
