How to Recognize Heart Disease in Dogs and Cats

PetMD Editorial
By PetMD Editorial on Aug. 7, 2018
How to Recognize Heart Disease in Dogs and Cats

Heart disease in dogs and cats can be a tough diagnosis for vets to make and for pet owners to receive. Depending on the specifics of the condition, your vet may not be able to do much, but that’s not always the case.

While there aren’t any scientifically proven ways to prevent heart disease in cats and dogs, Dr. Bill Tyrrell, veterinary cardiologist and founding partner of CVCA, Cardiac Care for Pets, says that the best thing you can do for your pet is to identify the symptoms early.

This ensures that your veterinarian has time to diagnose and create a treatment plan for your pet that can help them maintain a good quality of life through their golden years.

So, how do you recognize heart disease in dogs and cats? And what happens next?

What Are the Symptoms of Heart Disease in Dogs?

Symptoms of congenital heart diseases, according to Dr. Michael Aherne, clinical associate professor of cardiology at the University of Florida College of Veterinary Medicine, generally appear in younger dogs who are born with the condition. Acquired heart diseases, meanwhile, are likelier to show up as the dog ages.

In either case, Dr. Tyrrell says that slowing down is one of the first noticeable symptoms of heart disease in dogs. “If the dog is an active one, owners will notice a slow down or that their dog is sitting down on the walk,” Dr. Tyrrell says. “Owners tend to attribute that to age, arthritis or orthopedic discomfort, but lethargy is a very common symptom of cardiac diseases.”

As dog heart disease enters into the heart failure stages, Dr. Tyrrell says that most dogs will begin to cough. “Some will see an increase in their resting respiratory rate or effort, but most cough along with an increase in their respiratory rate and effort.”

If the dog’s breed is predisposed to certain heart disease, Dr. Tyrrell recommends that owners monitor the dog’s resting breathing rate at home. When your dog is lying on the floor, count the amount of times his chest rises in a minute.

Dr. Tyrrell says that anything less than 35 is normal. Over time, if you start to see a progressive increase in the rate or effort, you should make an appointment with your vet or a veterinary cardiologist.

What Are the Symptoms of Heart Disease in Cats?

Dr. Aherne says that cat owners may have trouble noticing when their pet’s normal behavior is symptomatic of something until it progresses to congestive heart failure. “It can be hard to tell if the cat has slowed down because of heart disease, or if he’s simply exhibiting normal laziness,” he says.

Dr. Tyrrell says that cat heart disease symptoms include increased reclusiveness, loss of appetite and respiratory difficulty, though he notes that very few cats cough when they have heart disease, even in its advanced stages.

Purring makes it difficult to count a respiratory rate in cats. You can try counting the breaths per minute while your kitty is sleeping. The normal respiratory rate can be anything less than 50 breaths per minute.

Are Certain Dog Breeds More Likely to Develop Heart Disease?

Simply put, the answer is yes. Dr. Tyrrell says that most of what veterinary cardiologists deal with is genetic, which makes observing the progression of heart disease from early in the dog’s life—and, in turn, treatment of it—a little more manageable.

Large breed dogs, including Great Danes, Dobermans, and Boxers, are more likely to be affected by dilated cardiomyopathy. This type of heart disease in dogs involves enlargement of the muscle, which decreases its ability to pump blood.

Dr. Tyrrell says that the Cavalier King Charles Spaniel is particularly susceptible to heart murmurs. “Fifty percent will have developed a murmur by age five,” he says, “and 100 percent will have one by age 10.”

Poodles, Pomeranians, Schnauzers—all are predisposed to valve disease, Dr. Tyrrell says, but when it comes to breeds that are less likely to develop any type of heart disease, you can possibly look to some of the Terriers—Scotties, Westies, Cairns and others. These breeds don’t tend to be affected with heart disease as much as other small breeds of dogs, he says.

Are Certain Cats More Likely to Get Heart Disease?

Most people don’t have purebred cats, Dr. Tyrrell says, so it can be more challenging to make sweeping generalizations. However, Maine Coons, Rag Dolls, Bengals, Sphinxes and American Short Hair breeds tend to be most affected with hypertrophic cardiomyopathy from a genetic standpoint.

That said, researchers at North Carolina State University found genes that code for hypertrophic cardiomyopathy in Ragdolls and Maine Coons, among others breeds. This disease, the most commonly diagnosed cardiac condition in cats, causes the cat’s left ventricle to thicken, making the pumping of blood to the aorta more challenging.

Dr. Tyrrell notes that there’s still a long way to go before the scientific community has a handle on feline genetics and heart disease in cats. “With people, we know of more than 600 genes that code for this disease,” he says. “With cats, we have one.”

What Tests Are Done to Diagnose Heart Disease in Dogs and Cats?

Dr. Aherne says a thorough medical history is almost enough to make a diagnosis, but for the most accurate pet health information, vets and veterinary cardiologists will start with a physical exam, during which they listen closely to the lungs.

Then, an echocardiogram and/or X-ray of the chest are performed to get the size of the heart and to take a look at the way the valves are working. “From there, we can make a definitive diagnosis and give a prognosis to the owner,” Dr. Aherne says.

Dr. Tyrrell says that one of the biggest things to keep in mind is what he calls the “triad of care.” According to him, the best way to diagnose and treat cat and dog heart disease is with coordination between the owner of the pet, the primary care vet and the specialist.

“I encourage people, if they have concerns—regardless of cardiac health—to talk to their primary care vet. Then they’ll make a referral to the cardiologist if necessary,” says Dr. Tyrell. “Working together between these three people is ultimately what allows pets to live longer, happier lives.”

How Can Pet Owners Help a Pet With Heart Disease?

Early detection—before the dog goes into heart failure—is the best way to manage heart disease in dogs and cats. A landmark study known as the “EPIC Trial,” found that a prescription heart medicine for dogs called Vetmedin (pimobendan) helped extend the pre-failure period by an average of 15 months. As a result, it also extended the lives of the dogs who took the drug significantly compared to those who took a placebo.

“A lot of dogs we catch early can live three to five years before failure sets in,” Dr. Tyrrell says. “After that, the diagnosis is highly variable. It can be dependent on breed or whether the dog develops arrhythmias. Some only live a few months. Some may be a year and a half or two after heart failure is diagnosed.”

On the feline side, Dr. Tyrrell says there isn’t the same study that shows early intervention can delay the onset of heart failure. “We certainly believe that to be the case, and we’re working aggressively to find the right answer,” he says. “Early diagnosis and intervention with medications can help a cat significantly, but prognosis can be quite variable.”

By John Gilpatrick

Featured Image: Hollysdogs/

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