Dogs and Heart Disease: An Overview


Dr. Ruth MacPete explains canine heart disease. For more from Dr. MacPete, find her on Facebook or at!

“Dogs get heart disease?” The surprised question from a human doctor friend of mine still echoes in my ears. The answer, of course, is yes! Dogs get heart disease, just like their human companions. In fact, it is estimated that 7.8 million dogs in the United States have heart disease. That means approximately 10% of all dogs in the United States have heart disease. Despite these numbers, many people, even those in the medical field, are unaware that their dog may be at risk for heart disease.

Heart disease in dogs is almost as common as it is in humans, but unlike people, smoking and a fatty diet are not risk factors. The most common form of heart disease in dogs is valvular disease, which primarily affects small breed dogs over 5 years of age and makes up 70-75% of heart disease in dogs. Heartworm disease causes 13% of heart disease even though it is entirely preventable. Myocardial disease, such as dilated cardiomyopathy, makes up 8% of heart disease and primarily affects large breed dogs of all ages.

What are the signs of heart disease in dogs?
The clinical signs of heart disease depend on the type of disease and severity. It is important to note that early on there may be no symptoms at all. As heart disease progresses to congestive heart failure, which occurs when the heart is unable to meet the body’s demands, a dog may develop more obvious symptoms such as fatigue, reduced willingness to walk or exercise, difficulty breathing, loss of appetite, weight loss, a distended abdomen, trouble sleeping or coughing. If you see any of these symptoms, you should have your pet seen by a veterinarian immediately.

How do you know if your dog has heart disease?
Since early heart disease is asymptomatic, it is best to take your dog to the veterinarian every year to screen for heart disease. Your veterinarian will listen to your pet’s heart for abnormal sounds like murmurs or irregular rhythms and will look for other subtle signs of heart disease. If your veterinarian suspects heart disease, they may measure blood pressure or suggest additional tests like x-rays, cardiac ultrasounds, or ECGs to confirm the diagnosis and determine the cause so that treatment can be started.

What can you do if your dog develops heart failure?
While there is no cure for congestive heart failure (CHF), fortunately there are medications available to help the heart work better. The Quality of Life and Extension of Survival Time trial (QUEST), the largest clinical trial studying of dogs with CHF, reported that dogs treated with pimobendan lived longer and enjoyed a higher quality of life compared to dogs treated with conventional therapy. Speak with your veterinarian or a veterinary cardiologist to determine which medications your dog will need depending on the type and severity of their heart disease.

What can you do to prevent heart disease in dogs?
Unfortunately, although diet and exercise are important for preventing other important diseases like obesity, diabetes and arthritis, they have not been found to prevent acquired heart disease in dogs. In fact, most forms of heart disease in dogs cannot be prevented except for one notable exception: heartworm disease. It is sad to think that 13% of all dogs in the US with heart disease have a disease that is entirely preventable. Keeping your pet on year-round heartworm preventatives can protect your pet from getting this deadly disease. Although heartworm disease can be treated, it is much easier to prevent it in the first place. In addition to preventing heartworm disease, these medications are also effective against other internal parasites and can protect your human family from zoonotic infections. Protecting your pet from heartworm disease not only makes sense, it’s also really simple!

Although heart disease in dogs cannot be prevented with the exception of heartworm disease, the goal is early diagnosis and treatment. Routine visits to the veterinarian can help catch heart disease while it is still asymptomatic. During these visits, your veterinarian will listen to your dog’s heart for murmurs or irregular rhythms and look for early signs of heart disease. Additional tests like x-rays, cardiac ultrasounds or ECGs may be ordered by your veterinarian to establish the diagnosis and determine the cause in order to start the right treatment. Starting treatment earlier can improve quality of life and extend life expectancy.

Take home message:
The take home message is that heart disease is almost as common in dogs as in people. Even though most forms cannot be prevented, heart disease caused by heartworms can easily be avoided with year-round preventatives. Likewise, in dogs who have developed heart failure, quality of life and life expectancy can be improved with early diagnosis and treatment. I recommend taking your dog to your veterinarian for a routine check-up to screen for heart disease at least annually and every 6 months for older pets. To learn more about heart disease in dogs, ask your veterinarian.