10 Signs of Heart Disease in Dogs and Cats

It’s no secret that we all love our pets and want to make sure they are in the best of health. So when it comes to heart disease in cats and dogs, we understand how it can be a scary thing to pet owners. Luckily, understanding the warning signs can save their lives.

Signs of heart disease are usually easier to see in dogs and less detectable in cats. Regardless, if your dog or cat has recently fainted, has a persistent cough, difficulty breathing, or noticeable abdominal swelling, call your vet right away.

Speaking of the vet, make sure you’re taking your cat or dog to their primary care veterinarian for checkups at least once a year. A regular checkup could easily spot the early warning signs of heart disease in cats or dogs.

Preventive, proactive care is the best kind of care we can offer our pets. Educating yourself with helpful resources like this page on our website will also help to ensure they live long, healthy, and happy lives.


Symptoms of Heart Disease

While there are several heart diseases that your cat or dog can contract or develop, the symptoms are all usually very similar. This is because heart disease doesn’t necessarily mean one specific type of condition but encompasses a wide range of heart-related problems that can affect your cat or dog. If your pet is experiencing any of the following symptoms, we suggest taking them to your veterinarian straight away.

1. Persistent Cough

When we say a persistent cough, we don’t mean just one or two days of coughing. Like people, dogs and cats can cough for reasons related to allergies, asthma, or even sinus problems. But if your pet has a cough that lasts for at least one or two weeks, it could be an indication of heart disease. This is because when your pet has a heart condition, the heart likely isn’t pumping enough blood, which can cause fluid backup in the lungs, resulting in a cough.

2. Difficulty Breathing

While fluid build-up in the lungs usually leads to coughing, it can also cause breathing difficulties in your pet. These symptoms tend to be more noticeable in dogs, but you may also notice them in cats. Your pet may stand around with their mouth hanging open to try and breathe, and they may even seem distressed and resistant to laying down to relax.

3. Fainting/Collapsing

Seeing your pet collapse can be alarming—and for a good reason. Heart disease can cause your animal’s legs to give out or for them to lose consciousness completely. There are many reasons why your cat or dog could be fainting or collapsing, but it’s best to get them to a vet immediately to understand the cause of the issue.

4. Abdominal Swelling/Distention

Most commonly, abdominal swelling tends to happen when your cat or dog has intestinal parasites, a stomach obstruction, or a tumor. Unfortunately, this can also sometimes be a sign of heart disease in your pet. Due to fluid build-up in their abdomen from the heart condition, your cat or dog’s stomach will swell, making them appear pot-bellied.

5. Less Tolerant of Exercise

Even if you’re not a fan of exercise, you should be making sure your pet gets enough of it to stay healthy. One of the less obvious signs of heart disease may be your pet’s unwillingness to exercise. It’s normal if they’re panting or breathing heavily after a vigorous round of play, but if it takes them a long time to recover or they don’t want to play at all, this could be a sign that your pet needs a checkup.

6. Heart Murmur

Just like humans, dogs and cats with heart disease can also develop something called a heart murmur. Typically when you listen to the sound of a heartbeat, you know that a “ba-dum, ba-dum” rhythm is the sound of a healthy heart. If there’s a “whooshing” sound that’s present, though, it means that there’s a heart murmur. Fortunately, as long as the size or reason for the murmur isn’t too severe, humans and pets alike can live healthy and normal lives with one.

7. Change in Heart Rate

Most of the time, you won’t notice a change in your pet’s heart rate without the help of a professional, but it can be an early sign of heart disease. For instance, a cat’s heart rate usually ranges between 140 and 220 beats per minute, while a dog’s heart will beat anywhere from 60 to 140 times per minute. If their heart rate is outside of that normal range, it may indicate heart disease.

8. Change in Body Weight

As humans, we usually see weight loss as a good thing, but your cat or dog’s rapid weight loss does not carry the same positive meaning. When your pet has heart disease and is losing a lot of weight quickly, it’s because there is a hormone-like substance produced at high levels during heart failure. This results in muscle and weight loss in your pet.

9. Restlessness or Hiding

Typically it’s easier to tell when your dog isn’t feeling well as opposed to your cat. Your dog will usually become visibly distressed when they’re in pain or feeling sick, or even hide from you. Cats, on the other hand, are very good about hiding when they’re ill. Typically heart disease starts appearing in cats between the ages of 4 and 6 years (but it can occur at any time), so make sure you pay close attention if you notice your cat being particularly more aloof than usual.

10. Loss of Appetite

If your cat or dog unexpectedly stops eating, it’s a good sign they’re not feeling well, but it could also be a sign of heart problems. Sometimes your pet may not eat for many hours, and that’s okay. However, if they go more than a day without food, this could cause problems, especially in cats. If cats don’t eat for an extended period, organs other than the heart can start to fail, so it’s essential to make sure they’re getting enough nutrients. A sign that your cat or dog isn’t feeling well is if they refuse to eat even one of their favorite treats.

Six Different Types of Heart Disease in Pets

As we mentioned earlier, “heart disease” is a catch-all term for many different heart conditions. So if you’re wondering what exactly those conditions are, keep reading as we highlight some of the most common heart diseases that we treat here at CVCA.

Valvular Disease

Valvular disease is a heart condition that can affect both cats and dogs. It appears when the valves within your pet’s heart are abnormal, which causes leakage and—over time—an enlarged heart. This disease typically affects 10% of dogs from ages 5 to 8, 25% of dogs ages 9 to 12, and 30-35% of dogs 13 and over. Unfortunately, it’s often an early sign of heart failure.

Myocardial Disease

When your cat or dog’s heart muscles become weak or thick, we call this Myocardial disease. This heart condition and weakening of the muscles makes it so that the heart is less efficient at pumping blood. While the disease can’t be reversed, it can be managed with proper nutrition and exercise.


Remember when we talked about the typical “ba-dum, ba-dum” that you usually hear with heartbeats? When that sound isn’t normal, it means the valves of the heart aren’t functioning correctly. An arrhythmia in dogs or cats is usually caused by other heart conditions or even old age.

Pericardial Disease

Did you know that there is a sac around the heart called the pericardial sac? It’s there to provide lubrication for the heart and to protect it when it moves around. It is present in both humans and our pets. When that sac becomes filled with too much fluid, we call that pericardial disease.

Heartworm Disease

Parasites are always a problem for pets and can be a genuine danger if left untreated. Spread through mosquito bites, heartworms can be deadly to your pets by damaging their heart, lungs, and other organs. It’s why our vets (and most others) recommend heartworm treatment when you come into the office!

Congenital Disease

Sometimes our pets are born with quirks like extra toes or a missing tail, but they can also sometimes be born with abnormalities that we can’t see. With congenital heart disease, your cat or dog was born with a malformed heart that they possibly inherited from one of their parents. And while it may not always be a problem, as your pet ages, it can lead to many other heart conditions.

Want To Schedule an Appointment for Your Pet?

Schedule an appointment with one of our veterinarians today!

If you’re worried about heart disease in your dog or cat, get in touch with our board-certified cardiologists here at CVCA. We love your pets just like our own and want them to live out the happiest and healthiest of lives. Our expertise and top of the line echocardiography equipment ensure an accurate diagnosis and the best outcome for your pet.