Heart Disease in Dogs: Types, Symptoms, Treatment & Prevention

Reviewed by Dr. Fiona Lee

Heart disease in dogs is more common than many pet parents realize. In fact, about 1 in 10 dogs will develop some form of heart disease in their lifetime.¹ While the idea of your furry family member having heart problems may sound scary, early detection and treatment can make a world of difference in your pup's outcome. Understanding the basics of canine heart health can help you spot concerns early and take steps to help.

What Is Heart Disease in Dogs?

Just like in humans, heart disease in dogs affects the heart's ability to pump blood efficiently. This can lead to poor circulation, fluid buildup in the lungs, fatigue or heart failure. The risk of heart disease in dogs tends to increase with age.²

There are two main categories:

• Congenital: Present at birth and often involves structural defects, like a poorly formed valve or a hole in the heart.
• Acquired: More common, particularly in older dogs. Develops with age.

Types of Heart Disease in Dogs

Below is an overview of some common types of heart disease in dogs.

• Degenerative mitral valve disease (DMVD): This is the most common type. The mitral valve gradually thickens with age, which can cause blood to leak back into the chamber it just came from, potentially leading to an enlarged heart and congestive heart failure. Many smaller breeds are more susceptible, like Cavalier King Charles Spaniels (nearly all will develop it), Dachshunds, Toy Poodles and Chihuahuas.²
• Dilated cardiomyopathy (DCM): The heart muscles weaken and thin, reducing the amount of blood pumped, putting your dog at risk of heart failure. It's more common in large or giant breeds.¹ Research suggests that grain-free diets (particularly ones with pulse plants, such as peas, or with potatoes) might increase the risk.³
• Congenital heart defects: These are conditions your dog is born with, such as patent ductus arteriosus (PDA), septal defects or malformed heart valves. Some breeds, like the Poodle, Corgi, Yorkshire Terrier and Bichon Frise, are more susceptible. Diagnosis might only happen if a veterinarian detects a heart murmur at a puppy visit.²
• Heartworm disease: Caused by parasitic worms transmitted through mosquito bites. The best treatment is prevention through a monthly medicine, but veterinary treatments are available for infected dogs.²
• Arrhythmia: Irregular heartbeats can affect dogs of any age or breed, but some brachycephalic breeds, like Bulldogs, may be at higher risk. Causes range from genetics to toxins, stress, infections, anemia, age and more.⁴ The most common cause is heart disease, especially DCM.
• Pericardial disease: This involves fluid building up around the pericardium (a thin sac surrounding the heart). It often develops in response to another condition, such as cancer or inflammation. It's more common in medium dog breeds and large dog breeds, like German Shepherds. However, one of the tumors (chemodectomas) that can cause it is more common in short-nosed dogs like Bulldogs.²
• Congestive heart failure: This occurs when a dog's heart can't pump blood efficiently, so fluid builds up in the lungs and/or abdomen. This is not the same as heart disease; it's a result of heart disease. Not all dogs with heart disease are in congestive heart failure.⁵

Can Dogs Have Heart Attacks?

In dogs, true heart attacks (myocardial infarctions) from coronary disease are exceedingly rare.⁶

However, dogs can experience acute cardiac events that lead to sudden death, which can appear similar even though the cause is different. For example, a dog may have ventricular fibrillation (where the lower heart chambers don't pump blood well), which can lead to sudden cardiac death.⁶

If your dog collapses or has a combination of symptoms like vomiting, increased heart rate, limping, lethargy, trouble walking, going rigid, seizures, head tilting or confusion, get to a veterinarian right away.⁶

Signs of Heart Disease in Dogs

Heart disease can be sneaky. Early symptoms may appear vague, but if you pay close attention, you might be able to get your dog treatment before the condition gets worse.

Early warning signs include:⁷

• Mild coughing that lasts more than a few days
• Breathing faster than normal
• Stretching their neck while sitting (indicates breathing issues)
• Standing with legs far apart
• Getting tired faster during walks
• Sleeping more
• Decreased appetite
• Isolating
• Reluctance to play
• Trouble settling down at night⁸

Moderate symptoms may include:⁹

• Fatigue and shortness of breath even during short walks
• Frequent coughing and wheezing
• Labored or rapid breathing
• Losing weight and muscle⁸
• Gums or tongue developing a blue-gray color⁸

Severe symptoms that indicate an emergency include:²

• Fainting (syncope) or sudden collapse
• Swollen abdomen
• Extreme difficulty breathing
• Seizures¹⁰

You should see a veterinarian if you notice any of these symptoms. If your dog has severe signs, go to an emergency veterinarian ASAP.

How Is Heart Disease Diagnosed in Dogs?

If you suspect your dog has symptoms of heart disease, talk to your veterinarian. They will ask for your dog's history and do a physical exam, including using a stethoscope to listen to the heart. Your veterinarian may also recommend diagnostic tests such as:¹⁰

• Chest X-rays: To detect heart enlargement or fluid in the lungs.
• Echocardiography: An ultrasound of the heart.
• Electrocardiogram (ECG): To identify arrhythmia.
• Cardiac catheterization: Placing a thin tube in the heart, aorta or pulmonary artery. While it can be used for diagnostics, it's more commonly used to repair heart defects.
• Blood tests: Looking for concurrent diseases and ensuring the patient is a good candidate for heart medications if prescribed.

Treatment Options for Heart Disease in Dogs

While heart disease usually isn't curable (with the exception of some congenital defects that can be surgically corrected), it can be managed with the right care. Your veterinarian might recommend various treatments, such as:

• Medications: Diuretics or ACE inhibitors can help heart function.¹ Pimobendan can delay congestive heart failure in dogs with mitral valve disease.² Note that some dogs may need their heart medications adjusted if kidney function is impacted.¹⁰
• Dietary changes: Your veterinarian might ask you to reduce your dog's sodium intake.² Or they may want you to switch to a food designed for heart health.⁶ And if your dog was on grain-free food, your veterinarian will want you to switch to a grain-inclusive one.
• Supplements: Some veterinarians may recommend omega-3 fatty acids or taurine if blood tests show a deficiency.² Taurine is especially likely to be recommended if your dog was on a grain-free food. Carnitine and antioxidants like coenzyme Q10 and vitamin E may also be recommended.⁹
• Weight management: You may need to monitor your dog's weight closely, ensuring they don't become overweight or underweight.¹
• Exercise and lifestyle adjustments: You may be asked to give your dog moderate exercise, like light walks, while making sure not to push your pup beyond what they can easily do. In cases of severe illness, you may need to minimize your dog's exercise.² Of course, muting a dog's excitement to keep their activity levels lower is easier said than done. Try to avoid triggers that overexcite them, like seeing unfamiliar dogs. But keep up the mental stimulation, like treat puzzles.¹¹
• Surgical and other advanced treatments: In more severe cases, your dog might need surgery. For example, dogs with pericardial effusion may need the fluid drained.²

Preventing Heart Disease in Dogs

While you can't prevent all types of heart disease, you can help reduce your dog's risk:

• Annual veterinarian appointments: This can help with early detection of heart murmurs or irregular heartbeats.³
• Heart screening: Breeds at higher risk might need heart disease screening. Ask your veterinarian.¹
• Heartworm preventive: Keep up with your dog's monthly preventive.³
• Healthy weight: Proper nutrition—and possibly avoiding a grain-free diet—can help, along with portion control to ensure your pup maintains a healthy weight.⁹
• Regular exercise: Ask your veterinarian what is recommended for your dog's age, breed and health. Regular walks can help minimize risk.⁷

Pets Best Is Here To Help

The idea of your dog having heart disease may sound overwhelming, but with early detection and treatment, your pup can still have a fulfilling life. That's why it's so important to see your veterinarian regularly. Preventive care and lifestyle adjustments can go a long way in reducing your dog's risk and helping their heart be healthier.

Pet insurance can be a great way to help you get a dog with heart disease the treatment they need. At Pets Best, our dog insurance plans can be customized for your pet's unique needs. In addition, Pets Best policyholders can speak to a veterinary expert anytime through a 24/7 Pet Helpline.

Sources/ Citations

1. "Heart disease in dogs," Tammy Hunter (2023), VCA Animal Hospitals, https://vcahospitals.com/know-your-pet/heart-disease-in-dogs

2. "Heart disease — dogs," (n.d.), Cummings School of Veterinary Medicine at Tufts University https://vet.tufts.edu/foster-hospital-small-animals/specialty-services/cardiology/heartsmart/heart-disease-dogs

3. "Dilated cardiomyopathy in dogs: Closer to solving the mystery?" Caroline Coile (4/16/2024), American Kennel Club, https://www.akc.org/expert-advice/nutrition/dilated-cardiomyopathy-dogs-update/

4. "Cardiac arrhythmias in dogs — Types, symptoms, diagnosis & treatment," (8/30/2024), Carolina Veterinary Specialists Matthews, https://www.matthews.carolinavet.com/site/pet-health-blog/2024/08/30/cardiac-arrhythmias-dog

5. "Congestive heart failure in dogs: Symptoms, causes, and management," Veronica Higgs (1/27/2025), PetMD, https://www.petmd.com/dog/conditions/cardiovascular/c_multi_congestive_heart_failure_rt

6. "Can dogs have heart attacks? Causes, treatment, and prevention," Caroline Coile (9/25/2024), American Kennel Club, https://www.akc.org/expert-advice/health/can-dogs-have-heart-attacks/

7. "Early signs of heart disease in dogs," Andrea Johnson (3/15/2024), Wedgewood, https://www.wedgewood.com/blog/early-signs-of-heart-disease-in-dogs/

8. "Congestive heart failure in dogs: Prognosis & treatment," (12/15/2023), Atlantic Coast New York Veterinary Specialists, https://www.atlanticcoastvet.com/site/blog-long-island-vet/2023/12/15/congestive-heart-failure-dogs

9. "Congestive heart failure in dogs," (n.d.), Small Door Veterinary, https://www.smalldoorvet.com/learning-center/medical/congestive-heart-failure-in-dogs

10. "Diagnosis of cardiovascular disease in dogs," Suzanne M. Cunningham and Kursten V. Roderick (9/2024), Merck Veterinary Manual, https://www.merckvetmanual.com/dog-owners/heart-and-blood-vessel-disorders-of-dogs/diagnosis-of-cardiovascular-disease-in-dogs

11. "Caring for a dog with heart problems," (2/1/2021), PDSA, https://www.pdsa.org.uk/what-we-do/blog/caring-for-a-dog-with-heart-problems