Closeup of black and white dog with heart shaped cut out on nose

Key takeaway

Dog heart disease comes in many forms, with some dogs inheriting it from their parents and others developing it later in life. Knowing the signs of heart disease can help determine when it's time to get your dog diagnosed and treated. Left untreated, heart disease in dogs can be fatal.

Dogs and humans aren't so different — dogs can suffer from various ailments that affect humans, including heart disease. Like in humans, the heart plays an essential role in your dog's health and vitality. It's responsible for pumping blood throughout the body, and when it can't properly do its job, the health and life of the dog are at risk. 

Unfortunately, there are many forms of heart disease in dogs that can affect their health, as the term describes any number of illnesses that can affect the heart. If your dog has signs of heart disease, you must have them examined by a vet as soon as possible to prevent or treat serious, potentially fatal heart diseases like canine congestive heart failure. Heart disease can affect any dog, regardless of age, weight, or breed, so fast treatment is necessary to ensure your dog's quality of life and health. 

What Is Canine Heart Disease?

Heart disease is either congenital or can develop later in life. Puppies, adult dogs, and senior dogs are all at risk of heart disease, and there's no single cause. Heart conditions are more common as dogs age, but everything from aging and weight to nutrition can affect whether a dog develops heart disease. In addition, some breeds are more prone to some types of heart disease. For example, the Doberman is prone to dilated cardiomyopathy.1 

Types Of Heart Conditions In Dogs

Many types of heart disease affect dogs, but we'll only discuss the most common ones here. Since there are several heart conditions, you should talk to your vet about any your dog might be most prone to, depending on their health, age, and weight. Common types of heart disease in dogs include:

Valvular Degeneration

Valvular degeneration, also known as mitral regurgitation, is a valve disease and a common cause of heart murmurs in dogs.2 As dogs age, the heart muscles can thicken and weaken, preventing blood flow throughout the heart chambers and resulting in a backflow that leads to an enlarged heart when left untreated. When there are issues with the mitral valve, the heart must work harder to pump blood, which can cause several issues. Mitral valve disease (MVD) worsens over time and can lead to heart failure.2

There are four stages of this disease, and dogs may not show symptoms until the last stage, in which they may show signs of  congestive heart failure like breathing problems or collapse. Unfortunately, there is no cure for valvular degeneration, but it can be managed with monitoring, medication, and lifestyle changes.2

Dilated Cardiomyopathy (DCM)

Dilated cardiomyopathy in dogs is another common form of heart disease and occurs when the heart muscle becomes weak and less blood can be pumped out, causing an enlargement of the heart chambers. Dogs with DCM have hearts that can't properly pump blood and may have an irregular heartbeat.3 While DCM can affect any dog, it's most common in large or giant breeds.3

Dilated cardiomyopathy in dogs is typically a genetic disease passed from parent to puppy, but dogs can develop it due to poor diets, viruses, toxins, or certain medications.3 An increased risk of DCM has also been associated with grain-free dog diets. 

Like other forms of heart disease in dogs, there is no cure for DCM, but the condition can be managed with medication and other forms of treatment, depending on the stage. 

Types of heart conditions in dogs

Heart Arrhythmias

Heart arrhythmias are abnormal heartbeat rhythms and occur when the electrical impulses that tell the heart to beat fail and follow the wrong flow path. There are three common types of arrhythmias:

  • Tachycardia: Tachycardia is an increased heart rate in which your dog's heart will beat more times per minute. This type of arrhythmia can cause weakness and lethargy and, left untreated, can cause difficulty breathing. 
  • Bradycardia: Bradycardia is a decrease in the heart rate and can cause a dog's heart rate to fall as low as 20 beats per minute when asleep. Causes of bradycardia in dogs include diseases, head trauma, and underlying illnesses like hypothyroidism.4
  • Heart Block: Heart block can affect any breed and occurs when the heart can't pump blood properly through the ventricles, filling them with blood before they contract. In dogs with heart block, the ventricles are never told to contract.5 Animals not treated for heart block can collapse and develop heart failure, and most pets will need to be treated with a pacemaker.5

Any dog can get arrhythmia, but some specific types are commonly found in specific breeds. For example, ventricular arrhythmias are commonly found in boxers, bulldogs, and German shepherds.5 Arrhythmias can be detected during your dog's annual wellness visit when your vet listens to their heart. However, if you notice symptoms at home, you should have your dog examined as soon as possible. 

Congenital Heart Disease

When the word "congenital" describes something, it means the disease was present at birth. Congenital heart disease is typically genetic, but it could be caused by environmental factors, infections, medications, poor maternal nutrition, and poisoning.6 Many types of heart disease, including DCM and degenerative valve disease, may be caused by genetics.6 Congenital heart disease and defects must be detected as soon as possible, and while some may be corrected with surgery, when left untreated, any type of congenital heart disease could lead to congestive heart failure in dogs. 

Common congenital heart diseases in dogs include: 

  • Patent ductus arteriosus (PDA): PDA occurs when the ductus does not properly close when the puppy takes its first breath, causing blood flow to be forced from the left to the right chambers. This results in over-circulation and an enlargement of the left heart chambers, potentially causing arrhythmias. As the dog ages, they may develop congestive heart failure on the left side.6
  • Pulmonic stenosis: Pulmonic stenosis is a blockage in the blood flow from the right ventricle to the lungs. This causes the right ventricle to generate more pressure, leading to the enlargement and thickening of muscle fibers. Dogs with this condition may also develop other birth defects in the heart.6
  • Subaortic stenosis: Subaortic stenosis occurs when the fibrous tissue of the left ventricle experiences a reduction in flow due to obstruction. Subaortic stenosis is most common in large or giant breeds like German shepherds, Boxers, and Golden Retrievers.6
  • Ventricular septal defect (VSD): VSD defects are openings that occur in the wall between the right and left ventricles and can vary in size, affecting blood circulation. They may also occur alongside other types of abnormalities of the heart.6 

Signs of heart disease in dogs

Signs Of Heart Disease In Dogs

Unfortunately, some pets may not exhibit signs or symptoms of heart disease in dogs until the disease has progressed. However, some heart disease signs in dogs include: 

  • Coughing: A persistent cough could indicate heart disease if it doesn’t clear up in a few days. Dogs with heart disease cough due to fluid accumulation or leaking in the lungs. Enlarged hearts can also press on airways, causing coughing.7
  • Difficulty breathing: Heart disease in dogs can cause difficulty breathing, especially when lying down.7
  • Fainting: A reduction in heart function can lead to weakness because it deprives the brain and other vital organs of the oxygen and nutrients they need, leading to fainting and collapse in dogs.7
  • Lethargy: Dogs may tire more easily during walks or become less interested in their regular daily activities. 
  • Behavioral Changes: Dogs with heart disease may have a poor appetite or become more solitary. 
  • Bloated Abdomen: Some dogs may experience bloat during the later stages of heart failure in dogs due to the build-up of fluid. 

Diagnosing And Treating Dogs With Heart Disease

The diagnosis and treatment of heart disease in dogs depend on your dog's type and stage of the disease. 

Diagnosis

Treatment plans for heart disease in dogs depend on the type of heart disease, so it must be diagnosed by a veterinarian. Diagnostic tests may include:

  • Physical exam
  • Electrocardiogram (ECG) 
  • Echocardiogram
  • Chest X-ray
  • Blood Tests
  • Ultrasound

Treatment

Treatment plans for dogs with heart disease vary depending on the diagnosis. However, common treatments include: 

  • Medication
  • Surgery
  • Dietary Changes
  • Weight loss

Treatment aims to minimize the damage to the heart and control fluid accumulation to improve lung function and circulation while regulating the heart rate.8

FAQs

What dog breeds are at higher risk for heart disease?

Large and giant dog breeds are at a higher risk for heart disease. These breeds include:

  • Dobermans
  • Great Danes
  • Irish wolfhounds
  • Boxers
  • Saint Bernards

However, there are many causes of heart disease, and any dog can get heart disease, whether or not they're born with it or predisposed. Therefore, it's important to take your dog to the vet as soon as you notice any symptoms or signs of heart disease or heart failure. 

Can dogs be cured of heart disease?

There is no cure for heart disease in dogs, but the disease can be managed and treated with surgery, lifestyle changes, or medications. With the right treatment early on, dogs can continue to live happy and healthy lives with little to no symptoms. 

Can you prevent a dog from contracting heart disease? 

In many cases, there's no way to prevent heart disease in dogs, especially since genetics play a factor. However, you should continue to support your dog's overall health by:

Female Hispanic dog owner cuddling French bulldog puppy

Final Notes

There are many forms of heart disease in dogs, and unfortunately, there's no cure for any of them. However, that doesn't mean your dog can't go on to live a healthy, happy life with a heart disease diagnosis. If you notice the signs of heart disease, you should have your pet examined by a vet as soon as possible. 

While there is no cure, the disease can be managed, so it's important to follow your vet's instructions for medications and at-home care. Worried about your dog's heart? Talk to a Dutch vet to discuss diagnosis and treatment options for dogs with heart disease. Try Dutch telemedicine for pets today.

References

  1. “Heart Problems in Dogs.” PDSA, https://www.pdsa.org.uk/pet-help-and-advice/pet-health-hub/conditions/heart-problems-in-dogs.

  2. “Mitral Valve Disease in Dogs.” PDSA, https://www.pdsa.org.uk/pet-help-and-advice/pet-health-hub/conditions/mitral-valve-disease-in-dogs.

  3. “DCM (Dilated Cardiomyopathy) in Dogs.” PDSA, https://www.pdsa.org.uk/pet-help-and-advice/pet-health-hub/conditions/dcm-dilated-cardiomyopathy-in-dogs.

  4. Rebecca E. Gompf, DVM, MS, DACVIM (Cardiology). https://www.saintfrancis.org/wp-content/uploads/Sinus-Bradycardia.pdf.

  5. “Arrhythmias (Abnormal Rhythms) in Dogs.” Cornell University College of Veterinary Medicine, 29 Jan. 2018, https://www.vet.cornell.edu/hospitals/companion-animal-hospital/cardiology/arrhythmias-abnormal-rhythms-dogs.

  6. Tou, Sandra P. “Congenital and Inherited Disorders of the Cardiovascular System in Dogs - Dog Owners.” Merck Veterinary Manual, 29 Sept. 2022, https://www.merckvetmanual.com/dog-owners/heart-and-blood-vessel-disorders-of-dogs/congenital-and-inherited-disorders-of-the-cardiovascular-system-in-dogs.

  7. “5 Common Signs of Heart Disease in Dogs.” Morris Animal Foundation, https://www.morrisanimalfoundation.org/article/heart-disease-signs-dogs.

  8. Cunningham, Suzanne M., and Kursten V. Roderick. “Treatment of Cardiovascular Disease in Dogs - Dog Owners.” Merck Veterinary Manual, 29 Sept. 2022, https://www.merckvetmanual.com/dog-owners/heart-and-blood-vessel-disorders-of-dogs/treatment-of-cardiovascular-disease-in-dogs.