As dogs age, the heart muscle can weaken, reducing the ability to pump blood efficiently throughout the body. This strain often causes fluid buildup in the body; a condition known as Congestive Heart Failure (CHF).

Although heart failure may not happen to every pet, it becomes more and more likely the older your pet becomes. The sooner you recognize the warnings signs of heart failure and take action, the better your dog’s quality of life can be. 

What is Heart Failure in Dogs? 

There are two important terms you may hear when it comes to your dog’s heart health:

• Heart disease in dogs

  This is a broad term that covers a variety of conditions affecting the heart, such as a murmur or an arrhythmia. At this stage, your dog may not show any symptoms and may continue to live a full, active life.

  
  

• Heart failure in dogs

  This refers to the point when heart disease has progressed and the heart can no longer function at full capacity. As the heart’s performance decreases, it can no longer pump blood efficiently to the body’s muscles and organs, leading to noticeable symptoms. Heart failure may progress into Congestive Heart Failure (CHF), where fluid builds up in the lungs or other organs. This fluid accumulation can severely affect your dog’s ability to breathe and function normally.

Learn the signs of congestive heart failure in dogs. If signs of CHF develop, our VEG emergency vet staff is available around the clock to help manage your dog's symptoms.

Types of Heart Failure

Like humans, a dog’s heart has four chambers, divided into two sides that work together to circulate oxygen throughout the body.The right side receives blood that needs oxygen, while the left side pumps oxygen-rich blood back out to the body. Heart failure is generally: Left-Sided CHF or  Right-Sided CHF.

Left-Sided Congestive Heart Failure (most common) 

This occurs when the left side of the heart can’t pump oxygenated blood efficiently into the body. As a result, fluid backs up into the lungs. Dogs with left-sided CHF often develop respiratory symptoms such as persistent coughing (often dry), difficulty breathing, or rapid breathing.

Right-Sided Congestive Heart Failure

When the right side of the heart struggles to pump blood returning from the body, this causes fluid to build up in areas like the abdomen, chest cavity, or limbs. Dogs with right-sided CHF may show swelling in the belly (ascites), fluid retention, or generalized swelling in the legs.

Causes and Risk Factors of CHF in Dogs

Some conditions and risk factors can increase your dog’s chances of developing heart failure. If your pet has any of these, it’s especially important to stay observant and contact your veterinarian promptly if you notice any signs of heart disease. While the diagnosis may feel overwhelming, it is not automatically a crisis. With proper care, treatment, and monitoring, many dogs continue to live full, happy lives for years.

Common causes of CHF in dogs 

Mitral Valve Disease (MMVD)

This is the most common cause of heart disease in dogs. The mitral valve acts as a doorway between the left atrium and left ventricle. In dogs with MMVD, this valve does not close completely, allowing blood to leak backward into the left side of the heart. Over time, this improper blood flow puts added strain on the heart and can eventually lead to left-sided congestive heart failure. MMVD is most often seen in smaller breed dogs, and research shows there is a genetic link in its development.

Dilated Cardiomyopathy (DCM)

This inherited disease is most common in large-breed dogs. DCM develops when the heart muscle becomes weak and stretched, causing the heart to enlarge. As the muscle loses strength, the heart cannot contract effectively, which reduces its ability to pump blood efficiently throughout the body. Over time, this weakening can progress to congestive heart failure.

Heartworm

Mosquitoes can transmit this invisible but dangerous parasite to dogs. Once inside the body, heartworms migrate into the blood vessels of the heart and lungs, where they can grow up to 5–12 inches long. Even after treatment clears the parasites, they often leave behind lasting damage to the heart and lungs. Fortunately, heartworm disease is preventable with monthly medication. Talk with your veterinarian about the right prevention plan and dosage for your dog.

Congenital Defects

Some puppies are born with heart abnormalities that are present from birth. In some cases, these may resolve as the puppy matures. However, other defects may persist or progress over time. Early veterinary evaluation is important to determine whether the condition is harmless or requires monitoring and treatment. Detecting congenital heart disease early can give your pet the best chance at a long and healthy life.

Risk factors of CHF in dogs

Breed  

Miniature Poodles, Cocker Spaniels, Terrier breeds, and some larger dogs such as Great Danes, Boxer, and  Dobermans are genetically predisposed to heart failure. 

Age

As dogs grow older, their risk of developing heart disease, and eventually heart failure, increases naturally. By the time a dog reaches around seven years of age, the likelihood of heart disease rises significantly (by as much as 60%). Regular veterinary checkups become especially important in senior dogs to catch early signs of heart issues and begin treatment or monitoring as soon as possible.

Obesity:

Maintaining a healthy weight is an important part of reducing your dog’s risk of heart failure. Extra weight forces the heart to pump harder to deliver blood throughout a larger body. Over time, this added strain can cause the heart muscle to weaken or thicken, increasing the likelihood of developing heart disease. Keeping your pet at a healthy weight through balanced nutrition and regular exercise is one of the most effective ways to support long-term heart health.

Our compassionate and competent veterinary staff will have open, honest discussions with dog owners, and describe the best ways to provide quality of life for dogs with CHF.

Common Symptoms of Heart Failure in Dogs

Now that you understand the types of heart disease and how it can occur, read on for a list of common symptoms to watch out for.  

With the help of this guide, you can choose when it’s time to call the vet. If you ever have any questions or concerns regarding your pet’s health, you should always contact a veterinarian or emergency vet as soon as possible so you can quickly find the underlying cause of your pet’s behavior.

Dr. Jason Dombrosky, a Medical Director at VEG ER for Pets, provides the following symptoms for heart failure in dogs:

6 common symptoms of heart failure in dogs

1. Frequent Coughing is a Sign of Heart Failure in Dogs

Frequent coughing is often the first sign many pet owners notice in their dogs with heart failure. The type of coughing associated with heart failure is usually dry, although some pets may cough up foam with or without blood in it.

The cough will worsen with time as the heart disease progresses. Eventually, pets will cough even when they are at rest, and eating may become more difficult for them because of this symptom too.

2. Pacing and Restlessness is a Sign Dog May Have Heart Failure

Dogs are prone to pacing and restlessness from heart failure. Pets may pace because they are in pain from their heart failure or because the secondary symptoms associated with heart failure are causing discomfort.

Additionally, pets may become restless when they have heart failure because they know something is wrong. They may not realize how serious their condition is, but they still recognize that they don’t feel well and are unsure what to do about it. This may lead to anxiety, so some pets are given anxiety medication in later stages of heart failure.

3. Wheezing or Panting

Early intervention by a veterinarian or emergency vet allows your pet the best quality of life since heart failure is a progressive condition that worsens over time. As heart failure progresses, pets will have more and more difficulty breathing. You may notice your pet’s sides heaving in and out more when she breathes, or you may hear her wheezing in her sleep or otherwise at rest. She may also pant or breathe with her mouth open more often.

Trouble breathing can be associated with a wide variety of health problems in pets. However, if your pet has already been diagnosed with heart failure and experiences this symptom, the two are likely linked.

4. Swollen Abdomen is a Symptom of Heart Failure in Dogs

In later stages of heart failure, some pets may experience a swollen stomach. This symptom is due to the buildup of fluid in the body from the weakening of the heart. Although pets may still live for some time with a swollen abdomen, it is a sign that they have entered the last stages of heart failure.

If your pet seems to be in a lot of pain or discomfort from her swollen abdomen, it may be time to talk to the vet about euthanasia. This is never an easy decision to make for any pet owner, and your vet will work with you to choose when the time may be right.

5. Lethargy and Weakness in Dogs Can Mean Heart Failure

Other common symptoms of heart failure in dogs are lethargy and weakness. Lethargy and weakness are both associated with a wide range of health problems in dogs. However, if your pet becomes weak or lethargic along with other specific symptoms on this list, then heart failure may be the underlying cause.

If your pet is diagnosed with heart failure and you notice her growing more and more lethargic and weak, this is normal. The disease is progressing, and your pet is weakening as a result of it. Do what you can to keep her comfortable and manage her symptoms throughout the rest of her life.

6. Fainting or Collapsing Can Be Due to Heart Failure in Dogs

Finally, fainting or collapsing may occur along with heart failure in some pets. If your pet suddenly faints or collapses and you know she has heart failure, you may not choose to take her to the vet, depending on the end of life plan you have for her.

If you are unsure what has caused your pet to suddenly collapse or faint, however, take her to the emergency vet immediately. It could be heart failure, but it could be any number of other issues instead.

Treatment Options for CHF in Dogs

Take your dog to a VEG emergency vet hospital for any heart failure symptoms

As you can see, there are many signs of heart failure associated with dogs. If you have a senior pet, or any pet with a known chronic health condition, it’s a good idea to watch for these symptoms. This way, you’ll know when something’s going wrong with your pet, and you’ll be ready to go to the vet.

While there is no cure for heart failure in dogs, some pets may live a long time in early to moderate stages of heart failure.

If you notice your dog exhibiting any of the symptoms of heart failure as mentioned above, you should seek veterinary care as soon as possible. 

VEG Emergency Vet Hospitals are Always Open

VEG has locations all over the country that are open 24 hours a day, on weekends and holidays too. All of our hospitals are staffed with compassionate, caring professionals who always put the wellbeing and comfort of your pet first. So don’t wait, make sure your pet gets the care she needs by calling and speaking to one of our emergency vets now.