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Congestive Heart Failure in Dogs: Causes, Symptoms, Treatment

Nicole Cosgrove

May 25, 2021

Congestive heart failure occurs in dogs when their heart is no longer able to pump blood effectively to the rest of the body.1 There are two main causes for this disease, including mitral valve insufficiency and dilated cardiomyopathy.

Congestive heart failure is a serious condition that often isn’t curable unless the underlying cause is fixed. Medication is often required to help reduce the side effects of this disease.

Clinical symptoms depend largely on the type of heart failure that your dog has.

Types of Congestive Heart Failure in Dogs

dog anesthesia with veterinary treatment
Image credit: thirawatana phaisalratana, Shutterstock

There are two main types of congestive heart failure: right-sided and left-sided. These have different symptoms.

Right-sided heart failure causes oxygen-poor blood to return into the heart. Basically, when the heart pumps, some of the poorly oxygenated blood leaks backward instead of going to get oxygenated. This causes the circulation in the body to become backed up and congested. Fluid begins to accumulate in the abdomen, which may fill up with fluid. This excess fluid may be carried to the extremities, causing swelling.

Left-sided heart failure occurs when oxygenated blood leaks backward toward the lungs. It’s already oxygenated, so it doesn’t need to return to the lungs. This causes excess fluid around the lungs, resulting in pulmonary edema. This causes difficulty breathing and coughing, as the body thinks that there are foreign objects inside the lungs. This is the most common cause of heart failure.

Heart failure can progress to affect both sides of the heart if left untreated.

What’s the Main Cause of Congestive Heart Failure?

Most accounts of congestive heart failure are caused by mitral valve insufficiency. Up to 80% of congestive heart failure cases occur for this reason. This causes left-sided heart failure, which is one of the reasons that it is much more common than the right-sided variation.

However, there are other causes as well. For instance, cardiomyopathy is a disease of the heart muscle that makes it unable to pump efficiently, causing congestive heart failure. Irregularities of beating and narrowing of major blood vessels can also cause congestive heart failure.

What Are the Symptoms of Congestive Heart Failure?

 dogs-Lenkadan, Shutterstock
Image Credit: Lenkadan, Shutterstock

The most common signs of congestive heart failure are difficulty breathing and a persistent cough. These may seem like minor symptoms, but they point to something more serious. These only occur with left-sided heart failure, as they are caused by a build-up of fluid around the lungs.

Occasionally, an enlarged heart may also push against the trachea, causing irritation and coughing. This can occur with right-sided and left-sided heart failure. Therefore, coughing isn’t necessarily always a sign of right-sided heart failure.

Dogs with heart failure often fatigue faster, as they are unable to deliver oxygen to their body efficiently. Excess panting, loss of appetite, a swollen belly, and pale gums are also symptoms of heart failure. Some dogs may even begin to lose muscle mass.

Is Heart Failure the Same as a Heart Attack?

No, heart failure can lead to a heart attack. However, heart attacks are rather uncommon with dogs. Heart attacks are caused by death to the cells around the heart. Usually, this cell death is caused by oxygen deprivation by the obstruction of the blood vessels around the heart. Sudden deaths in dogs are sometimes attributed to heart attacks.

How Is Congestive Heart Failure Diagnosed?

Dog check up_Sergey Mikheev_Shutterstock
Image Credit: Sergey Mikheev, Shutterstock

There are many tests that can help vets diagnose heart failure and determine the type and cause of heart failure.

Typically, vets will listen to the heart with a stethoscope. If the dog has heart failure, they may be able to detect heart murmurs and determine their location. This is the first step to determining that the dog has heart failure. The lungs will likely be checked at the same time to check for signs of heart failure.

Chest X-rays are used to determine the size of the heart and the presence of any fluid. This can go a long way toward determining if the dog has heart failure, as both are tall-tale signs. Blood and urine tests will also likely be performed. These can’t determine heart failure directly, but they can rule out other problems and check the liver and kidney function, which may be compromised in dogs with heart failure. Blood tests are important to determine the overall health of the dog and can help when determining the best treatment options.

An electrocardiogram can be used to measure the electrical activity of the heart, allowing the vet to determine its exact rate and rhythm. However, this is often not necessary, as the vet can determine many of these things using a stethoscope. An ultrasound of the heart may also be made, as this allows the vet to see the heart clearly. The size and thickness of each heart chamber can be determined, and the efficiency of the heart can be directly determined.

How Is Congestive Heart Failure Treated?

dog medicine_Shutterstock_LightField Studios
Image Credit: LightField Studios, Shutterstock

Treatment depends on the cause of the dog’s congestive heart failure and how progressed it is. Based on your dog’s symptoms and the things observed in the tests, different courses of treatment may be recommended.

Medication may be used to help the heart work more efficiently and control irregular heartbeats, which can be inefficient. It may also be used to lower the fluid levels around the lungs if that is necessary. Surgery may be required to correct a torn valve. Pacemakers are rarely used, but they may be suggested by some vets.

A special diet may be necessary to prevent extra fluid build-up. Low-sodium diets may help with fluid build-up and limit the progression of the disease. Limited activity may be recommended to avoid putting excess strain on your dog’s heart.

Sometimes, supplements are suggested. These will vary depending on your dog’s diet, specific symptoms, and blood results. Vitamin B, taurine, carnitine, and antioxidants may be helpful.

Your vet may also want to check for heartworms and bacterial infections of the heart. If any are found, then specific medications to treat those problems will likely be recommended.

Multiple vet visits will likely be necessary. A treatment plan will need to be created and your dog monitored. Changes may need to be made in medications.

Want to learn more about other dog diseases and ailments?


Featured Image Credit: ESB Professional, Shutterstock

Nicole Cosgrove

Nicole is the proud mom of Baby, a Burmese cat and Rosa, a New Zealand Huntaway. A Canadian expat, Nicole now lives on a lush forest property with her Kiwi husband in New Zealand. She has a strong love for all animals of all shapes and sizes (and particularly loves a good interspecies friendship) and wants to share her animal knowledge and other experts' knowledge with pet lovers across the globe.

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