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Home > Dogs > Congestive Heart Failure in Dogs: Vet-Reviewed Causes, Signs & Treatment

Congestive Heart Failure in Dogs: Vet-Reviewed Causes, Signs & Treatment

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Reviewed & Fact-Checked By

Dr. Marta Vidal-Abarca

Veterinarian, BVSc GPCert (Ophthal) MRCVS

The information is current and up-to-date in accordance with the latest veterinarian research.

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

Congestive heart failure is a serious condition that requires a joint effort between you and your veterinarian. Medication and frequent check ups are necessary to maintain your dog’s quality of life as well as possible.

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

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Types of Congestive Heart Failure in Dogs

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Being as the heart is an organ with four chambers, there are two main types of congestive heart failure: right-sided and left-sided. These manifest in different ways. 

Right-sided heart failure causes an abnormal circulation of oxygen-poor blood. Basically, when the heart pumps, some of the poorly oxygenated blood leaks backward to the body instead of going to the lungs 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 causes abnormal flow of oxygenated blood, which leaks backward from the left ventricle into the left atrium. This causes pressure overload to the left side of the heart and fluid accumulation within the lungs, resulting in pulmonary edema. This causes difficulty breathing and coughing, and it 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 (MVI). This valve is located between the left atrium and the left ventricle, and it causes left-sided heart failure, which is one of the reasons that it is much more common than the right-sided variation. Up to 80% of congestive heart failure cases occur due to mitral valve disease. 

However, there are other causes as well. For instance, dilated cardiomyopathy (DCM) 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.

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What Are the Signs of Congestive Heart Failure?

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The most common signs of congestive heart failure are difficulty breathing and a persistent cough. These may initially seem like minor signs, but they point to something more serious. Signs will progress and become more frequent and severe, affecting your dog’s quality of life and decreasing their lifespan unless treatment is started promptly.

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 left-sided heart failure.

Dogs with heart failure often fatigue faster, as they are unable to deliver oxygen to their body efficiently. They may also faint (lose consciousness temporarily) if oxygen is not delivered to their brain effectively. Excess panting, loss of appetite, a swollen belly, and pale gums are also common signs 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. A heart attack occurs when the heart muscles don’t receive blood flow because of a circulation problem or if the arteries get blocked. This is different from cardiac arrest, which is caused by an electrical problem and when the heart does not work properly and stops beating. Sudden deaths in dogs are sometimes attributed to heart attacks.

How Is Congestive Heart Failure Diagnosed?

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

Typically, vets will start by examining your dog and listen to the heart and lungs with a stethoscope. Sometimes, they may be able to detect heart murmurs and determine their location and severity. This is the first step to determining that the dog has a heart disease. The lungs will also be checked at the same time to check for signs of pulmonary oedema.

Chest X-rays are used to determine the shape and 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. An ultrasound of the heart is usually necessary, as this allows the vet to see the heart muscle and valves working and how the blood flows. 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?

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Treatment depends on the cause of the dog’s congestive heart failure and how advanced it is. Based on your dog’s signs 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 body if that is necessary. Surgery may be required, especially with congenital heart problems when the dogs are born with a defect. Pacemakers are rarely used, but they may be suggested by some vets.

A special diet may be recommended by your vet. Generally speaking, low-sodium and high-quality protein diets will be beneficial. Exercise should be tailored to your dog’s needs. Sometimes, supplements are suggested. These will vary depending on your dog’s diet, specific signs, and blood results. Omega-3 fatty acids, potassium, magnesium, and amino acids 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 and joint efforts will be necessary. A treatment plan will need to be created and your dog monitored. Changes may need to be made in medications.

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Final Thoughts

Congestive heart failure is a severe complication from heart disease. We hope this article has answered some questions you might have if your dog has been diagnosed with a heart problem. The information presented here may also help you understand the steps your vet needs to take in order to properly diagnose this disease and how to maintain and improve your dog’s quality of life as much as possible.

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