How long does congestive heart failure last in dogs?

Congestive heart failure (CHF) is a term that refers to the heart's inability to pump adequate blood to the body. There are many causes of CHF in dogs. The two most common causes are:

• mitral valve insufficiency (MVI). MVI is a leaky mitral valve, which is the valve between the left atrium and the left ventricle.
• dilated cardiomyopathy (DCM).

For further information on these specific causes, please see the handouts "Dilated Cardiomyopathy in Dogs" and "Mitral Valve Disease in Dogs".

Clinical signs of CHF vary depending on whether the dog has left- or right-sided heart failure.

What is the difference between right-sided and left-sided CHF?

Right-sided congestive heart failure (RS-CHF) causes poor venous blood return to the heart. In other words, when the heart contracts or pumps, instead of the right ventricle pushing the blood through the lungs for oxygenation, some blood leaks through the tricuspid valve (the valve between the right atrium and right ventricle) back into the right atrium. This blood backs up into the systemic circulation (the main circulation of the body) and consequently becomes congested. Fluid accumulates in the abdomen, interfering with the function of the organs in these areas. The abdomen may fill with fluid, a condition called ascites. Fluid may also leak from veins in the limbs, causing swelling, known as peripheral edema.

In left-sided congestive heart failure (LS-CHF), when the heart contracts or pumps, instead of the left ventricle pushing the blood into the systemic circulation, some blood leaks through the mitral valve back into the left atrium and then it backs up into the lungs. Fluid then seeps into the lung tissue resulting in pulmonary edema. This causes coughing and difficulty breathing. Left-sided congestive heart failure (LS-CHF) is the most common form of congestive heart failure. The classic signs of heart failure, coughing and fluid in the chest, are most commonly caused by LS-CHF.

Is CHF due mainly to heart valve disease?

CHF is most commonly caused by valvular insufficiency. It is estimated that 80% of the canine CHF cases are caused by MVI. However, there are many other causes. Disease of the heart muscle (cardiomyopathy), irregularities of rhythm, and narrowing of some of the major blood vessels can also cause CHF. Initially, MVI results in left-sided congestive heart failure. If left untreated, the heart failure may progress to involve both sides of the heart.

What clinical signs should I expect?

The most common clinical sign of congestive heart failure (CHF) is persistent coughing accompanied by difficulty breathing. This is due mainly to pulmonary edema or the accumulation of fluid in the lungs. The enlarged heart will also push against the trachea, causing irritation that can induce a cough.

"The most common clinical sign of congestive heart failure is persistent coughing accompanied by difficulty breathing."

Many dogs with CHF will tire out more easily, have reduced stamina, and do not engage in playing or walking as they once did. Coughing when at rest or sleeping, excessive panting, persistent loss of appetite, a swollen belly, and pale or bluish gums are also signs associated with heart failure. The dog will develop generalized weight loss and muscle wasting due to the effects of CHF on other body systems. If any of these signs develop in a pet with a heart murmur, notify your veterinarian immediately.

Do dogs have heart attacks?

In humans a heart attack usually refers to myocardial infarction (MI). Myocardial infarction refers to death of the cells in an area of the heart muscle or myocardium. Cell death is usually due to oxygen deprivation caused by obstruction of the coronary blood vessels that supply blood to the heart muscles. Heart attacks are rare in dogs but unexpected and sudden death in dogs diagnosed with any form of heart disease is possible.

How is CHF diagnosed?

As with any heart problem, diagnosis involves several tests:

Auscultation or listening to the heart with a stethoscope is the first step in diagnosing heart disease. Heart murmurs are detected by auscultation; the murmur's location and intensity help determine its significance. The heart rhythm is assessed, and if there are concerns, the veterinarian may simultaneously palpate or feel the pulse to determine its strength and rhythm. Finally, the lungs are assessed, looking for evidence of changes associated with heart failure.

Chest X-rays are taken to evaluate the size and shape of the heart and look for lung changes such as the presence of fluid.

Blood and urine tests are performed to give an indication of any other disorders in the body. Liver and kidney function are often impaired in patients with heart disease.

An electrocardiogram (ECG) measures the electrical activity of the heart and allows accurate determination of both heart rate and rhythm. Any abnormal rhythms (arrhythmias or dysrhythmias) can be detected and evaluated.

Ultrasound examination (echocardiogram) utilizes ultrasound waves to evaluate the heart. The size and thickness of each heart chamber can be evaluated, and the effectiveness of the heart's contractions can be directly observed. Measurements can be taken to evaluate the heart's pumping efficiency.

Can't you treat my dog without these tests?

Accurate diagnosis gives your veterinarian a much better guide to the type and extent of treatment necessary. Today there is a wide selection of heart medications that can be used to treat congestive heart failure and the treatment regime must be tailored for each patient. Without these tests, your veterinarian is unable to determine the optimal treatment for your pet, and may inadvertently cause more harm than good. With proper treatment, many dogs are able to live a normal life for many months to years.

Q: What is congestive heart failure?

A: Similar to humans, dogs can develop many conditions affecting the heart that may eventually lead to heart failure. These could include abnormalities of the heart valves, heart muscle, or blood vessels entering or exiting the heart. As the condition progresses, fluid can build up in the lungs, chest, and abdomen. This syndrome is called congestive heart failure.

Q: What are the signs of congestive heart failure?

A: Heart disease in dogs is commonly first suspected after the dog develops a cough or decreased energy on walks (which is known as exercise intolerance). You may notice that while your dog used to be able to walk the same route every day with good energy, they are now lagging behind partway through your normal route. You may also notice a soft cough, particularly after your pet has been lying down. 

Q: How is congestive heart failure diagnosed?

A: Your veterinarian will listen to your dog’s heart to assess the heart rate, heart rhythm, and whether they can hear a heart murmur. A heart murmur occurs when the valves of the heart do not close completely each time the heart beats, which results in the ‘whooshing’ sound through the stethoscope. They will also listen to your pet’s lungs and assess their respiratory rate. Your veterinarian will likely then recommend an x-ray to assess the size and shape of your dog’s heart, and to evaluate whether there is any fluid present in the chest. Depending on what is seen in the x-rays, your veterinarian may also recommend that your dog have a cardiac ultrasound done, which is called an echocardiogram.

Q: Does congestive heart failure shorten a dog’s life?

A: Average life expectancy varies based on the cause of your dog’s heart disease, and how advanced it is. In most cases, it is possible that heart disease will shorten your dog’s lifespan. This is why it is important to obtain a correct diagnosis early of heart disease to be able to begin the appropriate medication. The most important thing you can do to support your dog is to take your dog for regular physical exams. This is usually done once a year for adult dogs, and twice a year for senior dogs over 7. 

Q: What breeds are most at risk for congestive heart failure?

A: For some of the more common types of heart disease, certain breeds are known to be more at risk. 

In the case of Degenerative Valvular disease, small breed, older dogs are more at risk. For example: Chihuahuas or King Charles Cavalier Spaniels.

In the case of Dilated Cardiomyopathy, large breed, older dogs are more at risk. For example: Great Danes, Irish Wolfhounds or Doberman Pinschers.

Q: What can be done to slow the progress of congestive heart failure?

A: Depending on what is discovered during your veterinarian’s exam, they will likely prescribe heart medication for your dog. The most common heart medications used in pets support the heart in a few different ways: by dilating blood vessels which make it easier for the heart to pump blood through the body; by sensitizing the heart muscle to calcium which improves the contractility of the heart; or by lowering blood pressure. Studies have shown that dogs who were started on a medication before showing clinical signs of heart disease had a better long term prognosis. Based on this knowledge, it is important to more thoroughly assess your pet’s heart soon after your veterinarian can hear changes through the stethoscope, or as soon as your pet is showing signs suggestive of heart disease. 

Q: Is a dog with congestive heart failure in pain?

A: No. Heart disease should not be painful for your pet.

Q: Can a dog with congestive heart failure still lead a relatively normal life?

A: Most dogs with mild heart disease can lead a normal life. Owners will need to be more aware of their activity level and not allow the dog to over-exert themselves. As the disease progresses, it is likely you will notice a decrease in their energy and that they tire more easily.

Q: At some point will my vet recommend putting a dog with congestive heart failure to sleep?

A: Unfortunately, there will come a time when your dog’s quality of life has deteriorated. You will need to make a decision together with your veterinary team regarding when the time is right to consider humane euthanasia.