Congestive Heart Failure in Dogs

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Congestive heart failure (CHF) is fairly common in dogs. Approximately 10% of all dogs, and 75% of senior dogs, have some form of heart disease. CHF itself is not a disease: it is a condition that is a result of heart disease. More specifically, CHF occurs when the heart is unable to pump an adequate amount of blood to the body, thus causing an increase in pressure and fluid that eventually leaks into the lungs and, less frequently, other major organs.

When fluid accumulates in or around a dog’s lungs, it prohibits the lungs from expanding normally and prevents oxygen from moving into the bloodstream properly. This can cause a variety of symptoms and health issues.

CHF can be a slow-onset condition that develops over time.

Signs and Symptoms of CHF in Dogs

The signs and symptoms associated with CHF may vary, depending on the underlying heart disease and whether the right or left side of the heart is affected. In some cases, symptoms will be the same regardless of side.

These signs should be taken seriously and addressed with your veterinarian at first notice:

  • Fainting
  • Difficulty breathing / shortness of breath
  • Inability to exercise
  • Persistent coughing
  • Fatigue
  • Pacing before bedtime and difficulty settling down
  • Lack of appetite
  • Swollen belly (due to fluid buildup)
  • Weight loss
  • Change in gum and/or tongue color to a bluish gray (a result of poor oxygen flow)
  • Increased heart rate
  • Crackling sound when listening to the lungs

Left-sided congestive heart failure: This is the most common type of CHF in dogs. The left side of the heart collects oxygen-rich blood and pumps it out to the body’s various organs. Certain signs such as coughing, difficulty breathing, and exercise intolerance are indicative of a backup of pressure in the vessels delivering blood to the left atrium (upper chamber) and ventricle (lower chamber). As a result, fluid accumulates within the lungs (a condition known as pulmonary edema). On occasion, dogs with left-sided CHF faint due to lack of blood flow and oxygen to the brain. They often breathe faster than healthy dogs.

Right-sided congestive heart failure: If the right side of the heart is weak or there is a dysfunctional valve, the heart is unable to pump enough blood to the lungs for oxygenation. Pressure builds up in the vessels that deliver blood to the right atrium, and the body’s veins and capillaries. This can cause fluid buildup in the abdomen, a condition called ascites. Fluid may also leak from veins in the limbs and cause swelling, a condition known as peripheral edema.

Biventricular failure: This arises when both the right and left ventricles are not working properly.

Both right-sided and left-sided CHF ultimately lead to oxygen depletion in the tissues, and eventual heart failure.

How Did My Dog Get Congestive Heart Failure?

There are a number of factors that can result in CHF. Some dogs are born with congenital heart defects that contribute to this condition, but they can take years to present themselves. Congenital heart disease is rare, accounting for about 5% of all canine heart disease.

Common congenital heart diseases include:

  • Mitral valve insufficiency (leaky valve disease). While mitral disease can be congenital, we typically see it develop more in middle or old age.
  • Dilated cardiomyopathy (an enlarged heart)
  • Atrial septal defect (hole in the heart)
  • Patent ductus arteriosus or PDA (failure of a particular blood vessel to close normally at the time of birth)

Dogs that are born with healthy hearts can develop heart disease during their lifetime. Like humans, dogs can develop health issues that can lead to CHF as they age. Other causes of CHF in dogs:

  • Heartworms: Heartworms can block heart valves, or even clog an entire heart chamber. See our article on heartworm preventative.
  • Hormones: The thyroid especially can affect the heart’s function and performance. For example, a dog with hypothyroidism usually has a slower-than-normal heart rate.
  • Parvovirus: This virus can potentially infect the heart muscles, and can even cause acute heart failure in dogs.
  • Bacterial infections: Bacteria from the mouth can get into the bloodstream and attach to the heart valves, causing inflammation in the lining of the heart or in the valves. (This is why good dental care is extremely important. Check out our article on how to brush your dog’s teeth.)
  • Nutritional deficiency: A lack of vitamin E or selenium can cause damage to the heart muscles.

Diagnosing Congestive Heart Failure in Dogs

The veterinarian will need your dog’s complete medical history along with a complete physical exam to diagnose CHF. An accurate diagnosis will require a series of tests:

  • Blood and urine tests: Dogs with heart disease often have problems with their liver and kidneys.
  • Chest x-rays: These reveal the size and shape of the heart, as well as any changes in the lungs (e.g., fluid buildup).
  • Electrocardiogram (EKG): This test detects abnormalities in the electrical activity of the heart (rate and rhythm).
  • Ultrasound (echocardiogram): This tests examines the size, shape, and movement of the heart. It can also determine whether the heart is pumping efficiently. This diagnostic test should be performed only by a board-certified veterinary cardiologist (or by a cardiology resident-in-training).
  • Heartworm antigen test: This test detects abnormal proteins produced by heartworms.

CHF in dogs is broken down into four stages. Stages one and two present few symptoms, and owners may be unaware something is wrong until the condition has progressed to a later stage.

  • Stage 1: The dog’s heart is beginning to deteriorate. Visible signs and symptoms have not yet presented themselves.
  • Stage 2: Symptoms like panting, shortness of breath, and fatigue, especially after exercising, begin to present themselves.
  • Stage 3: Fatigue and shortness of breath occur more frequently, even on short walks. Coughing and wheezing may begin. Since the heart is not pumping efficiently, an accumulation of fluid in the chest causes breathing difficulties.
  • Stage 4: CHF is in its final stage. Breathing becomes difficult even when at rest. Fluid can accumulate in various parts of the body, causing swollen legs or belly, making it difficult to walk. It can even cause vomiting.

Treating Your Dog for Congestive Heart Failure

Treatment depends on the underlying heart disease, along with the severity. There is usually no cure for CHF, but there are effective treatments to ensure a good quality of life. If the cause of CHF is a congenital abnormality like a PDA, surgical correction may help to reverse heart failure if performed in a timely fashion. The goal when treating CHF is to reduce fluid buildup and maximize the amount of blood being pumped to the lungs and the rest of the body.

Here are some of the medications, supplements, and diets that may be recommended:

  • ACE inhibitors (enalapril, benazepril, captopril): Help reduce blood volume and pressure, relieve stress on the heart, and slow the deterioration of the heart muscles.
  • Diuretics: Help stimulate the kidneys to remove excess fluid buildup in the lungs and abdomen.
  • Vasodilators and positive inotropic drugs: Vasodilators help relax blood vessels and decrease pressure on the heart, allowing it to pump blood more easily. Positive inotropes increase the force with which the heart muscle beats, allowing the heart to pump more blood to the lungs and the rest of the body.
  • Nutrition: Limiting the amount of sodium in your dog’s diet can decrease fluid buildup in the body. Supplements like vitamin B, taurine, and carnitine, along with antioxidants like coenzyme Q10 and vitamin E, can also help. (Be sure to consult your veterinarian before giving your dog any supplements.) Finally, a diet that allows your dog to maintain a healthy weight is very important for heart health.

Is There a Cure for CHF in Dogs?

Unfortunately, there is generally no cure for heart disease. However, with the right care, it is possible to manage, and most dogs do well with medications and treatment.

Is CHF Contagious for Humans or Other Pets?

CHF is not contagious. However, heart disease can be heredity, so veterinarians strongly advise against breeding dogs who have an underlying heart condition.

What Is the Cost for Treating CHF?

Diagnostic testing can be costly, and the medications used to treat CHF can be expensive, especially if they are given over a long period of time. Be sure to inquire about generic brands.

Recovery and Management of Congestive Heart Failure

It’s possible for a dog with CHF to live a happy life. But proper diet, monitored exercise, medications, and good overall care are necessary. Regular check-ups are important for monitoring a dog’s condition and assessing the effectiveness of treatments. Any change in health should be addressed immediately.

Preventing Congestive Heart Failure in Dogs

To prevent CHF, owners need to be aware of the signs and symptoms associated with heart problems and address them right away. Proper nutrition is important, but supplements can also play a role heart disease prevention.

Some preliminary studies have shown a link between grain-free diets and heart disease (specifically dilated cardiomyopathy). If your dog is eating a grain-free diet, speak with your veterinarian about whether your dog should change to a diet containing grain.

Is There a Vaccine for Congestive Heart Failure?

There is no vaccine that can prevent CHF.


Congestive Heart Failure in dogs is fairly common, affecting 75% of senior dogs. While there is no cure, medication and lifestyle changes can help manage the condition. As it’s not always easy to detect in its early stages, prevention is important; proper diet, exercise, and weight maintenance are key for canine cardiovascular health. Be aware of the signs and symptoms so you can seek help as soon as you suspect CHF could be an issue, and stay up to date on your annual vet visits.

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