A diagnosis of congestive heart failure for your dog can be a worrying time. You will probably have a lot of questions and all of the new information can sometimes be overwhelming. Sadly, congestive heart failure in dogs is a relatively common disease but with an early diagnosis and the right treatment, lots of dogs can live happily for many months and often years. In this article, we’ll take a closer look at the symptoms of congestive heart failure in dogs. The sooner your dog is diagnosed, the sooner she can begin treatment and this will give her the best chance of a longer life.
What is congestive heart failure in dogs?
Congestive heart failure (CHF) is a condition that results in the build-up (congestion) of fluid within the body due to the heart’s reduced ability to pump blood effectively. Fluid can back up into the lungs, abdomen, liver, and limbs. This fluid congestion can result in the constriction of the heart and lungs, which further reduces the heart’s pumping ability and thus reduces the delivery of oxygen to vital tissues. CHF can progress slowly and can sometimes happen over months to years.
In dogs, congestive heart failure is usually described as left-sided or right-sided:
Left-sided congestive heart failure
This is the most common type of heart failure in dogs. When the heart contracts, some blood from the left ventricle leaks back through the mitral valve into the left atrium, instead of being pumped around the rest of the body.
This results in fluid backing up or congesting the lung tissue and this is called pulmonary edema. As you might imagine, this leads to difficulty breathing or panting and can also cause coughing, amongst other problems.
Right-sided congestive heart failure
This occurs when during a heart contraction, some blood from the right ventricle leaks back through the tricuspid valve into the right atrium, instead of being pumped to the lungs to be oxygenated.
As a result, the systemic circulation becomes congested with blood causing the abdomen to fill with fluid. This is called ascites and can prevent the abdominal organs from functioning properly. The congestion of the systemic circulation can also cause fluid to leak out from the veins into the surrounding tissues and can result in swelling of the legs. This is called peripheral edema.
What are the symptoms of congestive heart failure in dogs?
Here are some common symptoms that could indicate your dog is suffering from CHF:
- Becoming tired more quickly than usual when on walks or when playing – this is due to poor oxygen flow through the body resulting in less energy.
- Coughing – this is mainly due to the fluid congestion within the lungs.
- Panting at abnormal times, for example, when they aren’t hot or haven’t been exercising – is the body’s attempt to increase its oxygen levels.
- An increased breathing rate when they are resting or sleeping – this happens because fluid accumulation within the lungs restricts the movement of the lungs, resulting in more frequent breaths in an attempt to maintain oxygen levels.
- Reluctance to exercise – exercise becomes more difficult for your dog because of reduced oxygen flow through the body. Breathing is more difficult due to fluid accumulation within the lungs.
- General fatigue – this is because less oxygen flow through the body means less energy.
- Loss of appetite – often as a result of feeling unwell.
- Unexplained weight loss – often due to an increased need for energy and a reduced appetite.
- Blue-tinged gums – this is referred to as cyanosis and happens due to a lack of circulating oxygen.
- Coughing up foam or blood – this can happen as a result of fluid congesting in the lungs.
- Distended abdomen – this is seen in right-sided CHF when fluid congests the abdomen.
- Fainting or collapsing – this can happen when blood flow to the brain is reduced.
The signs of congestive heart failure can progress slowly over time and might not be obvious at the outset. This is why it’s important to take your dog to the veterinarian to get her checked over if you suspect she might be showing any of these signs.
What causes congestive heart failure in dogs?
Most causes of CHF in dogs are because of congenital defects, or in other words, a genetic problem that they have been born with.
The most common of these is myxomatous mitral valve disease (MMVD). The mitral valve sometimes called the bicuspid valve, or left atrioventricular valve, is the valve between the left atrium and the left ventricle of the heart. MMVD results in blood leaking back through the mitral valve from the left ventricle to the left atrium, causing fluid to back up into the lungs. Some small dog breeds such as the Cavalier King Charles Spaniel, Toy Poodle, and Pomeranians, have a greater genetic predisposition towards developing MMVD than other breeds.
Another hereditary cause of CHF is dilated cardiomyopathy (DCM). This tends to affect large or giant dog breeds such as Dobermans, Great Danes, and St. Bernards. In this condition, the heart muscles become weak and fail to contract properly, resulting in enlarged (dilated) chambers of the heart.
Below are some other causes of congestive heart failure in dogs including:
- Congenital heart defects such as aortic stenosis, pulmonic stenosis, and patent ductus arteriosus.
- Congenital hole in the heart (ventricular septal defect).
- Heart valve disease which can sometimes be caused by infection and is known as endocarditis.
- Fluid accumulation in the membrane that surrounds the heart (pericardial effusion).
- High blood pressure.
- Heartworm infection.
- Tumors in or around the heart.
How is congestive heart failure in dogs diagnosed?
Your veterinarian will want to know about any symptoms in your dog that you may have noticed. They will perform a full clinical exam of your dog, including listening to her heart and lungs with a stethoscope (auscultation) and checking her blood pressure as well.
Many dogs with CHF will have a heart murmur that your veterinarian can hear with their stethoscope. Heart murmurs are caused by turbulent blood flow within the heart as it leaks through the valves. They can be graded according to how loud they are.
Your veterinarian may suggest some blood tests to check your dog’s general health. It is also possible to run blood tests to check your dog’s cardiac biomarkers. These can help your veterinarian to assess your dog’s heart health.
Chest x-rays can be used to measure the size of your dog’s heart and detect fluid within or around the lungs. X-rays of your dog’s abdomen might be performed to check for ascites (fluid congestion within the abdomen).
Sometimes your dog might need to be referred to a veterinary cardiologist for more specialist testing. This might involve an ultrasound of your dog’s heart (echocardiogram) which can assess the size and thickness of the heart’s chambers and its vessels as well as evaluate the flow of blood through the heart. Measurements can also be taken to assess the heart’s pumping ability.
This measures the electrical activity of the heart and can detect any abnormal heart rhythms or arrhythmias.
What are the stages of congestive heart failure?
CHF can be categorized according to its severity, similar to the way it is in humans.
Stage A – This is the lowest stage and is for dog breeds that have an increased risk of developing CHF, such as Cavalier King Charles Spaniels or Dobermans, but that currently have no structural changes to their heart and are not showing any symptoms of CHF.
Stage B – Dogs that have a heart murmur that can be heard by the veterinarian with a stethoscope, but that do not have any other signs of CHF.
Stage B2 – Dogs that have a structural change to their heart seen on x-ray or echocardiogram, but that have no symptoms of CHF.
Stage C – Dogs in this stage have symptoms of CHF but their symptoms can be well managed with medications.
Stage D – This is end-stage CHF whereby dogs no longer respond to medications and have severe symptoms.
What are treatment options for dogs with congestive heart failure?
There is no cure for CHF but it can be successfully managed for several months to years with medications. Your dog is likely to require a combination of different medications to help manage her CHF. These will need to be taken every day for the rest of her life and might include:
- A diuretic to help remove excess fluid from building up in the lungs.
- An ACE-inhibitor to lower blood pressure.
- A positive inotrope to help increase the heart’s ability to contract.
The number and combination of medications that your dog requires will depend on the cause and severity of her CHF. Dose adjustments may need to be made depending on your dog’s response to treatment and as her CHF progresses.
Do I need to alter my dog’s lifestyle?
Once your dog has been diagnosed with CHF, he will need regular vet check-ups and sometimes blood tests to monitor her kidney function which can be affected by heart medications. Your veterinarian might recommend a prescription diet to help support your dog’s heart health. Most dogs with CHF can exercise normally once their symptoms are controlled but they should be allowed to rest when they need to.
Your veterinarian will teach you to count your dog’s sleeping respiratory rate (SRR). This is one of the best ways for you to monitor at home whether or not your dog’s symptoms are controlled. An increase in SRR usually indicates that your dog’s heart failure is getting worse.
What is the prognosis for congestive heart failure in dogs?
Although there is no cure for congestive heart failure in dogs, many can live happily for months or even years with the correct treatment. Treatment is aimed at reducing the severity of your dog’s symptoms and improving her quality of life. The sooner your dog is diagnosed, the better her chances of long-term survival are, so do not delay in taking her to the veterinarian if you suspect she is showing any of the above signs of congestive heart failure. If you do not already have a veterinarian then check out www.bettervet.com to find one near you.
How long can a dog live after developing congestive heart failure?
This depends on how far your dog’s heart disease has progressed by the time she is diagnosed. An early diagnosis can lead to many months and often years with successful treatment.
Is congestive heart failure in dogs painful?
Although heart failure isn’t usually painful, the symptoms it causes can be very uncomfortable and often distressing for a dog. If fluid accumulates in the lungs, it can feel as though they are drowning.
How do you know if your dog’s congestive heart failure is worsening?
Symptoms such as exercise tolerance and coughing may get worse. You may also notice extra symptoms that weren’t there previously, such as a swollen belly, or collapsing episodes. An easy way for you to pick up early changes is to monitor your dog’s sleeping respiratory rate. Your veterinarian will show you how to do this safely at home.