Congestive Heart Failure in Dogs
Congestive heart failure is a weakness in some part of the heart pumping mechanism, or inadequate strength of your dog’s heart to meet its body’s need for oxygen. The heart consists of four chambers; the two upper atria and two lower ventricles. There are blood valves in between the chambers that open to allow one-way flow to the ventricles, and close to prevent backflow into the atria. The left side of the heart pumps blood out to the body, while the right side pumps blood to the lungs.
Congestive heart failure tends to be more prevalent in older and obese dogs. Very large dog breeds, as well as toy and teacup-sized breeds seem to be more prone to this condition.
Signs & Symptoms of Congestive Heart Failure in Dogs
Depending on which side of the heart is weakened or disabled, your dog may exhibit different signs early on:
- Shortness of breath
- Unproductive coughing due to build-up of fluid in the lungs - mostly found in left-sided heart failure
- Fainting or collapsing
- Loss of appetite
- Bloated belly due to build-up of fluid in the chest cavity - mostly found in right-sided heart failure (less common than left-sided failure)
As the problem progresses, distress, labored breathing, gray/blue gums, dilated pupils, and seizures may occur. This could be an emergency situation and you should contact your vet ASAP.
Causes of Congestive Heart Failure in Dogs
Heart problems and failure can be caused by old age, a number of diseases, heartworm disease, birth defects, or, most commonly, a build-up of fluid in or around the heart (congestive heart failure). Congestive heart failure is caused by an abnormality in the heart, resulting in a back up of fluid in the heart, lungs, or chest cavity. This could be caused by too much fluid or pressure in the heart, the heart’s contractions not being strong enough to empty the chambers, or the chambers not being able to hold an adequate amount of blood.
Diagnosis of Congestive Heart Failure in Dogs
Diagnosis begins with a complete history and a physical exam of the dog. Your veterinarian will most likely do the following:
- History and Physical Exam - Your veterinarian will likely listen to your dog’s heart with a stethoscope to observe any murmurs or gurgling sounds indicating a build-up of fluid. They may also take a blood pressure reading, which is typically a non-invasive process requiring no sedation. Your dog’s symptoms and breed history will be taken into account in their diagnosis.
- Radiographs (X-rays) - This may show clouded lungs or abdomen, indicating fluid accumulation. X-rays may also show an enlarged heart.
- Ultrasound - This can be used in many diagnostic processes to determine abnormalities in your dog’s body. Ultrasounds use sound waves that bounce back, producing an echo that measures the opacity of objects, and produces a picture on the ultrasound machine. When an ultrasound is performed to observe the structure of the heart, it is called an echocardiogram.
- Electrocardiogram - This test measures and records the electric impulses of your dog’s heart. This is usually done by clipping small contact electrodes to your dog’s limbs.
- ELISA testing - Your veterinarian may wish to test your dog for heartworm disease if your dog is not on a heartworm preventive. This will help them rule out heartworm disease as the cause of heart problems and coughing. ELISA stands for "enzyme-linked immunosorbent assay," and is a test used to determine if a dog has been exposed to a certain pathogen by seeing if its body has produced antibodies against the pathogen. It can be used to test for viruses, bacteria, microbes, or other material. This SNAP ELISA test requires just a few drops of whole blood from your dog and can be run in about 10 minutes. This test will show a positive if there is enough of the heartworm antigen in the bloodstream. Once it is positive, an additional blood test known as a direct test is done, again taking a sample of whole blood to examine under the microscope so the young heartworms can be seen.
Treatment for Congestive Heart Failure in Dogs
There is no cure for congestive heart failure, but measures can be taken to extend and increase the quality of your dog’s life.
- Your veterinarian will likely prescribe drugs that will alleviate the fluid pressure in the heart and lungs, as well as regulate the heart beat.
- A drug called Vetmedin is often prescribed to open up your dog’s blood vessels and reduce the amount of work their heart has to do to pump blood.
- A diuretic drug such as Furosemide may be prescribed to flush the fluid out of your dog’s cavities.
- A thoracocentesis may be performed to manually drain the fluid from your dog’s lungs with a needle. This may require sedation and/or an ultrasound to help your vet guide the needle.
- There are multiple natural supplement options for dogs with congestive heart failure; those that include potassium, taurine, selenium, chromium, and L-carnitine, among others.
Prevention of Congestive Heart Failure in Dogs
Keeping your dog at a healthy weight for their size can greatly assist the heart in pumping blood. The more overweight your dog, the harder its heart has to work, and the more severe the heart issues. Talk to your vet about ways you can help your dog lose weight through exercise (consult your veterinarian first before engaging your pet in any strenuous exercise) and a reduced-calorie and low-salt/high-protein diet. An adjustment in your dog’s lifestyle may be the answer.
Early diagnosis of congestive heart failure can prevent further fluid accumulation and heart deterioration, and may elongate your dog’s life.