Congestive Heart Failure in Dogs
Congestive heart failure (CHF) is most often a result of the left side of the heart being unable to move blood out and through to the rest of the body, leading to edema formation. Edema is fluid in tissues or body cavities that should not be there. In left-sided heart failure, this edema most often accumulates in the lung tissue or chest cavity making breathing difficult. Continue reading to learn about common causes of heart failure, symptoms, testing, and treatment options for dogs.
This article was written by a FirstVet vet
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How do dogs develop congestive heart failure?
Left-sided heart failure is the most common cause of congestive heart failure in dogs. This is typically due to mitral valve disease, dilated cardiomyopathy, hypertrophic cardiomyopathy, and congenital heart defects like a patent ductus arteriosus. These heart diseases cause the heart to be unable to pump blood efficiently to the rest of the body. They may also raise the blood pressure in the veins causing fluid to leak out into other tissues or body cavities.
What symptoms might I notice if my dog is in heart failure?
Dogs with left-sided heart failure often have:
- A heart murmur, which is often present before developing heart failure. A murmur does not mean your dog will develop heart failure!
- Rapid breathing
- Labored breathing (increased effort, often abdominal push when breathing)
- Exercise intolerance
- Rapid heart rate
- Abnormal heartbeats/arrhythmia
- Blue coloration to gums or tongue (cyanosis)
- Tissue swelling around the muzzle in severe cases
What tests might Be needed to diagnose congestive heart failure?
A good physical exam and auscultation (listening) to the heart and lungs are the first step. Before additional and sometimes stressful tests, your vet may recommend a sedative to relax your dog and let them calm down. Supplemental oxygen may be given if your dog is showing signs of stress or respiratory distress.
Once your pup is relaxed and stable, chest radiographs (x-rays) are often the next step. This allows your vet to look at the size and shape of the heart and vessels in the lungs, along with looking for abnormal fluid in the lungs and chest. If there is a lot of fluid present, it can obscure the heart itself, so radiographs may need to be repeated once the fluid has been removed and to assess response to treatment.
An echocardiogram, or ultrasound of the heart, is another good test. This allows your vet or cardiologist to look inside the heart at the valves and vessels and measure how much blood the heart is pumping compared to normal.
If your dog has an abnormal heartbeat, an electrocardiogram (ECG) may be recommended to determine the type of arrhythmia so appropriate medications can be given to control that.
Finally, there is a blood test called NT-proBNP Assay. This test detects a certain peptide that is released when the heart wall muscles stretch too much. This is a good screening test for breeds of dogs that more commonly develop congestive heart failure such as King Charles Cavalier Spaniels, Boxers, and Doberman Pinschers.
What treatments are available for dogs with congestive heart failure?
During an acute congestive heart failure crisis, your vet will give your dog injections of various medications such as furosemide to help remove excess fluid from the body. They may also apply nitroglycerin ointment to help dilate the veins. Pimobendan is a pill that helps the heart contract better. Occasionally, dopamine or dobutamine are needed in severe cases. Sedatives or stress reducers are also often given to help your pup relax and breathe easier as the other medications start to take effect.
Long-term treatments to continue at home once your dog has been stabilized include:
- Furosemide or spironolactone pills given multiple times per day to reduce fluid overload
- Pimobendan to help the heart contract more efficiently
- Enalapril or benazepril to reduce blood pressure
- Appropriate medications to treat any arrhythmia that may be present
- Low sodium diet!
Monitoring After Treatment
Once your dog is started on medications to help reduce the frequency of CHF episodes, they’ll need regular blood work and recheck exams to assess how their organs are tolerating the drugs and reduced heart function. Close monitoring of your dog’s electrolyte levels is also necessary, as furosemide can cause severe losses of potassium.
Monitoring your dog’s Resting Respiratory Rate is a critical part of good home care. When resting (laying down napping or relaxed), the heart rate should be below 30 breaths per minute. If your dog consistently has a resting respiratory rate over 40-50 breaths per minute, they need to go to the vet immediately for an exam, chest radiographs, and in-hospital treatments to get them out of heart failure.
Unfortunately, there is no cure for heart failure. The medications are to help reduce fluid overload and give your dog more quality time in between episodes of heart failure. As the heart continues to deteriorate, the medications will be less effective and the heart failure episodes will become more frequent. If you have any concerns about your dog’s quality of life, please discuss this with your vet or schedule a consult with us at FirstVet.
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