The first symptoms of congestive heart failure in dogs are subtle. Your dog may seem less active and not eating well. He may be coughing a bit. Don’t dismiss these signs as the dog is just getting old. These changes could indicate congestive heart failure, and the earlier it’s diagnosed the better the prognosis.
Other early signs of heart failure include:
- Increased respiratory rate
- Struggle to breathe, especially after any exercise
- Moist cough, even at rest
More advanced symptoms of heart failure are:
- Abdominal swelling/fluid retention (ascites)
- Edema in their lower legs
- Weight loss
- Pale or bluish gums
Causes of Heart Failure in Dogs
The two biggest causes of congestive heart failure in dogs are mitral valve disease and cardiomyopathy.
Mitral valve disease is a degenerative condition that affects the valves that separate the chambers of the heart. When valves develop problems, blood can leak back into the chamber it was just pushed out of. This means less oxygenated blood gets to the tissues, forcing the heart to work harder to compensate.
Cardiomyopathy is a disease that affects the heart muscle. Depending on the exact scenario, the heart may stretch (dilated cardiomyopathy) or expand (hypertrophic cardiomyopathy). Both conditions make the heart less efficient, so, again, causing the heart to work harder. Tissues may be deprived of oxygen.
Congestive heart failure also may be due to genetic predispositions (such as mitral valve disease in Cavalier King Charles Spaniels), infections such as viral or bacterial myocarditis, or parasitic infections like heartworm. Certain diets may predispose some dogs to congestive heart failure as well.
Other causes of heart failure in dogs include hypertension, tumors, abnormal heartbeats, mitral regurgitation, and more.
Diagnosis of Heart Failure in Dogs
Whether found during a wellness exam or because you brought your dog in for a problem, your veterinarian may pick up a heart murmur (abnormal heartbeat) when listening to the dog’s heart. The vet may recommend chest X-rays, which may show enlargement in the heart. You may be referred to a veterinary cardiologist.
Diagnosing congestive heart failure is a combination of physical exam findings, radiographs or echocardiography (ultrasound/“sono”), and bloodwork, including a specific heart metabolite called NT Pro-BNP (see sidebar).
NT-Pro BNP or N-terminal fragment pro-B type natriuretic peptide is a cardiac biomarker detected in bloodwork. This biomarker has been used to diagnose heart disease to differentiate respiratory versus cardiac disease and to track progression and treatment of heart failure. It is a hormone produced by cardiac muscle cells when they are overstretched.
Stages of Congestive Heart Failure in Dogs
Veterinary cardiologists stage their patients to help track progression of the disease. Congestive heart failure cannot be cured in dogs, but their disease can often be controlled, providing them with good quality of life for months to years.
Five basic stages are generally recognized:
A: The dog presumed to be at risk. This could be a dog with a known genetic predisposition. At a minimum, these dogs should have annual physical examinations.
B1: The dog appears healthy, but a murmur has been detected, so they need periodic re-evaluations.
B2: These dogs also appear healthy, but in addition to a murmur, some changes in heart structure are evident on radiographs or echocardiography.
C: At this stage, your dog is showing clinical signs of congestive heart failure and is starting medical therapy (see treatment, below).
D: Dogs at stage D have congestive heart failure that medical therapies aren’t controlling. These dogs usually require hospitalization, often with supplemental oxygen, while your veterinarian works to get the symptoms under control.
Treating Congestive Heart Failure
Treatment for congestive heart failure often involves a bit of trial and error to come up with the exact treatment that works for your dog.
The first step is usually prescribing a diuretic such as furosemide (Lasix). Diuretics decrease blood volume and reduce venous pressure. These actions make it easier for your dog’s heart to beat and get oxygenated blood out to tissues in the body.
Furosemide is a relatively inexpensive oral medication, though it can also be given intravenously to a dog in crisis, along with the use of supplemental oxygen.
Other medications will vary with the underlying cause of the congestive heart failure:
- Pimobendan is often given to help the heart work more efficiently.
- ACE inhibitors dilate blood vessels so less resistance for the heart to pump against.
- Antiarrhythmic drugs help control your dog’s heart disease.
Dietary Changes for Dogs with Heart Problems
Dietary changes may be recommended as well. A diet low in sodium can help some dogs, and all canine cardiac patients can benefit from supplementing omega-3 fatty acids, such as fish oil.
For some dogs, adding taurine to the diet may help. The associations of certain diets with dilated cardiomyopathy in dogs has not been clarified at this time, but your veterinarian may recommend changing diets if this is your dog’s diagnosis.
The most important thing about diets for dogs with heart disease is that your dog must like the food. Cardiac cachexia is a real thing. It’s when dogs lose weight and muscle mass related to heart disease, often from a loss of appetite. So, talk with your veterinarian as you may need to “fudge a bit” on feeding a strict cardiac diet, using toppers and other foods to help keep your dog eating.
Home Care for Heart Failure in Dogs
If your dog is diagnosed with congestive heart failure, try to minimize stress at home. This is not the time to add a puppy or have a huge family gathering. Try to keep to your basic routines as much as possible.
Continue your daily exercise but adjust as needed. You might need to shorten the length of walks or avoid places with steep hills. Adjust your pace to fit your dog. Do lots of snifari walks (“sniffer walks”) where your dog sets the pace and direction.
Learn your dog’s normal respiratory rate and how to monitor the rate. Normal ranges for resting rates in dogs can range from 10 to 30 breaths per minute or so. Small dogs have a higher rate than giant breeds. Most people count the breaths on their sleeping dog for 30 seconds, then multiply by two. If your dog’s resting rate increases or he is laboring to breathe, contact your veterinary clinic.
Congestive heart failure is no fun, but with care and a bit of luck, your dog can enjoy many more months or even years with you.
