Signs & Symptoms of End-Stage Canine Congestive Heart Failure

When your dog is diagnosed with congestive heart failure, you must prepare yourself for the inevitable. Veterinarians know that heart failure is progressive and incurable. Most treatment is palliative – geared to make the remainder of your dog's life more comfortable. Loving dog owners learn to recognize the end stages of their pet's disease so that, when the time comes, they have the knowledge to make a difficult decision easier for both themselves and their beloved pet.

Golden retriever dog lying on sofa, close-up
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Pleural Effusion

Dogs in end-stage heart failure develop pleural effusion – fluid in their lungs. Because the heart is not functioning to capacity, hypertension (high blood pressure) forces body fluids to seep into spaces in the lungs and they, too, begin to fail. When this seepage occurs, your dog will acquire a chronic, hacking, unproductive cough. Your veterinarian will probably be able to hear a crackling sound deep in her lungs.


Your ailing dog may also start retaining fluid in her abdomen and limbs. Called ascites, this fluid retention shows as a swollen, pear-shaped belly and puffy legs and feet. Limited heart function causes the blood vessels in your pet's body tissues to be unable to redirect fluid into the kidneys and out of her body.


As more fluid builds up in your dog's lungs, she will experience episodes of labored breathing, called dyspnea. She may show signs of open-mouthed breathing with some vocalization. Lying down can become painful and distressing to your dog, so she may sit in a posture with her chest raised and head up to facilitate easier airflow.


Your pet's gums and mucus membranes will become blue or gray as her lungs begin to fill with fluid. Called cyanosis, this condition means indicates that her heart is not pumping the correct amount of oxygen-carrying blood from the lungs out into the rest of her body tissues. With insufficient oxygenated blood in the capillaries, your dog's tissues appear pale and mottled.

Weight Loss and Digestion

As heart failure progresses, you may notice substantive weight loss in your dog. She will begin to lose her appetite and will not eat as much as before. Her digestive organs will start to fail due to blood and oxygen deprivation. Her body will be unable to utilize the nutrients from the food she eats. Your dog may also suffer from bouts of diarrhea and vomiting, indications that her digestive system is shutting down.


The end stages of heart failure typically show as fatigue in dogs. Your pet may be unwilling or unable to move around and some show heavy, labored breathing after exertion. She may become less active and tire easily. Your dog may suddenly collapse or faint, a condition called syncope. The lack of oxygen to your pet's muscles will not allow for normal movement, and, eventually, she may become unable to rise or stand on her own.