Signs & symptoms of end stage canine congestive heart failure

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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 and most treatment is palliative – geared to make the remainder of your dog’s life more comfortable.

Loving dog owners learn to recognise 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.

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 happens, your dog will acquire a chronic, hacking, unproductive cough and your veterinarian will probably be able to hear a crackling sound deep in his lungs.


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


As more fluid builds up in your dog’s lungs, she will experience episodes of laboured breathing, called dypsnea. She may show signs of open-mouthed breathing with some vocalisation. Laying 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 grey as the lungs begin to fill with fluid. Called cyanosis, this condition means that the heart is not pumping the correct amount of oxygen-carrying blood from the lungs out into the rest of his body tissues. With not enough red 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 not eat as much as before. Her digestive organs will start to fail due to blood and oxygen deprivation, and her body cannot utilise the nutrients from the food she eats. Your dog may also suffer from bouts of diarrhoea and vomiting, indications that her digestive system is shutting down.


The end stages of heart failure typically show with fatigue in dogs. Your pet may be unwilling or unable to move around and some show heavy, laboured breathing after exertion. He may become less active and tire easily. Your dog may suddenly collapse or faint (called syncope). The lack of oxygen to your pet’s muscles will not allow for normal movement, and, eventually he may become unable to rise or stand on his own.